Transcript for:
Magnetism and Moving Charges

Welcome all of you to the place of Science and Fun But teachers teach you with both your heart and mind If you teach, I have brought a lot for you very excellent very cute Crisp Moving Charges and Magnetism one shot of ka kuch batayein one shot [ __ ] too soon before starting In the above you must have seen that having a one shot Gonna be with ex riment a more question The answers are available separately for that live Sessions are taken whenever we take one shot When you record it, it is very crisp keep it full of concepts After that live sessions or recorded We are very important in form If you ask questions then first, second and One shots of the third chapter are out Experiment 4th chapter is coming and if If you want to see the question answers then see the recorded There are one or two lectures in the form also but go live in very nice very lovely forest The shots have been cast for you and then they go live were you guys said that moving charges Cast one shot of magnetism quickly then this I have got it for you next week One Shot of Moving Charges and Magnetism Now this chapter is so cute, it is obvious that It is a matter of electrodynamics, i.e. here Tell me the name of the person who moves the pay charge because the first two chapters are our of electrostatics Now whenever a We would get electric current flowing through the conductor We have read about the current in the previous chapter then whenever the current through a conductor When it runs we see three effects can meet or meet there is one We have studied the heating effect in the previous chapter. there's a chemical effect now which It is obvious that there is a chemical effect it is a part of chemistry and an electro The chemistry that I hope is still mostly there Children must have read Electro The whole chapter of chemistry is on it This is where we experience chemical effects from electricity produce any chemical reaction but this whole chapter is This is completely based on the magnetic effect. that if I go from inside any conductor When I run the current it flows around me in your area in your region Magnetic field produces magnetic attraction produces a magnetic field then this This chapter is going to have two parts First of all the basic thing is what is a magnet A magnet is a small iron ball Cobalt attracts nickel pieces or if there is any magnetic field around it If he is able to create a field then you will understand that It's a magnet, it's a very basic LKG thing But in this chapter we will discuss two parts you are going to read this you can say this This part of this chapter is written first There is a forest where we can see the conductor from inside the current will be run and around it Magnetic field will come out from its design Its shape, its direction, its magnitude, all this We will calculate like we did in 10th class I had read that the current from inside the conductor What shape will the magnetic field take when it is run It is just necessary for us to know him in this chapter have to calculate and this will be part one and In part two of this chapter, we have to study that if from the inside of a conductor already Current is flowing and if it is kept at a And how does it behave in a magnetic field? These two things can happen to you right now you are not able to understand because give this It is a part of the chapter, you can say This is part one and this is part two of our let's start this chapter This is Oster's experiment, you can also call it Everyone must have heard of Hans Christian Auster The full name was and accidentally he said something what did you discover come on what did you discover If you understand it then obviously this is a very He was a great scientist, he was a great scientist And it will be working on one of its circuits. For now, we are assuming that This is a simple obvious thing, son I am saying this again on such a simple circuit So everyone must not be using this much intelligence this bulb must be a great man It would not be burning after putting in the battery then For now let's take a simple one We imagine a circuit here in which here we have a switch here We have a battery and we have a bulb okay right now there's one nearby A compass was lying there, that is, a magnetic compass. There is a needle, it tells north and south There is a magnet now let us suppose that it is north If South is here then obviously Needle is also here The needle was here and it was here now it is very cute The thing was that when While he was working on this circuit, While working on the circuit, he was near The compass was lying there, the circuit was still closed As soon as he passed current through it got it done As soon as they turned this switch on basically did it or should I say closed it, then here what The bulb was lit and it started to glow It seemed obvious that the bulb started glowing started to glow and whatever was lying nearby There was a compass lying nearby, it was my It started to deflect from its place, where will it go We will read this too, but from our place It got deflected and started moving, now they Now I wondered what happened to a magnet needle Only magnets can deflect big things You must be surprised, obviously it happened If yes, then he did it multiple times it will happen and after that they did this phenomenon gave that whenever a conductor from inside When current flows, it creates a creates a magnetic field and that magnetic It is because of the field that this compass exists. If it got deflected then it was in the exam I won't be able to write but if you want you can give it to me can you write the lines that hans kirsten Ousted accident Tally discovered that when ever current carrying Conductor when ever carrying current The conductor is present in a particular area it will produce some magnetic field around it isn't it This was discovered accidentally Now you can tell from experiment whether this Actually it happens, yes it happens let's take a second and see what If I pass current through a conductor camera So will the magnetic needle be deflected? First let's see this and then move ahead we have a compass right and this we have a magnet right now look i have I have brought it anyway but we have this one There is a magnet and obviously it is a magnet By bringing this compass near it, getting deflected because inside the compass I have my own magnet now This magnet will have to be kept very far away now I'll tell you what I'll do until this I want the compass to come back to its place there is a wire you can see I will once this Let me zoom out, here I have a wire and what am I doing along the wire near the wire I will do it I have a sale here okay no what should i do now i will make a new one of this wire Put a part here and put a part here We have to do it quickly because this wire is hot too it will happen because I turn the positive into negative but if I can bring this near it I will keep it, you just wait and see what happens to it Let me wait a little while, then if I If I pass current through it then you will see what will happen i do this from a distance so that you can also see If you look at this, this wire has moved, right? Look, he has covered his entire North and South I have changed it but if I put it here if I remove it from there then it will return to its direction I would like to align myself very much It is sensitive, it takes some time Let's wait for it to stop, then I'll tell you I'll do it again ok is you can see because and its There is a reason to be sensitive because The Earth's magnetic field is that strong If not, it would have very weak magnetic You have to move on the field too, that's why It is important to be very sensitive to this okay now let's go back to almost It is coming to its place, now we are back to the same place let's work okay look aye this move from back Now if I remove it, it will come back If it comes to its place then it's Aud ji's This was basically the experiment, okay brother So it is said that for a current carrying conductor A magnetic field is generated around That means Hans was the one who found this thing kristen ousted but now it's very important that if we read the formula then there is a law here The most important part of this chapter is coming The topic is Bio-Savart Law Actually Biot-Savart Law tells you the magnetic How much field will be generated as you think Kalm's Law came in the first chapter who told me how much the floor would cost Such current carrying between two charges How much magnetic field will the conductor produce This will tell us a lot about But Sward Law Important now let us suppose we have here Pe is a current carrying conductor and In this, we assume an amount of current it's been up there okay so here at this point Let's assume some point p now this The point is this is a certain at a distance and here there is some magnetic It is obvious that the field would be creating This is a wire and current is flowing through it Because of Austetji's experiments we Now they know what they are creating around them there must have been a magnetic field okay now its The whole wire produces a magnetic field if you are doing so here I am one of them Taking a small DA element hmm what is this DA it is a kind of length element, this means that this entire conductor it's a small part okay right and this is a The vector dA is what we call the length element length element and this is basically a Vector is quantity and its direction Where is in the direction of current correct isn't it, it's a vector quantity Now the direction will be wherever the current is If I need a small piece of magnetic If you want to calculate the field then this piece which is basically this piece from this point it is at a distance from this point now that's it if r is a position then that too will be a vector R vector is done okay now because the deal is also a vector and r is also a vector then An angle is formed between these two and This is Theta and now everyone will need Bio What does Bio Sav say according to Sevat Law? Law to according to to biot sevt Law Magnetic Field Magnetic Feed Produced Magnetic Field Produced Bye Small Length Elementor deal at point near it's at point near it now listen carefully to it Different parts of this Bio Savat Law but the Bat Law says that the one who A small magnetic field is produced of a small element of the whole conductor For That is the first thing directly proportional this is a very current obvious thing my friend look at this Magnetic symbol of good magnetic field it is b capital b then small magnetic The symbol of the field it is generating What will happen I think common sense is the law and it has its place It is there but it is also common sense because current The magnetic field is generated because of Now the more current flows the magnetic The greater the field, the more the second point says that is directly proportional will be directly proportional to what This will also be directly proportional to this that how much element you took then directly proportional to length element if you The length element would have been larger than the length element If you had taken a bigger piece, it would have been more produces a magnetic field and the length If the piece of the element was taken smaller, then it would If it produces less magnetic field then This will create a magnetic field Whoever will get DA directly proportional If it also happens then it is directly proportional to The current became directly proportional to Length Element is Done and directly proportional to sign theta and this together directly proportional to sa theta is also now this sa What is theta brother theta angle is between is the angle then theta is the angle length element theta angle is the length element and position between the vectors then according to that which There is a magnetic field of theta This is directly proportional but Sav ji said He said you can use common sense like this again that if this point is here then theta will decrease if theta is less then they observed that the magnetic field would be less As the point approaches theta increases If theta increases then the magnetic field If it is increasing and if the maximum is at 90 After that it is decreasing again like this now Who grows from ro to 90 and after 90 If it is less then the answer is sai to bhaiya like this After some thought he said to Lett that the magnetic field is directly Proportional to sa theta is obviously a thing Its derivation must be from somewhere Now we have to study this law, so what? He just said that Bhaiya Magnetic field small magnetic field directly Proportional to current will be directly Proportional to length element will end The most important thing is directly proportional to It would be theta but it did not stop here At the end he said that inversely Proportional Inversely Proportional to Square of Square Off Distance means inversely proportional Two squares of distance will obviously be The thing is distance means here how much you want to find the magnetic field at the point ho means directly from the first three elements It was directly, but the distance for the averaging of the square of k then here also If it follows Evers Square Law then You should remember Kalm's Law too. of inversely proportional distances It was square, now if we add all of these up Combining First second, third and fourth if we take all these Connect the components together first If we add second, third and fourth then what The magnetic field was directly Proportional to current i is length element It has come and sa theta has come, right brother? Directly proportional to current d and sa theta but inversely proportional to r s i So when we add all these up we get this Now from here, if I use the sign of proportional I should remove it and if I want to apply equal then I should If you have to apply a constant da sa theta bar s so I have this somewhere Nor a small magnetic field anywhere It is obvious that the formula will come here But now we will also talk about the k constant But somewhere we have this small For a length element which is magnetic Formula for the field being created will come which is adi a sa theta bar r s into a constant which is k now like that we get 1 over 4 instead of k in Kalm's law I had put it here just like that Remember, the value of this k is up to 4 p. will do there was 1 up 4 pa n here pe hai /4 pi there pe n tha permit off There is no free space here but my ability is the same thing as permeability of Free space was also medium dependent It is also medium dependent, everything is the same The values are very different where k was 1 / 4 pa A0 here is k / 4p there is k value if you remember 9 * 10 to power 9 It was a very large value but here the value of k The value is going to be 10 to the power of -7 of 10 Power-7 which is very small and this is how it is known It turns out that the magnetic field is Magnet force is the electric field That is, much more than electric floors. It is weak, well we will talk about it now but The value of k for free space is Power of 10 is -7 i.e. value of /4 pa The power of 10 is -7 now what will be the unit of k Let us see this also brother, the unit of length what is the meter here square so a will cancel out its unit what do we have with ampere and its what is the unit tesla so if its We have a Tesla unit and its We have a meter as a unit and its If it is ampere then what is its unit? If the ampere on the Tesla meter is full What is the value of 10 to the power of 7 amperes on the tesla meter and if so We have the final formula for the magnetic field ka will come in place of k if I write na / 4 pi e sa theta bar r s so children these Like Kalm's Law, the first two chapters are for us that life, honour and pride, everything was like this in this whole This is the formula of every chapter whatever Mostly those who are going to read further are from this only or indirectly a lot will come from this Important Formula Bio Sewart Law Ne He said that the small magnetic field which is What will be that which is made from small pieces, ID A sa theta bar r s into a constant / 4 If this is a length element, then I will write I give Direction is in direction of Current means the direction of the current It will be the same, you just have to keep in mind that this is a Don't forget that it is a vector quantity because the theta angle is dl3 is going to be very useful it's done it's done now we're gonna do one more thing again bud will abolish the Savard Law and its application will come and that is in vector form now Because magnetic field is an obvious thing The unit of magnetic field is Tesla It happens, we read this in 10th After whom was it named Nikola Tesla By the name, when you grow up you will know that Nikola What special thing did Tesla do for us? But there is still some time left for that, right? Son, we are still very young for that. Nikola Tesla G Greatest Of All Time I respect them very much, my If his wallpaper was on my phone If I go into history, I don't know now. whether it will be seen or not but I have seen a lot I have also read their stories several times according to me that he is one of the best scientist who we The world has given them to me but let's move on to something else some other time. will talk but a small magnetic field I didn't get any ID now how to vector it Write in the form what am I doing look carefully this step is big I am important in the RHS to multiply the RHS by a I am dividing it, let's see what happens with this I've made this Look above, multiply by r and also below what will I keep then r k will come now you all Do you know the rule of cross product? is dl2 dl3 is applied what is applied with two vectors it has happened that theta is applied now whenever two what if we take theta along with the vector I to him vector upon r k now because this If it is a cross product then it is obvious We have represented it in what form in vector form then Biod Sevitt's law can be written as We have represented it in vector form And here comes a huge revelation. I hope you all know whenever someone's If cross product is done then the answer is always comes perpendicular if the cross and Do not need to find the direction of the dot product If it comes then it is fixed, if it does not come then search now do it youtube4 under 10 minutes ashu sir mil jayega A video of a cross using two straws I have given all directions of the product here I am getting it revised now if you know I need to find a vector cross b vector if this is a vector and this is b vector, and I need to find a vector cross b vector so i have fingers from a to b right hand You have to rotate where your thumb comes direction is in short if it is a The vector a b is a small angle, so a Vector cross b Vector a Vector cross b Vector so my thumb is inside right Now if I assume b is the vector crossing a I have to find out b vector cross n If it would have happened, my thumb would have filled the cross We have taken the direction of the product on ninth 11th I learned to say yes and no in class yes and we also know that the dl2 will be the length of the element and magnetic The field will always be perpendicular. K also means this thing is about red color brother Write it down somewhere that the magnetic field is always The length will be perpendicular to the element and r That means this is l and this is r, now suppose this is l if this is r then you have to do l cross means dl1 dl1 then my thumb came in then these two k will always be perpendicular i.e. dl1 If it is, then it will be a perpendicular vector There will always be a perpendicularity between these two here We also get this education from this and this constant It is also available and obviously it is medium If you change it, this will change and so will this It is medium dependent It has become medium dependent, did you understand? Cross product is going to be very useful in the future I would say stop the video and do this If you don't understand then stop the video and click five check this video again after a minute So that you can understand it and move forward I will teach you this in every single one but still I would say look at it once, otherwise move on Let's move on okay brother let's go now we'll start getting to the point where things are The questions in our exams are actually made still we are like but save the law means Well, how much have I read till now but butt sevat The statement of the law, all that, come a little bit It is difficult but yes the question which we have to study now We are starting and will build from there These are the chapters from where numericals are developed now how will you do the numerical, I have told you Told that live sessions are taken You can go there and see the numericals If you need to know numericals yourself If you want to practice then I am going to give you one of the best I know the best book which will help you in all your There is only one solution to the problem and that is Shivdas's books Shivdas's if you are 12th Do you buy the question bank book whose I am putting a photo of that book here The best thing about it is that one topic Wise I just put a A video was posted that what mistakes children often make do you wait for the complete chapter to be completed After that they ask themselves questions We are practising but it is not like this earlier I have to do it first, let's say four chapters of a chapter The parts are large, as if we When people reach the 7th or 8th slide So that first part is Ampere Circuit Law Before this you must have understood the Ampere Circuit Law first completed all studies and then If you make a question then you will find it topic wise in Shivdas The first thing you will get are questions and that is P along with y cuz a one is mainly in it pi y cues and in physics you know NCERT is mostly negligible The child scores p y q his By practising additional questions which are difficult for you based or any number of MC cues Objective Subjective All questions are either PY cues or similar If there are questions then there is no tension about the level I am not writing any book which is less If the level is more then you will get the link Shivdas Books will be found in the description You can completely trust our book Accept it and if you are impressed by our one shot If you are studying or are in our paid batch Bhaiya, that would be like icing on the cake book because all of us are the whole I'm going to follow the same book for the whole year okay let's go to the magnetic field at the center of circular loop Now we can call a circular loop People come here first to imagine So here we have a circular loop Now it is obvious that if in a circular loop If current is flowing then here we will make a a current came from here it is going from here and now please don't go back from here Understand that there is a gap here, this whole circular It is a loop, it was just shown to create a gap Bhaiya, there was a current from here but this is a complete is a circular loop with a center here By doing O and its radius is we have small r Now we have to find the center of this circular loop I want to find out the magnetic field, remember 10th class If the current clock in this circular loop I am going wise so I need to use my fingers You have to wrap clockwise, if the thumb comes inside When this happens the magnetic field gets inverted and If the current is flowing anticlockwise then You have to wrap your finger in such a way that your thumb comes out If I go then my magnetic field will be o At the point it will be outwards i.e. There is a magnetic field, today we will How many magnetic fields are you going to learn If it happens then for this we have issued a circular Considerations let us take a circular loop of Radius small r having current come in clock wise direction lets go from now to now Suppose I have this little piece for this here's a small piece dl7 vert law according to to bad sevart's law which is a small magnetic field this d element will be creating its What will be the formula / 4p Now let's put the values in with bar s Which ones do we know? So 0 / 4p is 4p is i we have i dl9 if I dl8 90 if I took d here r here then angle is always 90 radius so it is obvious makes a 90° angle with the frame of the slide If it is theta then it will be 90 here, I hope Do you remember theta? dl9 will come up with r of sin90 What is the value of sin90 brother If it happens then / 4p /r s I will get the formula now if If formula / r s comes then after this I I can't solve this now what do I do I will do it, a small magnetic field has appeared So to find the total magnetic field I will do it The integration is then Integrating Both Sides on Both Sides I have to do integration so a small thing its magnetic field is if i If I do integration 0 / 4p i bar s all this isn't it is constant 0 4 p i s all this is is constant right but the It is not now db9 has 4p r s and this is what dlp.ac.in has this but it is insulated If there is a wire and you don't understand then do it like this We will make it, so don't worry about him So taking the whole circle into account, we have 2p r Answer will come pa to pi cancel r to r cancel and to cancel then 0 i / 2r We will get the magnetic field through this I have told you the directions to the center. Now we have further rules for all two directions You will read it but I have told you the direction If it goes clockwise then it will be inverted If you are going anticlockwise then you will be out at center well now this is when we have How many turns are there in a circular loop? One turn Yes, we haven't considered any turn yet, but If it has a number of turns That means one turn came, two three turns and doing this So if in this circular loop a number of there are turns for a turns so the magnetic field is we will have 0 n up in 2r so It is obvious that it should be multiplied by n will go because everybody's magnetic field center Pay add on will be for a circular loop The magnetic field at the center of We have derived the formula and what is the formula 0 n / 2r here Do you know what the ultimate ability is? The value is 4 pa * to the power of 10 -7 because /4p to the power of 10 is -7 i current and r is its radius plus now it is large Interesting and the best part of this chapter we are going to come to the derivation because right now we What work were people doing? We have just issued a circular worked on the center of the loop, now we have to do the same not at the center of the circular loop but on the axis I want to work, did you understand what axis means? if I tell you like this, here right now Imagine there's a circular loop here Here it is, this circular loop, imagine it okay So right now we have a magnetic field at our center Find the field. Now we can find its axial point. that is, from its center but towards the outside want to remove the magnetic field The diagram is the most important so this is my a circular loop this is my circular loop now we Looking at the circular loop from the side, right isn't it and again in this circular loop this in circular loop It is obvious that current is also flowing So it will create a magnetic field from here Current went and current came from here so now we From where are you looking at the circular loop, brother? If you are looking from the side, we have just seen a little magnetic field was removed some time ago at the center its at the center its O name It is drawn at the center, whose radius is Radius of our pass whose radius we had r now we have What do we have to do now to solve the magnetic field? Find the axial angle at its axial point means this was the center of the circular loop now For this we have to do this at the axial point here we have to extract the magnetic field which let us it's a distance away from it okay We do not write that distance in consideration Now what am I gonna do if I have to Assume the magnetic field at this point is If I want to take it out then how do I take it out at this point magnetic field so first of all again I Slice a little bit off the top of the circular loop And that little piece of me It is near to Lets dl5 current goes dl8 is going inwards so is dl2 right it is not there and this The distance from dl8 is this much maths comes if this is r this is a then this will become a √ r s + a of Pythagoras Now if you apply the maths according to your calculation, cross If you apply the product then this d is inside is on the side and this is the position we have that is r s + a s now the magnetic field What is the formula for magnetic field formula dl1 dl1 By doing this the magnetic field that I get You will find it in the direction below This will go dl1 I'm saying it again about the cross product If you are weak in direction then go now and watch the lecture son or else go ahead and Problem is going to come because in this chapter Many times, we use cross product now this is what the d is for The magnetic field is dl8 and is perpendicular You have to understand the 3D diagram in the plane If you have to make it in 2D plane then understand It will be here now and this one r is like this so again dl1 dl1 Its magnetic field will come up its magnetic field will come towards She will go in this direction now Like this every one of why did you do it for dl2 also because one thing I realized that one job was enough for two why did you do it, what do you want to explain Let's see again, we also have r s + a it will happen now because this is a small This element has a magnetic field and this This element has a small magnetic field Now let's lay down this angle That is the alpha diagram which is the most important Nobody will explain this to you in such detail. the angle is alpha now if this angle is alpha so we're gonna do this one look this is angle alpha so this one the angle is 90 yes this angle is also 90 yes I talked about it today that the magnetic field is always 90° from r so if this angle is 90 this one angle is 90 and this angle is common then if this If alpha is then this angle is also alpha It will go brother, basic maths is very important lovely maths and if this is alpha then this the component of this will be d b cos alpha And this is what we have dbssoin0811 If you look carefully at this diagram all of the dl8 will come here and they will be added but will cancel out A for each component Suppose there is a circular loop, then these two opposite dl2 d a will happen with them too here and there here here here here here here here here here here here the point is her opposite will cancel out the components containing Tell the sign people who are taking so long to advertise will apply derivation on son and one shot It's okay inside, be careful, that's why I'm saying yes son dear please like and Write in the comment section how you liked the one shot Because your likes and comments are our There is motivation for this, come on, what shall we do now We are going to do it, we will write down the consideration first If you want to write then let us take a circular loop of radius small carrying current come we can observe that sine component of magnetic field will add up where as components will cancel out hens hens now if i get total If you want to remove the magnetic field then how do you do that Let me take out the first thing which is the total Now that will be the magnetic field db2 what is my standard sign theta by 4 pa aa squa this is the formula okay it The aa with distance is the aa with y, not me If you are getting confused I will tell you Let me write this as the square of aa now. I have written in place of DB along with sign Alpha will definitely come, now you can use this formula Do you understand Bio Save Law, now the main thing is coming Bha, what are the constants in this? is a constant i is a constant come sa theta let's talk about d here was r s a s that is This one r is for us, this one here is the angle how much 90 take any d take any r Take any d, take any r, what is the angle will remain 90 so theta becomes 90 and gets removed ok or i will take it out with 90 comes So now who else has come out tell me 4 pa But this which is not r is d and the distance between these points, which is is r s a s a hole square r s + a s under root its hole square okay so this it came out it came out it came out it came out it came out it came out Now who has gone inside, survives inside Who d and together we survive sa alpha now what is the alpha constant let's talk about this one first If we finish the sign then it becomes 90 and then this has come na aa upon me 4 Will the square root cancel out? yes then r will become s p a s okay now Sa Alpha, this is the angle that is being formed right now It is a constant, so it also has to do with alpha Let's take it out, why didn't you take it earlier So that there is no confusion as to what is left inside now d survived now what is d what is small piece I integrate all d A so Again what will I get 2 come here But I already have a magnetic field Come on who all have come out already come 4 pa 4 pa r s + a s now listen attentively what is alpha san perpendicular upon base sa alpha if this angle is alpha then who is perpendicular who is perpendicular is r is upon me base perpendicular sorry sorry sorry perpendicular upon me Hypotenuse sorry perpendicular upon hypotenuse Perpendicular upon base then t theta So perpendicular upon hypotenuse r s p a s In whose place have we placed it, brother, we have placed it in place of sa alpha who is in place of sa alpha place now d ada d ada d a d a d ada tax If I give it, what will I get? 2 paise son, many Kids must be wondering why it's so slow Son, this derivation is like this, children Don't think that sir teaches slowly Check out the previous one shots but in this chapter Derivation itself is so dangerous if I hurry If you go, you will get confused, son, now look here don't come r so there is 4 par spa sc in me to the power of 1 and here it is half so r is power of p a s 3/2 will come with We have 2 paa so it is working now What does maths say? Pi to Pi cancels out to Pi if se to cancelled then what is left na aa r * aa aa 2 r spa a s power 3/2 in spon So we have these dangerous beasts As the formula has arrived which looks like It's very big, very strange, but the formula So this is it now when did this formula come good here r is the radius of the loop but What is A, what is the distance from the center is where you put this at the P point If you want to remove the magnetic field, then it's ok Keep in mind now if again number of turns is n Is for n turns and now we are very interesting going to do something if there are turns What will be the magnetic field? The power of 2 r scan p as in spon 3/2 I understood this, but is this formula come on check it out right Listen, assume that I follow this same formula The previous formula is going to derive hmm the previous formula means a circular loop I am going to derive the formula at the center of if I am here then this should come answer now if I am here now I am here, okay, now let me come here slowly come here a will be less a will be less a less less low low low low low low low low low like here here a will become zero so if I If I put zero in place of , it means I am here and if I mean it here If I have gone then this formula should come Let's check if the value of a is zero If it goes, it means where have we come at center of loop at center of loop a if the value of a has become row then if If that is the case then I will put it in place of b here If a has become 0 in n i step then 2 r step to the power of 3/2 this cancels out r s since r got cancelled, if one r is left then come gone n/2r now you tell me what is this The formula is the same which we derived earlier If I did it then the answer is exactly the same it means when and how many maybe two or three in bar board paper and bhaiya pre There are many things on the boards and in school papers. time has come that first the axial point The magnetic field for Take it out and with the help of agile point, If you remove the center magnetic field then first this we are doing derivation then we have to say if we The derivation ended here, then It is said that even if you take it out from the center, a will be 0. and a becomes 0 then this formula will come If you understand then this is very important Both of them have very good formulas Very important formulas and exams Let's come now, this topic is very easy We are told that in a circular loop How to determine the direction of magnetic field If you take it out then again there are two ways right I have taught you the hand thumb rule If you have a circular loop where Rap your finger on the current flowing through it If the thumb comes then the thumb will be in cross direction When I came in, this magnetic field was formed and If the current is flowing anticlockwise then You have to wrap your fingers like this here Magnetic field on dot mean You can also outwork it and write it in English If you want to write then if we wrap the fingers of the right hand in the direction of Current then the thumb will point in the direction of the magnetic field at the center is simple There is no answer from clock rule and thumb rule the changing clock rule says that if Current is coming clockwise in a loop Clockwise, the face that is there is towards you The South Pole will be formed there, see, it is the same thing If going clockwise then magnetic The field is in the cross, it's inside and Do you all know about the inside of a magnet? If the magnetic field is from south to north then The face which will be towards you is South and behind you The one that will be built towards the north is Obvious Sea the thing is we are going to use this no but if I run it the other way round that if The current is flowing anticlockwise so whatever is in your If it is facing towards the side then it will be North i.e. behind South will be formed and the magnetic field will move inside It is from south to north i.e. outwards If she comes you can talk like this or give answers like this You will get the same, I think it is God's will You're going to use more To find the direction of the magnetic field No one is asking for the definition of any rule Come on friend, you have grown up a lot but Yes, I will ask you for directions though, rule I won't ask the definition of Let's go again like Gauss law has come, now ampere circuit is coming The law will definitely recognize it and read it but first revise it back and forth Let's go ahead, now how do you understand Gauss Law? Let's understand Gauss What was said in the theorem Gauss theorem It was said in I that if we revise Gauss's theorem do that brother who is a daddy it is equal is q by n now such that is flux basically now like doddy a means It used to be surface integral, that is, any to something like an electric field Integrating it across the entire surface like this here You will find a new word here which is What is a linear integral or line integral Please understand the statement, there is correction in it too is the line integral of the magnetic field Surrounding closed loop equals to the number of times the number of times the algebraic sum of current passing through the loop product with product with Or in simple words, like there. ds9 ba n tha here pe line integral of The magnetic field is now the line integral of magnetic field means i call it d a I don't want to integrate it with d A That means that we have to integrate on the line This was for the surface, it was for a loop if it's gonna b.d. what should I call d the line integral of the magnetic field is going to be equal right times n times how much current is there in the whole loop around whichever loop it's going across We will apply the Ampere circuit law which we call In short A also says that if there is a loop let us suppose there is a It's an imaginary loop, suppose this is a loop right now You will see what it means now. There's a wire going from here and There is i current in it so I will take i here Now suppose two wires are going from here in which i is the current so here i is 2i I will take it, assume there are three wires going here in which there is i aa aa then I will take 3i like this Just see, assume that I am going from here and if this wire comes back then come too it is happening and it is coming and going so here we are You will understand that also if you take zero Karan but the The point is that there is 1/0 of the net charge times was here net current k times and because here also we have a closed loop So here we are going to talk about If you put a ball on us then how will it be done I will read it again, I will understand it, I will read it will read that the linear integral of The magnetic field is n times the net current thread ning the surface if this language is understood If I am not able to speak then I will learn another language I write down that the line Integral the Line Integral Off Magnetic Field for close surface or loop for close loop is n times is man times the net current mind times the net Current Thread Ning The Surface Man Times The Net Current thread ning the surface i.e. n times How much current is flowing through that surface how much is that surface tearing apart that loop or that is, he is threading it Let's understand this, but before that Going to prove it now, big laugh The thing is, if you open NCERT then One very funny thing is that Ampere's circuit law proof of we're gonna do a straight with the help of the magnetic field of the wire and the same The magnetic field of a straight wire is called Ampere will also derive from circuital loop This is not the first time you are doing this, if you If you remember, Newton's second law and With the help of Newton's third law you can find the law Formula for Conservation of Momentum I did derivatives in 11th class and then law of conservation of momentum and Newton's law of motion You proved this using the second law that the third law is present in the second law itself, so It is okay but there is a reason behind it It is to be noted that Ampere's circuital law Actual proof a little You will read it after getting into the complexity but for now For a straight wire we calculate the amperage we will do a proof of the circuital law and then For a straight wire using the law The same magnetic field will be generated again So you have to understand this thing more on this don't focus here we have a wire and Inside this wire let's say aa amount of current is going out aa amount of current is going out Now I have to prove Ampere's circuital law If I have to do it then what will I do I'll take a loop around here I have taken a loop now because this loop is imaginary so I am making it dotted it is ok No Now here I have this small thing at this point I took DA, okay this is what DL means this is the amp loop that I have created imaginary I have taken the loop above it and I am going to use the ampere circuit If I want to apply the law then here is the wire and This point makes it smaller than the lettuce. If the distance is far then how can you prove it? I will do it brother look carefully what are we gonna do guys b.d. dl.ed I will do the integration of a theta now b will come out from this now what will be left inside Let's understand this first let's understand theta d is the length element of this loop now If this loop is clockwise, like if Suppose the current is flowing like this then the right hand Wrap your fingers like this according to your right hand if there is, then there is a magnetic field inside and that is I can also take dl8 even if I take it like this I can because this is the dl2 element of the loop So the length can go like this as well as like this So for now it is wire and magnetic If the field is such that dl2 is and the magnetic The field is also there how for a wire The magnetic field is there and d is also there he is roaming around, look at any point The magnetic field will also be here and will also rotate here must be the point which is magnetic The angle between the field and d is always If it becomes 0° then it will come here dl01 is now a straight wire till now we have used magnetic did not derive the field formula which We will do it but we are not going to use it here. are going to and 0i / 2pir Now we will prove it that With help that's what I'm telling you it's a mess but Actually this can be proved in some other way also it's done now what's left inside dl1 We have I will do dl8 If I do dl8 then this whole sphere will come and What is this whole sphere equal to? So the answer is if equal to 2pir then 2pir cancels out to 2pir It's done, you can understand who this equals brother 0i is gone then b We have proved the ampere circuital law here. It has been done but we have proved it Using a Straight Wire But Actually Till now we have considered the formula for straight wire A. I haven't done any derivatives and that's our amp Our first step in applying the circuit law The application itself is that we are a straight Magnetic field extractors for wires but don't feel bad about it that this Don't say that I have started doing physics like this now no no no its actually someone else formula developer of grown up style Now we will again do the law of state wire But this time we need the formula of state wire do you want to derive it or not and use it Which law ampere circuital law value is to be done Let's see, the current is going up, again same thing is the current and again let us assume that here we have an imaginary loop happened that'll help us get around that We can apply Ampere circuital law, right? If I have magnetic for this at this p point If you want to find the field at point p then this r Is the radius okay or is it the distance When I went here I saw a small thing somewhere I took it like I had taken it before, again You can write the consideration if you want. can you write your consideration let's take it straight Wire carrying current I in upward direction End Taking the circular ampere loop off Radius is smaller R than D is the length element off the loop imaginary loop ok na come on If this is the case then now according to Ampere Circuital Law Ampere Circuital Law in a manner BD is equal to man times the net current thread ning the surface now i in place of bd a I can write bda cos theta n times now this whole loop How many times is the current cutting through then answer is If you are tearing the barhi then instead of aa you should say aa and here in place of theta in cusp theta what do we have to take 0 degree same region do you know is it the same region brother because Here, if there is d, then the magnetic field for this it will also be here that 0 will become one b come out will go inside will be saved dlp.ac.in I know it's funny look I told you I told you beforehand that this will seem a bit funny yes you know but this is actually not funny Because we cannot raise him in any other way I will try to drive it but for now, yes Now very similar to Formula One Straight the wire and the center of the circular loop which is behind We found the center of the circular loop The formula came up with 2r but a Pi also comes in divide for wire, this keep this in mind don't make a mistake it's done It's done, let's get here now I think again this is a very important derivation In this chapter, most of the derivations are If I look into past history, I have come So the maximum has come in parallel wires which we will now read further second most More derivation is torque on a loop and The third highest derivation is a solenoid field of a solenoids You will also calculate the field, okay? Everyone also studied solenoids in 10th class The field is drawn and you all know it that a solenoid's magnetic field once is like a magnet but if you forgot If yes, I will draw it for you here yes it is not a problem ok So here's a solenoid a solenoids It is made of wire I have one Solenoids You must have felt it and come back from here after roaming around it's okay now a solenoid field how does it go if I have this terminal Obviously it is a positive thing to connect with That's why Karan came back from here I got negative result, I studied in 10th where connect the positive where the positive When we connect it, the South Pole is formed there. and where we connect the negative You must also know the region where the North Pole is formed Because the current flowing in it If he is going like this then according to the right hand If the magnetic field is like this then this South this is north and there is magnetic field inside Now whatever goes from south to north is inside The magnetic field is uniform It is straight wire type How can you see the magnetic field from here? goes from south to north but the one which is outside We know that there is a magnetic field It must be that she goes out for a walk The magnetic field that is there rotates The magnetic field inside is something like this Let's make it, there is something outside too and The external magnetic field goes something like this Now the magnetic field outside is So the one outside will go from South to North The magnetic field is from south to north the magnetic field that is outside will go sorry north to south north to south north from south, north, south and the one inside There is a magnetic field, it will go from the south North isn't magnetic to a magnet The field goes inside from south to north and If it goes out from north to south then make an arrow If it is very important then look from here and go inside from south to north south to north and going out from north to south from north south north to south north to south ok yes solenoids like this field makes now on comment section or let's go Think of a solenoid field where is the uniform i.e. Magnetic field for solenoids is Inside the solenoids id is also uniform So you know the meaning of uniform everywhere Now if you look at solenoids If you just look you will see that Magnetic field is only inside There is a uniform on the part but the ones outside The distance between the parts is different Because of which non-uniform will become just like electric field then we people I need to calculate the magnetic field Magnetic Field of Straight Solenoids We don't have to calculate the field, just have to calculate the ones inside because they If it is a uniform then I made this diagram But I made a diagram to explain it to you. This will help us in our derivation Because we just have to work Inside the Solen inside so this is a solenoids I have If it is there then the magnetic feed that will go inside it She will go in uniform Brother something There are some things inside it which are magnetic The field is going, it's a uniform, Arrow makes it Come on, the uniform is going and this is what we need I have to calculate okay now if I If you want to calculate the magnetic field then what am i going to do i am here to do an imaginary will do the loop concurrency because if I have to If we want to apply Ampere circuital law then here like I said here like there gosh surface you have like this here we have ampere circuital If we imagine the loop, here we er circuital loop imaginers what shape is it going to be bhaiya A rectangle or a square shape And we are naming it as well AI hope you can see just this B C & D this is the loop our okay so co and this whole solenoids turns per unit length i.e. one of its There will be A turns in the meter i.e. number of Unit length per turns comes here capital A divide by A like we did thirds Unit on Number of Electrons in Chapter Were taking volume, here the small a means What is the number of turns in a given length Let's write down our considerations, it's very important let us take a solenoid Tech Solenoids capital A if small a is the number of turns on Unit length if small a is the number of turns Unit on Length End Taking Rectangle Ampere Loop End Taking Rectangle Ampere loop a b cd s shone now we will pay some attention brother okay no let's go now this solenoids yes it must have some dimensions so let's I have this dimension from here. And this dimension is not with me. That is, its length became l and width became b It's okay, come on, listen now, brother according to Two Ampere Circuital Law Ampere Circuital Law According to G b the complete closed loop that would be bd0 ta i k is it na the whole of this the for loop which bd0 i's now if that's the case should i do this whole because the loop is a closed loop can I should I divide it into four parts from a to b b from c to d and from d to a Because a rectangle has four sides if it is made then what am I doing I'm doing a piece of it from B to I am breaking bead A from B to C Beading a Piece am from A to B to C so next It's done from C to D B D A and I'm doing one hoon d to lake A Daddy and this has come times the total current dung surface now you see here i have closed sign is removed as in Again Gauss Theorem I used to do it because it's not closed anymore Now here we have to talk about each wire Come on now, there is a very important thing ahead The derivation we have from a to b so the length is on the bottom and the magnetic The field is angled like this, it's a 90 degree angle 90 Plus B to C BDA come let's talk If we talk about it then I am going from B to C. Here is the length element I'm going here and This is the magnetic field, the angle is 0 degree angle is 0 degrees plus c Let's talk about d again from c to d above The magnetic field is at such an angle that it is 90 Angled 90 c to d angled 90 end Last, this one outside, from d to a, this just outside the mag just outside the Solenoids id is there but where is this loop outside now if this is outside then it is outside We have calculated the magnetic field ourselves anyway Ends just outside the solenoids also the magnetic field just outside the Solenoids also have zero magnetic field and We are not interested in that anyway If you are taking out the insides then this is anyway It became zero and came here 0 Times the net current thread ning the surface now cos1 means the scene from 20 to c is left Went bd0 if one happens again then here it comes 0 Times the net current thread ning the surface now From here b came out because I had to go to b Just have to take it out now If I integrate from here to here then I will get l will get no length how much length will i get I will get it bhaiya. No, if I give this If I integrate, the length I get is She will go and get it. No, B had come out. If I integrate a d a d a d a d a then this you will get the full length which is l not which Is it true, come here now, this is a very dangerous scene Now the current is going to come from this solenoid It is difficult to understand how many times it must have been torn It's going to be interesting, come let's understand How do you want to imagine it brother first of all The thing is you have to imagine that this is that AB CD is the loop A B CD is the loop ok now a solenoids It will take 5 minutes and then the kids say that one shot has grown up look son now like this is my ab cd loop ok and these are my solenoids [Appreciation] there are books and every time the one that is spiral He goes tearing that register and then this in the case he's going to tear apart so if every In one, current is coming and going, it is coming and going If current is flowing in each one, So any number of times it must have been tearing the surface How many times will the current pass through it now If brother is tearing then the answer is number off We will use turns here. Come let us understand, listen carefully come in one so if we look at the total, how many times Bhaiya he is tearing apart, he is totally tearing apart, accept it number of turns is into i will become did you understand that this is the net current if you look here If you are getting confused then write I net I Write down the net I net, write down this total current it happens write this i net ok now aa net what is it so one is going in i how many number of turns is n then from here comes b a n = no now what am I here in place of n in place of n Write the length of the small n number of turns into can i get the number of for how much length turns are needed only for l no I don't want the whole A I don't want the whole A from only those terms whose length is n so here I should not write n a in its place I can because capital n will come number off unit length into length on terms and I have come here so here l no l no It got cancelled and congratulations, the formula has arrived it goes na aa aa oe hoya is it dangerous it's a lovely derivation And the small n here is often used by children who thinks this is a small n number of turns no it is not a small n number of turns Small A is the number of turns per unit length i.e. solenoid field number of turns per it doesn't depend, it depends on this at least in length you have more you would have made more turns if you had at least Create maximum turn in length If you are then you will know the magnetic field You will get more for us solenoids field for a solenoids solenoids as it is Let us understand the magnetic field once And just like that, a magnetic field Solenoids Let's see, come to us once there's a magnet right? now there's a bar magnet One part is North and one part is South so this part of it became North this part has gone south okay now we What will you do if you place a magnet here? It is very cute and bar magnet I'll put a paper over it here okay Now what am I I have some iron here I have feelings okay and here I am where did it go yes I have a sieve here Now what should I do with this iron filling? strainer let the iron filling fall on the sieve here I'll put my hand down so that the joke So that it does not get damaged I have already placed the iron here let the filling fall on your sieve ok now look at one thing carefully and remember it would be that magnetic for bar magnets How was the field now you are an amazing thing Look at this thing now if you pay attention this is big It feels satisfying to me just to see it I like doing this so much I can do it all day long I can if you notice here If you do this, the iron fillings will be exactly the same is sticking to the direction as if our The magnetic field of a nearby bar magnet look if you notice then this happens Our poles became North and South on which The most attracted thing is that you You can see the curves, these curves represent Ours are exactly the same magnetic The field is like that of a bar magnet If there is a magnetic field then we have seen this Fine for magnets come on now let's do this work once again with a magnet let me do it with a circular magnet instead think bar magnets and circular There is not much difference in the magnets Because both have almost the same shape By shape I mean actually what is it look this is a circular means a the cylinder is a magnet sorry and this is once It's a magnet, what difference does it make now? take a look i don't think so much It should make some difference but once we Try it with a magnet because its North and South are the same, right? so you can see that it's almost like I also said This also has the exact same impact The same magnetic field is formed here as well as in our bar magnet No changes were made be it North or South This magnetic field has become stuck, really there is no change I can't see it okay so now we Let's talk further and further the motion will be set off a charged particle in uniform magnetic I think this field is a very good topic that the formula we are going to study now This formula does not require any derivation We have very few such students in 12th class There are formulas that don't even come from definitions and we don't even need to derivate them Like the power formula in the last chapter Work was done upon time and it was done now The work which is done on time is by definition It has come, right, but we have not seen it yet did you prove it or did you prove it to be i sr like this only q = But all other formulas for c are n a / d is it done or 4 pa aa n it has happened we have all this derived it but this formula is There is a definition and there is a derivation of it but we I don't want to study in 12th class but before that Understand what this topic wants to say so far what were we reading that we had a There will be a conductor whether he is straight or Whether it is a circular loop or a solenoid field but now we will move on to the second half of this chapter we are going to go to where we are going to read this that if I had a uniform Magnetic Field is already magnetic in an area Suppose there is a magnetic field in the room field and if there is a charge in this room a charge came running a charge came running If force is applied beyond that then first we understand Why would it be necessary if a charge runs away Look here's a charge and he's running away It is running here, assume its velocity is v So does that charge emit electricity around itself? Yes because it will create a magnetic field The escape of charge means current is a type of since he is not running alone in the wire Suppose he is running around you what will it produce in the normal way Assume that the magnetic field is around you now What is creating the magnetic field now? Further into this room there are more magnetic fields is present, then when this charged particle moves its its magnetic field from its own magnetic field If one enters the field then both of them will be in the same position will apply pay force i.e. the one who What is the magnetic field and what does it apply to it? Now the force will do that, how much will be his loss You have to read the formula and by its formula All other things are up to you to judge, okay? What does the formula of force bring to us Then the formula for force comes down to kawhi cross b formula comes kawhi cross B And if I This can be written as a cross product If I remove it, the formula will come with Kavi B sign theta then the formula comes kavi b cy theta The formula of force will come to me, poet san theta which force is this force on charged particle ch is moving with Velocity v in uniform magnetic field So what is the Q here brother, it is obvious. Is charge on the particle which is running away what is the charge on it if the charge If it is zero then no force will be applied v what is the velocity of charge if he is at rest he is not running away So you all know the first part of this chapter I had read in the line itself that when the charge runs away only then it creates a magnetic field now if The charge is not running away, its velocity is zero, then it is a magnetic field will not make it and no force will be used Obviously C is the magnetic field in Surrounding Magnetic Field in surroundings How much magnetic field in the surroundings You applied and again theta is very important because this was v cross v so whose theta is this is the angle between velocity and magnetic field so this is theta angle between angles between Velocity and Magnetic Field Angle Between velocity and magnetic field then this angle What is between velocity and magnetic If the angle between the fields is then this formula So we have to read it but there is no derivation of it If you don't want to do it then remember this formula The formula for force is q v cross b That is, q if it looks perpendicular to the velocity then it by changing the direction of its velocity could but his Magnitia If a charged particle is in a magnetic field I also enter it, suppose any He does it at an angle as well So even though the magnetic field is a force on it It will be installed but you will be charged for installing the floor just by changing the direction of the particle you will find it because it is always with velocity there will be a perpendicular front and if the direction If you can change it, that means you His Magnetia: You can apply a magnetic field can't make his velocity 12 no 13 can eight can't you just what You can change the direction and that is a lot This is an important point which you will not know much about right now. I am going to write it up, but before that we will read three different cases that brother if one There is a charged particle and beyond that there is a force We have found the formula, so that force how much will we get oh oh oh oh so that How much force will we get now with its help We are going to read that in three different cases Which will be made then the first case is when a charge Particle enters parallel to the magnetic field will do now let's imagine that in this area some magnetic field is going like this okay No, there is some magnetic field going towards this This is our magnetic field in this area That's done, okay, now if this magnetic field is the uniform magnetic field b and Our charged particle is a charge called q. The particle enters it like this: v So how did it enter with velocity? If I enter parallelly then whenever any parallel if we enter then theta will be either 0 degrees Because he can enter like this also But parallel means that it can also be So theta can be 0 degrees And if we look at it, Theta can also go 180 degrees Maybe it's okay now with the force We have the formula q should I keep it vb0 or 180 then 0 is also 0 and 180 is also 0 This means that if a charge Particle in a uniform magnetic field If it comes parallel then there is no force from it It will feel like a magnetic field It doesn't matter if it happens or not He will go away the same way he came If further changes are not coming then this is the case It is very simple but the most interesting case and again very important case and again The case on which many questions arise what we have here is that when a charge When a particle enters a magnetic field will do it but how will he enter it He will enter perpendicularly, let's understand now an area Let us assume the magnetic field in our Let's assume for now that the pass is inverted where do we have the magnetic field invert invert so we have this invert There is a magnetic field, why should I invert it? I have been this The first time I took the right from the left Again, first of all it doesn't matter but if I invert or So I will explain the motion to you but if I take the left or right then the diagram it will be made in a way that you will understand it will not come so it is best to invert or Outwork Field We the People Meaning of the Cross has inverted uniform magnetic feed I have taken the inside page or say inverts okay now if a charged particle if a Charged Particle Let A charged particle named q has velocity v in it okay so the first thing is this Will the force be applied or not, then the answer is If it is entering perpendicularly then theta will be 90 th 90 how did it become magnetic The field is an inverted magnetic field what it is is invert and the charged particle is like this If he enters then it is obvious that he The angle in the middle will be 90 The magnetic field is inverted and can be entered as then the angle between them will be that will be 90 degrees and in 90 degrees The formula of force will come to us poet I'll put b theta in place of theta 90 and we all know that it is 90 The maximum value of f is one and its Meaning the force that will come to us is theta that poet who will come with respect to It will be maximum it will be maximum because san The value of can be one maximum Leave aside the maximum and the minimum, at least I have understood that Force will be used and how much force will be used poet B How much force will be required poet B now this force How will it affect the charged particle Does it measure the velocity of the charged particle? will it increase his magnification will change the direction, come let's understand now It is certain that whatever force is applied will How will the perpendicular to velocity happen now? It will happen and please pay a little attention here What will happen to you on this charged particle Magnetic feed is inverted yes is it on this Velocity is here and the formula for force what is that we have of the force the formula is we have q v cross b q v cross b this is v this is b then charge The force applied on the particle is q v cross b so if this is v this is b then v cross b v The force will be inverted according to the cross b If the magnetic field was outside then how would it seems this would have become v this would have become v so v cross b v cross b magnetic for now The field is inverted and if you enter from here then It will turn downwards, I will do this to you For making it more understandable, I am here enter the charged particle from here is perpendicular entering from here this is a charged particle and this Entered perpendicularly, its velocity is So here we have the magnetic field This is the velocity now if v crosses b If I do this then will the force be applied down guess yes now this one was running here this one running this way with velocity v But the direction of the force that has come on this The direction of the force came down and we I have been studying since 9th and 11th class also force is perpendicular to velocity It moves the object in a circular path it means brother the charge from here The particle was running away and the force was applied beyond that down below so it goes like this in a circular path it will start rotating and it is obvious that if Next there will be magnetic field in the whole area Assume that the magnetic field is on the whole board then it starts moving in a circular path He will go and keep roaming here and there will keep rotating if the whole board is magnetic if there is a field then if not then come out from here It will happen but for now I am assuming that it is The charged particle moves in a circular path why would it start rotating because this floor yes she is perpendicular and which farce is she will work like a centripetal force And if you turn it around then it will be a very interesting case Now if I put magnetic feed in it like this If he had made it and moved around like this then he would have been able to understand that If we made it like this then the work is finished here it does not happen because we have understood that the because the force is related to the velocity If you are looking perpendicular then charged particle If you are going to travel then write a line here will have to S force is perpendicular Two Velocity So charge Particle Will move in circular path if it will move on a circular path if this If it moves on a circular path then its radius will be There will be some time period, we will also I want to take it out okay come on let's go so if it is like this So its centripetal force will be because it is rotating centripetally It will get force due to magnetic force from which here q is also centripetal The formula for force is mv2 / r and The magnetic field which is fitted on it seems is being qb1 v is cancelled then mv2 came so from here if I use radius I want to find out the formula that how much will this be If it rotates on the radius then I have the formula it comes to in mv1 the q b v formula comes to me is avi in your q b and if your preboard or whatever mid-term papers you have done and if A chapter was coming in them so you too knew this You know I also know that Bhaiya is at 90 There is a top score above this in the children's exam A question may have come, especially what kind of question? a proton is a neutron is their velocity I know the ratio of so and so I know the ratio of this If you know the radius then you will get many questions like this and if you attended lectures in 12th I had asked a lot of questions about this If you attended the lecture then I had asked questions above but did not do it live So as soon as the one shot is over the live session Please go and check on Sunday at 12:00 am in which we discussed the third chapter and I took the fourth chapter, so for now this we have radius mv1 in q b mv1 do I understand this now what else can we extract from it so we I also have to find out the time period now That is, when it moves in a circular path then How long will it take to complete one round We are calling this a time period, so time What is the period formula? A round cutting distance watch is 2 pa aa upon me Its velocity Distance of one revolution Upon me is her Velocity is 2 Pa from here I am r I have removed it, then what should I write in place of r I can write instead of mv9 b r mv9 b divided by what is it brother velocity Velocity to Velocity got cancelled Time period formula is available in 2pm up q And the more interesting thing is that the Has the time period formula come or frequency formula if because Frequency and time period are related to each other If there are procal then the frequency if If you want to withdraw money which happens one time then The formula will come in qb yours at 2pm but Keep in mind that if over a time period Let's talk about it, many questions come in the exam that shows that when ever a charged particle Enters in uniform magnetic field time Period Remains The constant or time period is independent of velocity if I take a particle from here If I throw it with velocity v then it has a There will be a certain radius and if I double it I throw it with double the velocity so its the radius will also double because Radius is directly proportional to velocity i.e. if I throw from v then the radius r is 2v If I throw it then the radius is 2r but it has to be rotated It will take the same time, hey, please understand the matter If you are going around like this and I am here I am spinning in circles if my distance from you is it is double but my velocity is also more than you If it is double then both of us will be at the same time will arrive means the time period It has nothing to do with velocity The time period has no relation with velocity Time period constant has nothing to do with it remains for a particular charge in Uniform magnetic field and this exam I come here a lot, I understood, let's go to the next one here. what did we do we can make a charged particle We brought parallel forces but no force was deployed here She applied force but she was perpendicular did you change the direction of velocity But what did he not change? Magnitia off velocity off Charge Butt thorn Change Magnitia and if Magnitia m is the mass and mean square of the velocity there is velocity Magnitia does not mean that if a charged particle Now you will show us the proof as well We will do it, there is a very important derivation too But if a charged particle is magnetic even if he enters the field The direction will change, even if so and so changes the drum but his magnanimity changed the kinetic energy of the charge will not come Only the electric field can increase The magnetic field cannot increase because of this There was a great topic above called Cyclotron The last 2 have been deleted from our syllabus It used to be available a year ago but now it is called cyclotron. The topic of the name got deleted, well when Initial velocity makes an arbitrary angle any random angle with the direction of Electric field In the first case, we People brought him parallel second cases I brought him here Perpendicular now third Brother, it will be fun in this case because we're going to get it because we're going to bring him a random at any angle a random at any At an angle, the magnetic field value for us is look she is going here here here here here it's okay Now our charged particle which has come this time If he comes like this then there is no force It will seem that if you come like this, you will move in a circular path But if a charged particle is Suppose a charged particle comes like this and He is making any random angle theta which is between 0 to 90 ok so what This velocity will break into two pieces yes This velocity will split into two parts this is the piece which will become v cos theta and a this will become a piece this will become a piece which will become v psi theta now to understand what matters is the piece with sine theta Is it perpendicular to the magnetic field? and the piece that is perpendicular is moves the charged particle in a circular path like the one here with san theta the piece is there and above and the magnetic field like this so v cross b v cross b so what particle this is v this is b this is theta one what am I talking about this is this is b v cross B so where did we get the thumb inside That means force will be deployed, he is running inside here If force is deployed here then is it okay to roam around like this? You understand that the force is running away here Will this charged particle hit here? Who would like to roam where would like to roam we have v san theta who is this we have Magnetic field v cross b looks like this There is force and it is going like this, then it is going like this Would you like to roam around like this, tell me friend, but what this theta component of v, which is I would definitely like to take this further We have velocity, I have it There is a magnetic field, now it seems like this Velocity is this force, charge it like this Let me show you the particle from the front I must have got confused about this This is theta, this is the magnetic field. if it is like this then you are going to pick it all up If I bring this magnetic field in front of you It's done, what's coming towards you, it's coming magnetic field this v sa theta then v cross The force from v was applied like this now leave it now Who is this? I have velocity and force here. So it will rotate like this, it will rotate like this means it will rotate like this means it will rotate like this This is how it will move around in this plane Now this is the theta component it would like to take it further sa theta component it will rotate and the theta component will move forward Look carefully, the theta one will take you along He will say, turn around son, turn around like this, turn around like this turn like this but the theta one will say move forward So if he listens to both of them then this It will rotate and move forward, it will rotate And it will go further, it will turn around and go further will go and which path will it make, the answer is like this who will make the path, which path will it make, it is like this dear there is no numerical etc on it no one remained silent, no one was numerical No derivation like there is a formula here Numericals will come, many more will come Derivations also come, conceptual ones also come but there is more to it than just this I will ask you which path to follow You will learn English a little bit, write it down I want to write quickly by stopping the velocity I will say okay as velocity is making Angle theta with uniform magnetic the field cos theta Component will tend to move the charge particle in forward direction and sa Theta component which is perpendicular to The magnetic field will tense to rotate the Charged particle in circular motion has due to both the components the charged particle will move in like path forward in direction lickal path forward in direction is done and Then quickly make a diagram. because we're here to put on a show Kinetic energy is constant oh brother Then a new phase is going to start from here too there are still many chapters left There is lot of derivation in this chapter You can see that each derivation is explained It is taking me very long but I am sure It seems like a little tall forest is going to be worth it It would be a shot but it would be worth it I saw it One shot of magnetic effect is very rare are embedded with proper derivation Every little thing has been explained Make a diagram quickly, then move on Let's move on, okay brother, let's talk now let's figure out how the kinetic energy is We have discussed overly that whenever a The charged particle will move in a magnetic field then the kinetic energy will remain constant but How can we do its derivation? Come on Please understand brother, the first thing we all We know from 11th class that if A and I are two I perform the dot product of vectors such that If you are perpendicular to each other then you will get zero Dot Product of Perpendicular Vectors what if it is zero The dot product of force and velocity it will be zero why because the force he is always perpendicular to the velocity We just talked about this earlier and two more Dot Product of Perpendicular Vectors is always zero because a vector b The vector is theta and the vector is 90 zero so from here I can write in place of force I am mass into me I can write acceleration bhaiya, I can definitely write it and I can write the acceleration as am dv It's a bye brother now I'll give it to you I am dividing by multiplying by two so that I am doing it, you will understand it, then divide it by T brought the v forward and to multiply by Now you watch carefully as we drove because if I look carefully here I have m div ba 2 and this is 2v [music] If you do DVD-R, it will come and vice versa. So this is what will happen, here we people Basically I wrote that v sba dt2 will move in if m weight is moved in went then 1/2 m v sba dt50 is done now what is this It is kinetic energy, yes brother kinetic what is the energy for now Differentiable means kinetic energy Sorry sorry sorry something that is constant is his The differentiable kinetic energy is constant which we had discussed orally as well but Here you can prove it mathematically also. you can do that when any charged particle even if it enters a magnetic field You might be feeling the force on him but his The direction will change but the velocity will there will be no magnitude of and if he does not If it happens then what will be the kinetic energy Let the force on a current remain constant Carrying conductor in magnetic field is now easy If a charged particle is magnetic Enters the field and forces it If the entire conductor feels I will put it in a magnetic field then force will be applied now if this diagram If you remember, we have this diagram has read when we were in 10th we had this A Horse Tew Magnet at IMDb here we have a horse magnet Whose north is here, south is here ok we have a rod lying here hai rod now this is an aluminum rod if then Aluminum rod attracted by magnet it doesn't get repelled right so this is something there shouldn't even be a Stand and with the stand we put it here but positive here negative and from here The wire went The wire went here and from here to here, now as soon as we People had a switch here, they turned it on if you do this then this wire will come out of this aluminium rod The current started flowing and if this When current passed through the aluminum rod, we did you see this rod started moving now it happened what will happen first thing the topic is saying that If you take a current carrying conductor such as a rod which is made of aluminum, current passed through it So due to the current flowing, a force is applied on it But why did this happen to a current carrying conductor But we need to understand how the force is applied I might have done it a long time ago, maybe today 6 years ago 7 years ago A bipolar motor I had made a video of that motor for you here Let me show you how when we use a magnet running current around are in the magnetic field of a magnet How to place current carrying conductors A bipolar motor can exert force beyond that and all the motors in the world work on it When we talk about torque here If you do it then you have to read it also but for now For this you can understand it very quickly by watching a video This is an old video but watch it once [music] [music] [music] So rough you saw that as soon as we When that loop was inserted, there was a magnetic field The cell completed the circuit around the current The carrying conductor came in contact with the magnetic field There was a force in the middle and it started rotating so why did it turn, that is the torque, that too we will read but yes whenever a current carrying The conductor is placed in a magnetic field it looks like a floor on it now you can put it on the past You can surely relate it to the topic that Brother, when a charge comes into a magnetic field if it is happening and force is being applied on it then Charges are flowing inside the conductor as well If they are there then a force will be applied on them as well, now a current will be applied How much force is applied on the carrying conductor we have the formula for this which is a b this is aa aa b this is l i b If you want to log in to sins.com then let us suppose we have a wire here okay This is a wire of length A from the let and its area of cross section is a okay now in this area now out of this There must be current flowing, yes it is current It must run if the current does not flow Brother how will this become a current carrying conductor So let's assume it's running in this current and in this area you will get magnetic The field is given B which lets say A like this I'm going to make one for now and magnetic The field depends on our current along our length the angle it is making with itself is theta so First of all tell me what force will be required yes because you have used current carrying conductor is kept in a magnetic field why would it affect Because this is the conductor, this is the conductor It will create its own magnetic field and There is a magnetic field outside as well, so this both magnetic fields are opposite to each other Will interact Will attract Will repel Because of which force is applied on each other gonna do something like this Now if I understand this, then I will take another I am going to lay down something here n I will lay down I am going to do it n what is the number of electron is the unit volume here No, how many electrons do I have per unit volume which I also during Ohms law I was late, you must have been late too What is the small n number of electrons Unit volume consideration you can write let us take a conductor of length small a Area of cross section larger A carrying current Capital is kept in uniform magnetic field b making angle theta with the length of the wire if small n is the number of electron per unit volume then if small n is the number of electrons per unit volume down now listen from here we are Do you know the formula of force The formula of force is this q v cross b okay accept this first Equation Now will you take out the charge from here? will be the charge how many electrons do you have number of electrons in this whole bar and every the charge on an electron you do you know what happens if you are negative Log in with the sign so ok how to charge it again We will extract the charge on each electron - e Multiply by how many electrons you have Now we'll give you how many electrons so the number of If you want to remove the electron then put it into n I will turn up the volume and take out the minus And here instead of number of electrons we use n Volume Tax Into I will give it to you ok now what is the volume of this If this is a cylinder of wire, then I will calculate the volume I can write to a volume I can write a volume If the cylinder is e then this is the total charge for me It's done, you understand this much, now if the total charge This is done if I consider the second equation I take it then Putting Second Equation in First Second Co put it in first if you do this The formula of force will come to me q I have put it in place of - in place of n q I have put it have put it - n a - n e who is with it l but who is inside me v cross b now Listen to this step carefully, I hope you like it you know if I bring v out and I want to take you inside If yes then this minus will become plus in maths The rule is if you put one in the cross product If you want to take one outside and one inside you have to put a minus outside so if I'll put a minus here so minus minus will be plus n v will come out and go in l cross b b is the same l went in v came out do you recognize it hey do you recognize it hey Do you recognize the third chapter i is equal to what happens to D it comes i kas b means we have done this No derivation of the formula was done but its derivation is i cross b We have to do it properly and if I If I write this in angle form, then i = b When will theta reach its maximum i.e. when Now it will be necessary to remember NCERT in 10th class There was a question that if a current carrying place the conductor in a magnetic field So when is maximum force applied then this is the answer You were made to memorize that the maximum Force is applied when the current is carrying conductor with magnetic field If you are lying perpendicular, today you can understand that if it is perpendicular then why maximum Because the angle we have is theta We will have that 90°, got it done. Any problem, any problem is gone for sure Come on, come here, I told you about this chapter ki second sorry actually first The most important derivation we will discuss here is We are going to the most important address first no why look at me i would be this one that derivation is useful in our practical life It is very useful so it comes in the exam also as discussed later in this chapter about torque The torque will be checked on the next page If you have limited space then I want to write a page here And you will have to add it after pausing the video but For now if I have this derivation I I will tell you what I am going to do now but this The most important derivation of this chapter is It comes the most in the exam, let's understand what does the expression want to say first for force per unit length between two infa Night Long Straight Parallel Current Carrying Wires and then define amperes etc. It is to be done later, in my opinion That's a later thing, okay let's see it first understand what to do what to do this is a Wire Is And here is another wire that I have, okay? ok one more wire is ok current is flowing through it it is coming please accept it Come on and current is going in this also let's say up but towards magnitia Will you apply pay force or not? If current is flowing through them, then is there a wire on the other one and this wire on this one Will you apply force or not, come please understand what the first wire is the first one Is this wire a magnetic field? It is obvious that it will create The first wire has a wire around it The magnetic field will be exactly there and Its magnetic field will be this the wire that is creating the magnet field in the form of consent circles which are at the back We have also calculated its formula isn't it, come let me get 2 ah this wire here is named b1 would be producing a magnetic field and this What is the magnetic field of the second wire? It will be across, yes it means the second one The wire has become a current carrying conductor whose Magnetic field is kept around first The wire itself creates a magnetic field around it will produce it by doing this because of which seconds There will be a force applied on the wire because whenever A current carrying conductor is magnetised It is kept in the field and a floor is placed over it If it is there then we actually have to remove that force Now we need to find the force per unit length. Use your brain, the second wire also did the same What would you have created for yourself, bhaiya Magnetic field and its magnetic field what force would you be applying on this but avery action has equal and opposite reaction so we If you remove one the other will come automatically but How much force will you be applying? can you write the consideration let's take it parallel Wires carrying current ive at in the same Direction Abhi will read if opposite what will happen if he is going in the direction carrying current ive out in same direction having small distance between the wires then now come here pay some attention Suna Magnetic Field Magnetic Field produced By Wire How much magnetic field is generated by one wire If the magnetic field at that D point is We have read the formula of Aa Aav because current is flowing in it upon 2 pa means r means distance and here It is obvious that the distance from it is d So 2 padis came and it came to us Magnetic field produced by the first wire around second then How much is the force on wire to wire? What did we read about the formula of force? Just read ALB Sine Theta Meditation today The thing to be heard is that it was a current who is running in the conductor then The current flowing through it must be taken is aa2 is the length a but the magnetic field is that happens around it and around it The magnetic field is b1 and the angle If we talk about it then it would be 90, understand this much how would you have gone, this wire is this It must be making the magnetic field inverted There will be invert current going upwards magnetic If the field is inverted then the angle becomes 90° or 90 How much does it cost bhaiya it becomes 90 one ok so the phone has come on the second one i2 i2 is our So instead of l b1 I am writing i1 up I am 2pd which came from here now I have to because I don't want to take out the floor If you want to find force on unit length then use l If it goes into divide then f2/l comes here I got 0 i1 i2 up in 2pd no i1 i2 / 2pd so this is our formula So friend, I just got my moy moy just now just now what do you mean this morning I Next to this, I probably made this box last and after that the audio of all the videos it was not recorded because it was in the mic I had batteries and they ran out, so I had to give it all away re-recording the entire segment You are studying this, write it down in PPT I have come and erased everything before this all this had happened had happened had happened So this one shot might be delayed for one more day it will come to you means if you are watching then it will come It is done but the batteries were dead so I I even read to you that this one The magnetic field of the wire is on it The force to be applied is 0 i1 i2 / 2pd It would be so if it is on the second floor The unit length is the same on the first one too the frequency will be 0 i1 i2 / 2pd how can i do this I would like to take out the floor of this one so this The magnetic field it will produce is 0 i2 / 2pd it will be done and i1 will come here so come i1 i2 up has 2 d no the point is that this We will lay equal floors on this one and this one. But here we have written two points The first is that if the current is in the same direction If it happens then these two wires are connected to each other will attract but if the current is opposite If it is in direction then both these wires are one How to repel others? Let's understand this and This is a very important point in the exam Often if a numerical comes above it then At the same time, they also ask for directions live I asked two questions on this in the session I had got this wire done and now it is going up in this If the current is high then my right hand his fingers in and out like this if above so here invert invert invert Invert invert is coming and what is in it what is happening in this right from here If I apply the hand thumb rule then outwork from here Word Outwork Word The outwork field is in the opposite direction magnetic field in opposite direction This means they will attract opposite polarity If there is one north then there is one south which means this Both wires started attracting each other it will go away if the current in the wires is same If it is in direction then the wires are connected to each other attracts whereas if the opposite It will be in one direction and is going up. down in one let's say it's going up in this so cross cross cross cross if in this if it's going down if it's going down If it is inverted in this also then it is for both The magnetic field will be in the same direction If they are in the same direction then both of them will be one If you cancel out the other one then this thing we did it then if you remember then we We want to talk about force, unit length and At the same time, we have to talk about 1 ampere Definition of child often asks that sir If the definition of 1 ampere is stated then I one coolum of charge is flowing through a I can also write conductor in one second you can write but when just define 1 If it is said as ampere then it is said as force but find the unit length and then define 1 ampere then with the help of this formula we People will define 1 ampere, it is very simple See what current is 1 ampere If both the wires have one ampere each current is flowing between them Distance in 1 meter then force on unit length or force What will it be equal to in Newton per meter? 2 pi then what is the current of 1 ampere 1 Ampere is current which flows in two parallel Wires having distance of 1 meter between them produce force of / 2 pa and the The value of /2 pa is 2 * in power of 10 -7 So if two wires have one ampere each current is flowing and between them The distance is 1 meter, so the The force applied is 2 2 * power of 10 - 7 If the meter is applied to Newton then in the case which Current must be flowing in both the warps If it is 1 ampere then we can measure the ampere like this We can define it and whenever history is lost is p y koo check force per unit When derivation of length is done then 1 ampere is also I don't know it has come so much Why does it come in the exam, this is our life Actually, what is more important than this in our life i.e. in our life i.e. daily There is that torque in life, everything in our house In which it starts rotating after passing the current You will find the reason for it here, so this is for me Looks like you are using it more practically yes we are but it is ok in exam this is very So now it comes, what are we going to do? Now we are going to do this chapter Second highest score in the exam Derivation which is torque on a current carrying Loop Kept in Uniform Magnetic Field If I make a loop with uniform magnetic If I keep it in the field then it will experience torque So first of all two of this whole derivation There are steps, first you have to understand that Will torque be applied or not? Will force be applied? no, after that you will read how much torque If it seems so then first of all let's look at its diagram Let us understand again its diagram is very big it is important so here we have here We have a magnet here is going to be the north pole of and on one side we're gonna have the south pole okay So let us show it in white colour we give So here is one thing you now know about magnets A pole alone cannot exist, so here but we have the north pole of the magnet and Here we have the South Pole South Pole it's ok no problem Now if this is north then this is south You know the magnetic field must be going What did we do between North and South? I put a loop in the loop it's a rectangle It is a loop and can also be a square again now for this is a rectangle loop end object It is a strange thing that if current flows through it then Like we talked about in a circular loop here Current will flow like this, wire must be coming from here right now we're showing it like this okay Let's also take the name of the loop, assume some Go, let's call it A, let's call it B let's call it a C, let's call it a D okay now let us suppose in this If the current is flowing clockwise then in this case current is going clockwise current is going clockwise going clockwise going clockwise Jaha So will torque or force be applied on it Let's understand Look, let's talk first that if this loop like this for now right now here there is north here is south here is north south So I imagined the loop like this, and this Because he is going to roam like this in a while Now we will teach you how to talk in this If it rotates then it will rotate like this, like this, like this, like this It could be anywhere, so for now Let's assume at random that this is a certain point I turned around to listen to what I'm trying to say It is going from north to south here magnetic field so it is certain that Magnetic field is in the right word direction so if the magnetic field is right if it's in word direction then it's mine Represents the magnetic field current is going up in it now if The current is going up, this is right, this is up so what is the formula l cross b l cross b A cross B so where did the thumb go inside i.e. that the force is applied on this part of the loop it is inside okay and obviously this one But the current is down and the magnetic feed is such that Even if I cross, the force will come out use your brain, the force is inside this one and this The force is outside if it is inside then it is If he is outside, will he go for a walk like this? And if it rotates like this then this loop somewhere in my it will roam around like this will Ooh, somewhere this loop is going around like this It will go okay now this loop has turned like this By doing this, that means A went there and B went here D has come here C has come here yes na this is turning There was a loop left so I took another one on the way I took a photo of it just to explain it to you Bhaiya this is actually at the same place It will not stay, it will rotate now, we have ruffled it I understood that force will be used in this attack Invert will be installed on it and will rotate due to the outwork But we need to show that this is just will rotate, will not go back and forth as if In the first chapter we showed that a When Dapor is applied in uniform electric field If it is kept in then the net force on it is zero because of which it moves back and forth up and down It does not go down but torque is applied because The line of action is because of the force if it gets separated then here if you If you want to write your considerations, write them down that let us Tech Uniform Magnetic Field b in Area Uniform magnetic field B in area and a rectangle loop a b cd rectangle Loop A Cd Edge shone with dimension small l and small b with dimension l*b Now come here and listen carefully to what we are saying First of all we will apply force on all four How much will come out, I will take it out first Force on a Just read the wire force formula, meaning I taught you in the morning and I will teach you in the evening I'm re-recording the Force we read the formula aa b sine theta so which The wire with A is of length L and theta is How much is it, use your brain, theta will be 90 How is the magnetic field going up here current is flowing then if the magnetic feed is here and the current is high here then how come You can rotate it as per your wish, it will stay on top and will be magnetic If the feed is like this then you can rotate the angle as per your wish How long will it be brother, the angle is going to be 90 Whatever be the degree, the angle should remain here It's gonna be a 90 according to the force on a She will come, she will come, remember this brother Ok similarly similarly If force is on A then obviously C brother, this is a matter which is rotten, come on that too It will just come, the direction is going to be opposite The force that will come on the road will also come because its angle is also 90 just the direction It will be the opposite, like this one, if for now This one was inverted, if it is inverted for now hey where was this one, if only for now she died If it was invert then this one is outward You just have to remember that the directions are opposite Ok, now let's move on to some really interesting work. on whom will we calculate the force Eddie Wire Pay Now Eddie Wire The force on the AD wire will be Its length is b now something here How will the angle be formed from the let's to alpha Look, the current flowing through it is here So this is done for us. I removed it. I will give it to him now, it has become L and magnetic If the field is going like this then this angle will be formed In between these it will be that which changes frequently I am saying this, aren't you understanding what I am saying? I am saying that we have it is the length and this is the magnetic field now his The length of the magnetic field is fixed, but The length is changing now if you look from the top If you look, between the magnetic field and L The angle will change again and again So for now this angle is alpha if this Angle Alpha so I put alpha here ok also the magnetic field that we have below But it will happen, that means if we have b, this If it is c then this is b s so the b s p is ours You might be feeling a magnetic field nearby, that would be will it be a b cy alpha or 180 my alpha you will have to use your brain how to do 180 my alpha here This is l, this is b, so this angle is alpha. this one here is l this is l and this one which that is b if you understand then this angle has to be taken If this angle is alpha then this angle is 180 - alpha It will happen because the direction of the current In this one it is here So in this one it is here So what will be the angle 180 - alpha end The great thing is that SA 180 - Alpha whatever happens is just alpha Alpha is the only thing that happens 180 - Alpha which is it is like alpha, it is like a formula is the length i into the magnetic The alpha in the field into will be here as well i into me the length which is b into magnetic Field and Sa 180 - What happened to Alpha we have the same alpha Alpha is gone so what is going to happen now Look, this is the A force and the one on the road There is force which is equal and opposite now The force will come down from A cross B i.e. The force that comes here will come down here but the force that will come will come up now if this I have a loop so the force here is up Here the force is below so both the forces are one is on the same line of action with the other and If it is opposite then it will get cancelled, right? Brother, is it correct to say that S Force On A is equal and opposite to force on CD Force On CD also Force On eddie is again Equal and opposite to If force is on what is then its direct meaning is The net force applied on this loop becomes The one that is going to be zero means this loop neither going forward nor going back This is gonna loop back and forth back and forth somewhere The net floor that will be placed on it will not go It is zero but will you have a talk on this? Come on Just understand when the talk starts when two are equal and There may be an opposing force but their line of action It should also be the same, now this force is above is towards and this floor is below if it is towards then their line of action is same If it is there then it will not create any talk But this force is here and This force is here, that is, this The force that is being applied is being applied inside and this force is visible outside So is their line of action different? Yes If their line of action is different then is this Edgerton is Edge line of action line of action means what forces are being applied on the line edge of the line action of force on A & Force On CD is not Beans so sss Forces Will Agent torque is what forces are exerted is going to be torque and that is what we need to find out How much torque will be applied then come here what is the formula for torque bhaiya 11 miss class The formula for torque is given here perpendicular between the furthest into distance into between perpendicular The distance here is the force applied torque which floor is it is it's or Seen from above, this is me making Eddie hm eddie this is a this is d seen from above So this force that we have here, There is a force applied on the We have this force applied to the CD So the perpendicular distance between them what happened is this happened right now if this angle Suppose we have theta and this one The width is b so the one in front of it who is b sa theta so here Perpendicular distance will become a sign theta capital b is the magnetic field and sl b is its width then aa is taken apart a inu I took B aside and came together B Sa theta do you know b in l in do you know b in l n area So what if I replace A with B with this Let me write down the area a sine theta comes now this gives us torque if our loop has only one turn if it has a number of turns for a number Off turns for a Number of turns if it has a turn If there are then the formula for torque is aa This is sine theta, I remembered it like this Was Without sign theta is easy to remember Many names will be created without any name [ __ ] sorry whatever you name it If you want to see but there are n number of turns here What is the current in B magnetic field is the area of the loop and theta is This is the angle which is changing again and again It is in the case brother so this torque is If it is applied on one of our rectangle coils Uniform Magnetic to Rectangle Coil If placed in the field, then this derivation It's not easy, I'm telling the truth most of the time Children get confused in the diagram that how did angle alpha come theta came if so So pause the video once and go back There is no hurry to go back and understand again how is the direction visible without There will be confusion regarding direction, it's done Let's move ahead, if you have paused for now I went to the background and saw it, so let's go Now let's talk about moving coil galvanometer that you can say that the moving coil Galvanometer is a type of part of this chapter. a very important This is a topic, I will tell you why It becomes important, listen, look, moving coil galvanometer do not start first if you last P Y cuz if you look at it, it didn't come much It happened in the exam, I will tell you the reason behind it What is reason because earlier in this chapter a And there was an important device named cyclotron so if you have an old book You pick up the one which also has the old syllabus P Y cues then you will get it in that Cyclotrons are available in abundance Cyclotrons are available in It was a very good device, now it is a chapter away There were more questions on one device that's the cyclotron but because now Cyclotron should be deleted from this chapter If it has gone then you can check now or in the last 2 years that the moving coil is placed quite high above the galvanometer Questions have started coming, first thing is moving What is meant by coil galvanometer Do you all know what a galvanometer is? There is a galvanometer which is very Calculate even small minute current can you do it brother one ammeter and one Do you know what is the difference between a galvanometer Is Sabko Galvanometer Galvanometer Can only Detect and Calculate and Calculate Very Small Values of current like in micrometers micro ampere melting A meter is a device which measures very small current not even actually there to measure it Just for detecting because micro You can say this is maximum in amperes The mistake may go in the milli but you think that I can generate 1 ampere, 2 ampere, 10 ampere from this If it is impossible to measure it then forget about 50 and 100 go ahead we use emit for that Ammeter is actually used to measure current Made to measure Made to measure but the galvanometer was made just to show the presence of the current There are also currents which are very difficult to detect which are very small now We have many different types of it Galvanometers are one of them We have a moving coil galvanometer which Actually galvanometers are very different If the moving coil is of the type There is a galvanometer with a coil inside it it rotates first i will tell you about it I'll make a rough diagram to show you Later we will also see it through a video Now what is the use of moving coil galvanometer? On what principle does it work? So what happens is that whenever a current Carrying conductor in magnetic field is placed then a torque will be applied beyond that point and With its help we will extract current if you want So you can write its principle by saying I'll write it down for you to save your time Pause the video and write down the principle what is it bhaiya when ever its a current Carrying conductor is kept in magnetic Field It Experiences Force and Current Carrying loop in magnetic field Experience Torque to Current Carrying Conductor If you keep it then force will be applied and if it is looped then the same force produces a torque on it now it is going to be like this how is it made It looks like this, come let's understand what we have here The magnetic field was taken in a very uniform manner I took absolutely straight magnets here But what actually happens in the galvanometer The magnets are taken in radial direction Magnetic are radial magnets Now what are these radial magnets? I'll tell you, but before that, this is our there is a loop now what happens in this loop brother we are here People now take radial magnetic field as What is a radial magnetic field? This might be a new word for you Radial magnetic field is a new term Like here in North And I took all this with a lot of hard work I had created everything got erased, yes and here But we took it south but this time we took the flat north or I did not take the flat south, if you look at it, it is no we here But say some semi circles of such shape I have taken magnets and the reason behind taking them there is a reason yes that's it there is a reason We will also know the reason, what is the reason There's some reason or the other Son, the fifth reason is also coming here now The magnetic field that will come out to us is it will turn out like this It won't come straight like this and we have We have taken the soft iron core and have left it here will come out from inside and will go here from inside I will go out from here and come out from inside here will go She will go here and she will go here, I am telling you like this But what is the reason for taking magnetic field? Take Now, over this soft iron core, we have The coil is wrapped here, now this coil sorry under this coil here But say it up or down, the meaning is to see Perspective: There is a spring here, There is a pointer to the spring here pointer and here we have a scale beyond which 0 -1 -2 is written like this If this count remains then I will write it later yes it is obvious that there is a proper This is the complete mechanism of the whole There is a whole mechanism for this, we don't know it all we need to talk we need to talk about the basic Basically there is a spring fitted here A very sensitive spring is fitted and this It is our pointer which gives us our readings. gives us this soft iron core The reason why everyone is taking soft iron you will get it okay now this is the basic and this There is a coil in the coil, from here there is a positive and from here there is a negative you are like this imagine it like this imagine it like this only one okay so now how is this going to work I will tell you the current pass from here we will talk about it, it will roam around This will produce a stretch in the spring The pointer will move around and the current reading will be will give means it is working on torque But before that watch a video where View the galvanometer from inside the case whether it actually resembles this Do you see it or not, come on this is a real one Galvanometer and this is from 12th class The galvanometer given in NCERT is What is inside our real galvanometer Everything happens the same way that we were taught Let's open it up and check it out So after opening the back covering this is what It looks like there are a lot of things out there right now We'll have to open this now, There are readings, you will have to make a chart of it Let me zoom in a little for you, this thing You can see this, we have this there is spring and with spring our this The pointer is connected, you can see how is this creating tension and The most interesting thing that The life of a galvanometer is its radial magnetic field now these two things you are looking at this and this its radial Magnets are for magnetic fields You can see that this is a magnet it has a shape stuck on it that's every 12th The child knows why this is done There will be turns of copper wire inside it as well I am busy trying to pass the current It revolves inside it so our studies Whatever has been done is absolutely correct so yes Ruffle, you must have understood it friend, it is obvious unless you work yourself beyond that If you don't make it, you won't understand any better You will get it but you must have got a rough idea that How does a galvanometer actually look now? Just understand how it works I have put a current pass inside it from here First let's understand its working Only then will you understand mathematically as well, now I am the reason behind everything and everything will come why soft iron is taken radial Why do magnetic fields lee a At this time, when a magnetic field is You are going to a particular point, aren't you? We call it the radial magnetic field Radial as in the radius of the circle Now if I pass some current from here So what is the first thing on this entire coil which there will be a talk on this because just read the current carrying loop kept in magnetic field If you experience some torque then you will feel the torque Now because of that torque this whole thing the coil will rotate Because of his wanderings there is such a The setup is mounted in a spring that costs Its rotation will create a a stretch will be produced in the spring due to torsion strain will arise, tension will arise and then such a mechanism is installed that its By rotating this pointer will move here or there If this spring rotates like this then suppose If you turn around like this, it will go here again This is a float, it is -1, understand it as anything, friend we will write the count later If we give the count, it is not even written down beforehand Let me explain everything and by rotating this pointer we will Obviously we will calculate its DI This is a very big topic, moving coil Galvanometers are available in two batches Classes run for two hours here one shot If yes then I will explain it to him in 15-20 minutes I would like you to pass the current from here torque was applied to this coil and it rotated in the spring The pull created by the pointer is here and there okay now some questions first we have asked here Why did you choose soft iron? The answer is next In this chapter you will read about soft iron being a very good magnetic substance the special thing is that that if you expose it once to a magnetic field and then apply the magnetic field If you remove it, it will also get de-magnetized The rest of the iron goes there cast iron pig iron wrought iron if you Once they are placed in a magnetic field If yes, then somewhere or to some extent this Achieves a permanent magnetization But brother this is soft iron temporary Achieve magnetization seconds what if i go straight here If the magnetic field produces torque then Do I know the formula for torque? The formula comes without theta and theta changes frequently due to which the torque It changes but in this case I want I want my torque to be constant go because I would like to whenever I If I pass a certain amount of current then my The pointer is in a certain amount only Give deflection so that the reading is same every time Only then will the galvanometer be useful for that I wanted to produce constant torque so some This had to be done so that theta becomes 90° Or if there is any angle which is fixed then We also took this soft iron core as And look at the magnetic field, what will happen if you take it like this what happened is it always had an angle with the surface made 90 and always made angle 90 then torque one of the theta ones in which the theta one If that part is removed then the torque It has become constant, brother, come and see Working understand like I did inside it If current is passed then a torque is produced on it This happened right, this torque on the coil was created And because of this torque there is a torsion here Strain was created, I would have called it a t-s hmm now the formula for torque is like this b by b sa theta and torsion strain of formula k theta is in 11th class I had read that the formula of force k was one and the formula for torque was k theta now sa theta Who This is a different angle brother, don't get confused The angle which is sa is different and theta here there is deflection then here If there is no confusion, I would take it as Alpha hmm let's go alpha okay what is this alpha How much deflection is the spring producing Because of that it has come to me here b a a theta so we made it 90 radial Magnetic Field If it becomes 91 then from here it becomes alpha What is the value of this b n ba k and aa I have has taken out Now what I am going to ask is very important The question is, brother, I have still got about two This must have been a one shot for more than an hour, right? I must have been going for about an hour by now I didn't ask you a single question so it's two hours long Went Not a single question will be asked in the comment section I want an answer to this if I A galvanometer You all have just got your In the video I saw a galvanometer if I If I make a galvanometer and pack it is this the bracketed part will it be a constant or a variable if I Make and pack a galvanometer so this is B A and K this is a galvanometer Will there be constants or variables for Answer this quickly in the comment section honestly is this B.A.A. and K If it is a constant or a variable then the answer will be is B A and k will be constant because B What is magnetic field? What is number? of turns what is a what is area and k Spring constant is a galvanometer will become constant for now if this All in one for a galvanometer If it becomes constant then I will give it a new I am speaking of constant which is ji here But you can understand that whatever is happening has happened Is B A Ba K which we call galvanometer It is also called constant which we It is also called galvanometer constant because For a galvanometer the constant is And what if g is a constant here? It can be said that the deflection It is being produced directly what is the proportional to whatever the current is Deflection is occurring here It is being produced directly is proportional to current and this is what we This is what we wanted brother that when we Pass current through it, it has a There is deflection and when we pass more current If this is done then there will be more deflection and less current will pass If it is done then there will be less deflection, I have done one Ampere Pass There was a deflection of 10 degrees So I got 1 ampere passed through 1 ampere I mean to say a micro because A galvanometer cannot measure one ampere Ampere current passed at 10 degrees Deflection happened, 2 amperes passed 20 I got three degrees and it turned 30 I passed 1 degree and this resulted in 10 degrees I wrote on the slip that I got one two passed I came here, wrote two, wrote three, like this and wrote it on the slip of paper, yes it is like that I did not write it but printed it and now all this It has been made in the standard way but it is fine I made one like this and I made a galvanometer Packed and sent to your home now you Go to your house when an x amount of If current is passed then that much Should get the deflection that I pack So if you feel deflection If it reached till here then it is obvious that the current It will be 1 ampere only and now you can use the galvanometer To measure the current with a galvanometer you can detect and measure which you have to do it you can do it the point is that here But your galvanometer is ready. In which what current did you pass and He is one on every current He is one on every current giving certain deflection which we I wanted it too, okay so it's ready Our galvanometer now has a sensitivity of What is a Galvanometer? Galvanometer What was the purpose of making the galvanometer The purpose was that we could transmit a small current If you can detect it, please tell me quickly If you have a galvanometer If you want to make a good galvanometer then you Do you want more money at least on current deflection is more than or more than There should be minimum deflection at high current Think about what you want, a good one Galvanometer What is the one which gives maximum power at minimum current Give deflection or maximum current But at least it is obvious that you want that there should be minimum current and maximum Deflection is good for these questions in exam Big come we have radial magnetic fee Why so that the torque becomes constant Write down why you took soft iron Bhaiya, it is fine in your own language, isn't it? come on the questions come on so what do you want Do you want me to have a galvanometer like this? which should be at least on current and maximum on Give deflection because it was made at least I went to detect low current what is the sensitivity of galvanometer It has two sensitivities, one is Current Sensitivity Current Sensitivity What is current sensitivity and deflection produced Deflection Produced Unit on Current deflection produced per unit current so if I say current sensitivity What is the current sensitivity? How much deflection did you produce The deflection you produced per unit current if you have increased the minimum current If the deflection is more than then the current You understand now that sensitivity is high, right? what is alpha by aa if you use this formula talk about what is alpha by ig Alpha is by IG and what is G which is B a ba ke kya hai ji whatever we have b a /k yes then instead of g I can write b a Ba k So if you want to make such a galvanometer Do you want one with higher current sensitivity? yes it means that it is at least on current and at most If you deflect too much then you will get a g The value has to be kept as high as possible and g How will the value of be maximum when b means the magnetic field will be greater than n That means number of turns will be more than a or That means the area will be more and k means Keep in mind that the spring constant will be less Practically if I increase b then The galvanometer will become bigger and heavier area If I increase ke it will become bigger and if I reduce ke If I give it to you, the spring will keep getting fragile and weak It will keep happening, his life will keep getting shorter Because of which, which is actually a way for us He is the only one left with us, who is he brother We have the option to increase your number of turns Because by increasing b and a the galvanometer Decreasing k will make it bigger and heavier the spring will become very brittle or His nature will change but the main point is that If you actually need practical current The only option is to increase sensitivity In Number of Turn Theory, someone asks you then increase b increase n increase a increase k decrease But practically the number of turns would be Along with current sensitivity we have another The thing we measure is voltage sensitivity Now why does voltage sensitivity come into play here? I'm giving you this right now Explain why voltage sensitivity because now we are going to read that How to convert galvanometer to ammeter and set the galvanometer to volts in because we measure the galvanometer in volts then you will get voltage Sensitivity should be known again Deflection Produced Deflection Produced But unit Voltage deflection produced per unit How much voltage deflection is generated Divided by voltage then voltage What is sensitivity? How much deflection occurred per unit Now how do we reduce the voltage deflection? Representing yet another from Alpha and What does the voltage you are using mean? alpha should I write aa in place of v Absolutely IF Voltage Sensitivity alpha is aa in up then what is the alpha/i Do you recognize me? Yes brother, I definitely recognize you. If alpha/aa is the current sensitivity then So can I change the voltage sensitivity to current I can write resistance in sensitivity upon am yes and do i have voltage sensitivity Also write the current sensitivity is g by r and I can also write g as b a ba k r i.e. current sensitivity and Voltage sensitivity is only 1/r There is a difference i.e. you can measure the voltage sensitivity There is another way you can increase it, that is Reducing the resistance to reduce the remaining current Sensitivity has nothing to do with resistance I don't have to give it's done okay it happened galvanometer now we're going to talk about how can we divide a galvanometer into ammeter and convert galvanometer to volt meter Will you all have a meter and volt meter Have you noticed that there are some differences between them? What is the difference between you all Know the difference between galvanometer and ammeter Everyone knows it, if you don't know then write it here hmm come on there are lot of differences between them kids here if we hurry let's do this this is I have an atter and this I have volt peas quickly between these Write down how many differences you find in Pause the video, I will also change the cell Lest the recording stops again soon So you tell me what are these Do you know the differences please comment section But write because I have asked you more questions today. If not asked in the comment section then comment Section P Write the differences between them As many as you can, we will move forward The one shot is about to end, hurry up ok i hope you have written it brother Basics of Ammeter and Voltmeter If we talk about the difference, then first of all you Everybody knows that this major does current and it measures The voltage seems to be series I think I'll know it in a moment Brother, what is the resistance of an ammeter because if it is to be put in series then it will be very should be low and because it is in parallel It seems so we want the current from above At least it will be the high of resistance Happen I need an ideal, that is, an ammeter of dreams There is a meter which appears in our dreams its resistance will be zero it is possible Not there. ammeter of dreams dream means it is possible No, but if we made such an A meter which would be the best meter in the world When will that happen when its resistance is zero Because now it is installed in ammeter series There must have been some resistance, so It will affect so its resistance will be low It should be zero, it cannot be less It should be like zero then it will be fun and one like that The resistance of the ideal voltage meter should be infa this is the difference, you should keep it in mind because this is According to the difference we use galvanometer A meter and galvanometer Now we will convert it into volts First let us discuss what a galvanometer is How to convert it to volt meter It is very simple Look, we have it With the meter and this galvanometer we have here But a shunt was put in, now what would this shunt be let me explain this is a galvanometer in which There will be a resistance of its own which is RG ok now the galvanometer The maximum current that can pass through is IG WE CONVERT GALVANOMETER TO ETER doing this means that we are doing a We are developing a device that measures low currents Now it can measure more current, it is simple We are building a device that will last for less Karan could have measured it, he could have measured more now if it is so so we want that now it is complete If income is measured then what have we done which is ours Galvanometer parallel with that we have another A resistance was installed which is called a shunt what is the shunt doing here if from here I want to measure income and If IG can be measured by galvanometer then the The remaining current will be the crux of junction law According to this it will become i minus IG is a shunt, that is, the one we call a shunt Joke is a resistance, what can be done here One is to put resistance in parallel This reduces your overall resistance you know the second thing from th class if I I want to measure ionization from here so I have used ammeter sent i through k but rest of the access current where did it go in the shunt because Which current can be passed through galvanometer IG is allowed because if you go over it then the galvanometer will get damaged because it It measures very small Karan and is very sensitive if it happens then what is the income here Range Of Current range of current means the current which we RG what do you want to measure maximum there is resistance Off Galvanometer resistance of galvanometer and what is IG Is Maximum Current Measured bye galvanometer okay now if it is like this So according to Crutch's law, here we are I want to find out the value of the shunt I thought that this is the maximum that I can measure from it If IG could measure the value of the shunt I have to calculate from here so crutch off According to logic, if I apply the junction law on y I apply it, oh sorry, I apply the loop law I will go, I am going clockwise so there is current we have aa minus ig into a and I will come down then will there be any gain from RG IG minus no it will go there ah mine eyes RG I will come and from here the value of A will come will go r g e upon me aa my i then you How much current can pass through a galvanometer You will know its resistance and you will know You have the range which you want to find out. Off current which you want the ammeter to measure you want me to assume that you want My ammeter measures 5 amperes maximum so this If you want to measure 50 then it is 50 According to this, the value of shunt is very will do it, that means this formula will change This is quite important, if you are one of these Brother, it doesn't mean anything, that's why You don't know anything in the exam if you are a convert galvanometer to volt meter You want to do it whose resistance is RG So you don't have to do anything in his series Why do we have to put a resistance in series? We have to make its resistance high If you want then just one resistance in the series If you want to apply it and do nothing then Convert the galvanometer into an ammeter It will obviously happen, it is on the slip The reading was in amperes, now it will be in volts Because again voltage if I pass current If I get it done then deflection is bound to happen Where 1 ampere is written on the first deflection What happened was now suppose you applied 5 volts and When he came upon a certain deflection, the slip But you have to write 5 volts, that is our aim The purpose is not that if I Galvanometer I want to convert it into volts then I Nothing to do, just one in his series we have to apply resistance which is here now But if you want, just for formality can you make an equation which is that Voltage is how much it will measure what is the formula for voltage irrfan-khan-whatsapp-status recording I faced a lot of difficulty because once I heard an audio it was closed, you might not have realized The bar lights went out, so okay, this would have worked it remains but after this one shot i hope you All your doubts must have been cleared, I will tell you again I will tell you if you want to answer questions then do it live go to section and other recorded I will keep answering its questions See you in the next one shot if this one shot Glad you got some help So please like this and comment Leave a nice comment in the section I know you will leave that next Bring the chapter quickly, but you leave that too but i feel that a little bit ah tell me this Let us know how you like our one shots So that I am more motivated with one shots For the rest of Shivdas's books here is the link You will find it in the description below See you in the next lecture, until then thank you so much thank you