Transcript for:
Electromagnetic Induction Overview

A very small, sweet chapter Is. Four to five marks in boards Questions arise regarding this. A little from Marx If I talk differently, this is very revolutionary. Chapter is Electromagnetism Branch Of. Revolutionary for what reason? Because The light that comes into our house, the electricity that Electricity comes, its foundation It holds chapters. first time someone The scientist put this before us. electricity to current without any battery Can be produced from. Hi Everyone, this is Ravana Rao. I welcome This wonderful Next Topper is for all of you. On the platform. Son Class 12th Chapter Number six electromagnetic induction. Let us understand this chapter. what will remain What is the flow of this chapter? So first of all a We will study a small topic called magnetic flux. Just like electric flux Same to same thing is going to happen magnetic of flux. And a nice CBSE 2024 I will answer the question asked. Very It was a nice and nice question. Then Faraday Sahib was the scientist who It was said for the first time that the current Can be produced without battery Is. So his experiments, although very All the experiments were three of us. The experiment in great detail which our Understand what is given in NCERT. Will go. Then two laws will read that one One will tell about the direction That current will tell about the magnitude of. Then motional emf, inductance, ac The generator will understand it like butter. To you You will understand how to follow the sequence. She has been here. Why this thing only after this? Is it being read? Everything will make sense. Ending Stay tuned son. Let's start From magnetic flux. It is a very small thing Sir. As there is electric flux that a How much of the surface is magnetic? Electric field lines passed? This It is called electric flux. same beans how many perpendicularly from a surface Magnetic field lines passed? This It is called magnetic flux. very small This is its definition. So We write, son, that this magnetic field There are lines. Took one or the other surface. This How much of the surface is perpendicular field The line is passing. which we called magnetic It has been named flux. mathematically Its formula is written with B dot A. If you remember B.A there then E.A dot The product, that is, this scalar physical There is quantity. Remember, son of a scaler physical quantity because the dot product Is. It will be defined in two ways. One if If theta is given then the dot product i.e. cos Theta will come. ba cos theta now theta per all There is dependency. If the angle between the two If zero, the value of cos0 will become one. ba Will be written. If the angle between the two between the area vector and the magnetic field B If the vector of is 90° then the value of cos 90 Zero. This will be over and done with. These theta It was a matter of form. If b is in vector form and the area vector is also given as a vector It is given in the form. at that time we use The vector form of this flux is given by The equivalent of which we can write is bx ax + by ay plus bz az dot product gives us I know how to solve it, son. remember this The unit will be written in terms of magnetic field. Tesla Area to Meter Square. So Tesla * Meter square, also written as Weber Can. A weber is an SI unit and is equal to to 10 raised to the power at Maxwell wrote Will go. Maxwell, you might see him sometime. This is not the Maxwell of cricket. These Maxwell is the CGS unit of this magnetic of flux. I have developed this dimensional formula. I have driven it and kept it. But once you Please verify this in the comments section. Is it right or wrong? Because dimensional We should know how to derive the formula. It was class 11th. Ok? a good Let me ask you a cute question. of CBSE 2024. Look carefully. Very Cute question. Not the lollipop one Is. Because as many questions as electric All those questions we asked of Flux It can be here. But a good new one Questions asked in CBSE 2024. New Pattern question. What is there here? that we have been told that there is a coil which The radius is 10 cm. A coil whose The radius is 10 cm. give a magnetic field 1 i cap + .5 j cap milli Tesla Found it. Keep in mind that milli is the unit. 10 Rays to the power of -3 will be written as Ok? true that outward unit vector normal to the surface Coil is this. What is this thing you have given me? Read carefully. unit vector normal to the Surface. The normal area vector to the surface is Is. The unit vector of that area vector is I have given it. 0.6I cap +.8.8j Cap. Magnitude of the area from here will get. Unit vector of area We will get the direction from here. So two It is a different matter. And we have been asked How much magnetic flux is linked with it will be. Did you understand the story? So first of all So write down what things you have given me. From. So in the given data I wrote that This much magnetic field has been given. of the area I can work out the magnitude because This is some coal we are talking about, right son? These Someone is talking about coil. So I did its The radius given was 10 cm. meter it 10 raised to the power -1 Squared and multiplied by pi If done, its area will be πr². and this Area is perpendicular to the area surface From. So the area vector unit cap was given. So 0.6 cap + 0.8.8j Cap. Now we have been asked, son, How linked will the magnetic flux be? How linked will the magnetic flux be? So We can write flux b is equal to a seen We used to write with a dot. Yes sir. b I don't know the value of this sir. Oh, I know, sir. I have given it. We can convert the area vector into area The area unit will be written in the form of cap. See how the value of b is written? Forest again This i cap plus 5 j cap into 10 Re to the power -3 then the value of this area is πr² So π * 10 to the power of -2 and the dot product After this we will write this new thing dot By producing, we will write something new which I have given 66 Cap +8j Now do some calculations with ii. So the forest The dot product of 6 and one is 6. Plus 5.8 So this will become four. I understood something In? This is five. Pay attention here to this It's five. Ok? So plus 0.5 j cap. So by .5 into These et. Ok? So this will happen.4 something came Got the point? Did you understand anything, son? Look carefully. Look carefully. It will be done by intuiting. These are 10 rays to the power-3 10 pi into 10 to the power -2. Now Simplify it now. Now this Simplify it. It's just a little calculation, son. calculation So you will have to do it yourself too. that's why I said a different question was asked. This different dot should not have been used directly. But Had to write the unit vector. use it after Was. Now you will solve it, you will simplify it. This will become a forest. This pie will come as it is. 10 The Rays will become a Power-5. value of pi You can also write. The value of pi is 3.14 Will go. And this will be written in Weber. If If I convert this to micro 31 31.4 Yes 31 this will come in micro. Weber would write something like this. So my thoughts The option that will be formed from this will be absolutely correct. It will be made. Look at the calculation carefully. I have written the value of pi as 3.14. Don't get confused. good question Was. That's why I told you son. its very Simple questions carrying one mark each Questions have been asked for two marks each. But he Will be made. Did you understand electric flux? If it is there, it will be made. One of the magnetic fluxes This new question was asked. be careful Look at this. It is quite clear cut First of all write Swaha in the comment box. The question is also a very powerful question. Ok? Now we will move towards something new. C The option is a perfect fit. Now for the new part Faraday's experiment used to say. But, isn't it? Its first Let me put the introduction. For the first time, someone like this A scientist came and told me that There is a current carrying wire which Because of this, magnetic field is obtained. I I I am laying the foundation for the experiment first. Some current carrying wire, Austrat Sahib said this It was observed that there was no current carrying There is wire. current is flowing in that wire Is. Because of that current we get magnetic The field was available. What sir? Electric We get magnetic field due to current. Was being. This is the first time someone told me that It was observed by Mr. Austrade. Was. Now here the mind works, Mr. Faraday. That brother, this can also happen. from the current Magnetic field is being detected. So why No, current is being generated from the magnetic field. It is possible Nature has a cemetery. So this The reverse process can also happen. These Mr. Austrade told and Mr. Faraday Its opposite is that brother, this should also happen I should have, right? This can also happen. So Faraday Sahib laid the foundation for this matter. I thought it should have happened like this. Magnetic Current produced by the field Needed Now that means a lot to me churning, churning, churning and experiment. Only Worrying is not just thinking. Let's experiment. So the three The experiment is very famous, it is It is given in NCERT. and that NC that We are going to understand the experiment through some animations. Have been. So let's get started. Here it is Experiment. So son, experiment number One Faraday sir. Took a coil. of coils with a galvanometer, voltmeter, a meter Whatever you want to say, actually I took a galvanometer. But here at The animation shows a volt meter and simultaneously We also jointed the bulb for a good feeling Is done. You can look carefully here Any external battery with coil Not there. Still this bulb will glow, this means Current will flow in it. How is this now Can it? Mr. Faraday made the same observation Did. First I tried a lot to place the magnet like this kept. placed in the reverse orientation but then The bulb did not light either. This means that here No current was flowing. Now In anger, he threw the magnet in such a way Threw. When he threw it, he observed that There's some deflection going on here. Also in galvanometer. And some more effects here But we still get to observe. You Watch carefully as the magnet goes in. Then the direction of the current was something else and when When it is coming out, the direction of the current is something And there is more. Moreover, if the polarity of the magnet Even if it is changed, the current here We get to see the opposite direction. So one thing he observed was that magnets By bringing it into relative motion, the current here You get the flow. lying at rest like this So nothing. look but have relative motion If it is there then current is flowing. why this Could it be happening? So he put a lot of thought into it I thought brother, if it is a magnet then it is magnetic. There will be field lines. and the magnetic field lines here inside Change is happening. This means number of fields The line is changing. Number of field lines Magnetic flux due to change The change must be happening through this coil. That Magnetic flux change through the coil And we are getting electric current. Which is also called induced current. These That was experiment number one. that the magnet By bringing it into relative motion, we may Even if you move the coil, the same thing happens. Observation is being received. move the coil Can. No, I can't do it in this one. But if there is any relative difference between the two If there is motion, the magnetic field lines change. Will happen. The magnetic field lines which change Magnetic flux change due to and we will get the induced current. These His first experiment and first observation Was. Now it is time for the second experiment. In the second experiment, he used magnets In its place a current carrying coil was placed on which The battery was joint. Now the first coil was It is coil. Bulb joint above Or suppose there is a galvanometer joint is made which causes deflection of current told about. We take the bulbs so that Understood it well. If the light blows The light in the mind will also be lit, hence the bulb Let's use it. Look what happened that we It is known that a current carrying loop It behaves like a magnet And to bring this magnet into relative motion Some current is being induced there. He found this in another experiment. Look at this second experiment. See. I am bringing it into relative motion. Am. The bulb is glowing there. What does it mean That current is being induced. why is it happening will be? Because sir, this coil That too produces magnetic field lines Still working. When brought closer, the magnetic Field lines will be growing. on taking away The magnetic field lines may be decreasing. in Change in short magnetic field lines Due to which there is an increase in magnetic flux Change is coming and in the magnetic flux Due to the change in current here It is being induced in the second coil. So For the first time in history, someone said that Change in magnetic field also current due to magnetic field Can be induced. what an amazing It was a matter, son. Today it is very terrible In the format we read and also use Are. But it's a big deal to think about it for the first time. it occurs. It's a big deal to think about something new for the first time. it occurs. Its experiment number three also Is. Let us understand. Here is the experiment Number three. In experiment number three He placed the coil between the two. Relative motion was not done. Just Coil As It is in which we need a battery joint somewhere It has happened. And the first coil as it is in which We have connected the galvanometer. The bulb was added in the animation here But there is a galvanometer. And now we both are There should not be any relative motion between the We are not getting it done but we are here to There is a switch which we can turn on and off. Have been. The switch we're flipping on and off Are. We first turned the switch on and then off. Did. Turned it on and turned it off. Turned it on and turned it off. So when we turn it on and off In that just interval, we have here Current current can be seen. here To be observed in a deflection galvanometer It is available. We get to observe this. Shortly after turning on, no No deflection. a little while after closing No deflection after that. means that he Just like turned on the deflection from shut. Shut down deflection. So on the same And in just the interval of closing we have here But some deflection of the needle in observation It is available. This means that just on Some magnetic field lines when closed Changes must be happening then only we should go Getting deflection. So this is the whole It was a complete experiment. All three of these three Experiment. My first experiment As mentioned earlier, magnets are relativistic When motion is done, we get a deflection show. Is. The second experiment was that magnet replace it with a current carrying coil relative to the one to which the battery is connected Even after getting the motion done, we have to go here We get a deflection and thirdly, we switch If this relative motion is not done then turn the switch on and off then also for that time interval smaller time For the interval we get the diff deflection Is. These were three experiments in total. How are you writing? in a very sweet way I have written it here. once you Read it carefully and understand it. whatever I have said it and explained it, it is the same. So Conclusion in short it turns out that any Magnetic flux will change in any way with Respect to time so we have induced current will get. We will get deflection. Ok? For example, if the magnetic field lines change It must be happening. If the area is changing or angle between magnetic field and area If the vector is changing then these short ba cos theta, either magnetic There may be a field change or an area change. It might be happening or the angle between the two might change. If it is happening then we will get some deflection will get. This is the conclusion at the end. Only then did Farades Sahib give his law that Change in magnetic flux produces a induced emf and that induced emf = di / dt with respect to time which changes It will be effective for induced EMF Will remain. This is a very sweet formula and The numericals that come in this, son Very cute in the boards Lovely ones. Now we practice I am going to do it son, it will be a lot of fun. di/dt Why is it written mode? I will explain further now. Now Induced current. Now check if the coil is full. As we just read, one in five The galvanometer was joint. If the coil is full If it is complete then some current will also flow in it. Now we already know how much current It happens? then current is equal to induced EMF Divide by R. Whatever this coil has That will be the resistance and this will be the induced current It will be written accordingly, son. Ok? Induced current divided by resistance. If you want, you can also write charge induced. Also write how much charge would have been induced. You can. You know, we write with IDT. Put the value of charge I. EMF induced divide / r into by dt attention Take a look from it. Induced EMF Induced Instead of emf, I write di / dt d / dt this 1 / r and this dt dt dt will be cut Integration di / r then you get Delta F / r What have you got, son? have found The value of the induced current and the one below The value of induced charge is found to be The first thing I understood was the main thing What is change in magnetic flux? Produces an EMF which we have induced It is named EMF. If the coil is complete The coil is complete and both ends are closed. Current will also flow here. If there is no Then the current will not flow. So induced I will talk only till EMF. Still the emf is will get. Yes, potential difference only will get. The current will not flow. current flow The coil must be closed to do this Is. It is necessary to have a coil. So induced EMF divided by r is the induced EMF d / dt 1 / r If we talk about the charge i ddt The value of i is given by induced emf /r We put the sir value on top of Simplify did dt dt cancel out di / r d ka By integrating we get delta phi So change in flux divided by resistance That is equal to induced charge you get a The good thing will be seen that this time This is the thing that does not depend on The flux which is the charge induced is He does not depend on time. It doesn't depend. A good thing is meditation I have found you. Whose whole incident was this? It belonged to Mr. Faraday. Ok? We have yet to The direction of the current is not known. That Lange Mr. La Lange will tell you. Now we first Questions on Faraday's Law What kind of questions can be asked? So First question asked in AIPMT 2012 The question is gone. Such questions are our In CBSE boards or whatever respect There is a state board, questions can be asked there. What kind of question is that coil of a resistance 400 Ohm is placed in a magnetic field. Magnetic flux is given. Yes, we give it Given that the flux 5 = 50t² + 4 in the current coil at t = 2 sec. We have to remove How much current will flow at t = 2 seconds. So first of all it is necessary that you di /dt do it. By differentiating it, you Removed induced EMF. So we Removed induced EMF. 50 t² t² then Two will come forward. 100t plus will come here Do four. The differentiation of four is Zero. Differentiation is necessary, son. So I slept We have got induced EMF. Now we If we divide with resistance then we will meet The induced current will go. induced Current divided by R. Induced current means 100 T / will come to 400. So this will be available T / 4. If we get this, we got it in ampere. At what time did you ask? is at t = 2 seconds I have asked. So at t = 2 seconds we can write If it is 2/4 then the answer will be 1/2 ampere Which will become 0.5 ampere. What did you understand In? Son, the calculations should be a little faster. Can. But this is useful. Keep understanding. Keep moving forward and solve along with me Keep doing it. This is the biggest thing. Otherwise it will seem as if the head himself We keep doing it. We are being left behind Or I don't understand something. Also when you feel that the speed is too much Pause and then proceed. to solve by yourself Try it then you will get the idea that Yes, I understand this as well. Ok? One And ask more questions. Look at the question What have you given that 800 tons of coil of a Effective area. Meaning, give the area of ​​one coil It is kept. Tell me what is the number of turns It is kept. Kept a perpendicular to a magnetic field when magnetic field Equal to 5 * 10 to the power -5 Tesla. Who I have given you things, write them down well first Yes, we have to understand. Ok? When the Plane of the coil is rotating by a 90° around the any of its coplanar axes in a point one Seconds. Meaning at point one second this coil Rotation is being done. that the first case I suppose Coil was like that. coil assy This area was a vector and also a magnetic field. It was in this direction. and in another story We are rotating it like this. This area The vector will become perpendicular. and this The magnetic field is in its direction. So we're rotating this with in a Point one second. Then we were asked this How much induced EMF will occur? Firstly Will he come or not? I will come sir. because we Changing its orientation. So somewhere Neither magnetic field lines nor magnetic There must have been a flux change due to which we Induced a vape will be found. So whatever you give I have kept it, write it down properly first, son. So Look, the number of turns is given, give the area has been placed, magnetic field has been provided and Tell me from where to where you are doing orientation. It is kept. Ok? Tell me in how much time It is kept. So first of all, the things that were given You can remove the magnetic by using it. What will be the flux? So the magnetic flux We used to write the formula as B.A BA cos theta. But also give the number of turns in this story. Have kept it. So ba cos theta for one turn It happens. So the total flux will be written as nab cos theta. Yes, nba cos theta or nab cos Theta, both things are the same. Now Induced If you want to find out the EMF then it is a simple matter di / dt But in this story there is a difference It's not a matter, sir. This is a big change. Big There is change. That's why we can write nab cos theta theta = 0 nab cos theta theta = 90° In how much time? Delta t time = 1 second In we simplified it. cos of 90 The value we have is zero. thats Why will this become a complete part? Zero. nab cos0 / delta t cos zero key Value One. The value of N is given. of a The value has been given. The value of b is given. The value of delta T is given. Bus You have to substitute and find the answer. Are you understanding things? Good to see this There was a question and in our examination such Questions are coming son. believe me you If you look at them, they are questions and they Questions here like this somewhere examination Are being made from. So don't ignore them Can. It is impossible to understand that our It is not for examination. From here he Questions are also coming in our examinations. Are. Similar questions are being raised. So The correct answer will be 0.02 volts. Option C will be correct. If your calculations are correct If so, write it in the comment section. Yes Sir, my calculation was correct. another question We do. Meaning you have to master it. To myself. Magnetic Flux with Respect To time change hone pe hume induced EMF is obtained. How to find its value She goes? I have to master that. understand What is given here? first time someone We have received a question about graphs. The coil whose resistance is given is 10 ohms. Induced current developed by a changing Magnetic flux through it. Shone in this Figure. OK sir. I mean, somewhere I A graph of T is given and we are asked to It has been asked what is the magnitude of this change In Flux Through the Coil in a Weber. Us Change in flux has to be removed. straight this time Change in flux has to be removed. Ok. Now attention Two sons. You know something that So that the flux can be removed. Directly then No, but there is a connection between two things here. But. What is the connection that IDT is giving us? Is. IDT and one thing to remember is that the charge which It used to be i.dt only, it used to be integration In. so area of ​​this idt it will give you a Value of charge. And we know one thing Sir. Just before you got it done that Charge is equal to Delta 5 / Delta T No sir, I did not have time. Divide by There was resistance. This is the only factor It was something that was not dependent on time. These Check out the things mentioned here. This special I told you after talking to you, look at this Delta phi/r is not dependent at all On time. This is what we got as induced charge An equation for. When Mr. Faraday's law We were reading about. a little bit I had done the calculations and later this thing We came to know. Did you remember anything? Remember? So we'll just use the base of that and Will find the answer. So I took out the area. On calculating the area, we find that 22 We have received the coolant charge and need to remove it. Delta phi by r equal to charge used to be So we figured out delta phi is equal to to charge * resistance to this to into If the resistance is given 10 then it will become 2 Weber Two Weber will become its answer then option number B. What calculations will become absolutely accurate? Sir, I understand something new. A little bit of new thing. Is. But if we look at our There is such analogy to the previous chapters. But it has also been used. So if the story is about your Even in questions, in these questions It will be done easily. And the opposite can also happen If you do not read that chapter carefully You can also do the calculations of this chapter well. If you understand then slowly slowly slowly The level of calculation will increase. The thing is coming To understand? Now a question for you son. I got four-five questions asked. now one Question for you that a big circular coil I have given it. This is a question from NEET 2022. Correct Is? Give the circular coil number of turns Are. Its average radius is given as 10 meter. rotating about its horizontal Diameter 2 radians per second has a vertical Component of a Earth's magnetic field is Dec. Ok? The electric resistance of this Coil is so. then maximum induced We have to remove the current. We have to remove Maximum induced current. This question's You will tell me the answer in the comment section. There is something new here. But this new thing can also be understood. Yes. tell you In the comment section. Did you manage to count or not? Have you been able to count? This was the first thing about Faraday's Law. of. Now we are moving on to another story. Which is the lens law. Son, this question has been asked So don't worry if you don't make it to the bat. Because we come back to this question. Solve using generator concept also Are going to do it. Now going to read Lange Law. Lenz's Law about its direction will tell whether induced current or induced In which direction will the emf be? understanding is very I will explain it in a very nice way. These Political political happening in the opposition It is like a particle. of the political party The kind that always opposes change. opposes. I am not saying this. Lenze Sahib was saying that induced The current will be in the direction of Oppose this change in direction Can go. For example, if this magnetic field Inside, she's growing a lot. Magnetic field increases with time Still working. So first identify the change do it. What is change? Mr. Lenzi asked First of all, what is the change? Sir Magnetic Field Is there that change in the internal direction? No. The magnetic field is increasing. These There is change. It is increasing. That is change. Then this To reduce change or oppose change. Change To oppose. About opposing change In Lange Sahib told that the induced The current will be to oppose this change. It will be in direction. So here is the change Grow. So the magnetic field must decrease It will be according to you. If magnetic If we want to reduce the field then we have to If the magnetic field is in the direction To reduce it, we need to take the outward direction. must produce a magnetic field that the induced magnetic field is It will be in the outward direction. inside The magnetic field is increasing in the direction. So Lens sir is saying that it is induced The magnetic field due to the current will be It will be in the outward direction. Then go here Will decrease. This will happen some. It is still growing We have to reduce this. Will decrease. So to decrease In which direction is the induced current will be? Hmm sir ji. thumb out In direction. Curled his hand. to the hand This is the induced current when curled. I am getting directions. look carefully Take it. This is the direction of the induced current. I am getting it. This is the induced current of I am getting directions. I understood something In? This gives the direction of the induced current. Has been. Did you understand? See lots of it I will give an example. You have a clear cut Will go. But first, identify the change. What is the change? Opposite of that change Do it. Like the magnetic field here. Let's assume it's on the inside and It is decreasing with time. So what changes? Is? First of all, identify the change. Change inward direction magnetic Field is what it is. No sir, the change is that The magnetic field is decreasing. This decrease Has been. So Lange Sahib is saying that Sir Oppose whatever change is happening if it decreases If it is there then increase it. If he is growing So subtract that. So this is happening here. In which direction is it? This is the inside It is in direction and is decreasing sir. So Induced key direction enhancer Will come in direction. in the same direction Will come. Will be of supporting nature. who is dying try to keep it alive and He's moving too far ahead to stop him. Try. This is what happens in the world. So see, the direction of the induced current will be It will be under his direction. This will be in the direction of the magnetic field That it will support it. Will support this. So the magnetic field in the inward direction Will happen. Magnetic in the inside direction field and to support this Begin Shum. Ok? This is the current Direction. This is the induced current of Direction. This is the induced current of Direction. Look carefully. This is the direction of the induced current. What Did you understand, son? what happened To understand? Understand carefully. Think about whether you Did you understand this incident? No tension. We are its I will give many examples. So you have this Things slowly slowly become clear cut Will go. But first try to understand the matter. What you have to do is first identify the change. Then you have to hold this change and oppose it. If If it is decreasing then try to increase it. If If it is increasing then try to reduce it. perfect. This is what Lange Sahib had said. The polarity of an induced EMF is true that It tends to produce a current in which Opposite the change in magnetic flux. That There will be a change in direction to oppose it. The current will flow in the direction of. and this Lenz's law is based on conservation of energy. This question can be asked in MCQ. And you can also ask for proof of this. Can. Just a small two marks A question will arise about which we will also Will discuss. perfect. Even the thing. Let's ask one or two more questions. Look at our Go to NCERT. One, if I asked a question I asked if there is a magnetic field. These Magnetic field is something like this. Tell me in this What will be the direction of the induced current? Hey, how is that possible sir? First tell me the changes. Change There is nothing, brother. Magnetic here The field is constant. is constant. Finished sir. So here the induced current You won't get it. Change is necessary. Change is necessary. In this story you You will not get any induced current. Yes, Somehow if this coil is small or big If it had happened, the area would have changed. Then magnetic Flux could have gotten you. to the same story Let me ask you, let's say there's a magnetic field. He is that constant. but slowly Its area is gradually increasing. Its The area is expanding. Such as Like son, this area is expanding. Look, this area is expanding. So this story Tell me which is the induced emf Will it be in direction? This increases its area Used to be. be careful. The area is increasing, meaning that the magnetic field lines inside the head increase May have been. What is change? First change Identify it. Sir, increase the area here. Used to be. If the area is expanding then go inside magnetic field lines are now more Will happen. First, look, this line is not going away. Was. This magnetic field line does not go Was being. Now the inside area has increased. Area increased So the number of field lines increased. because of which Flux phi has also increased. Flux fi also increased Is. So due to increase in flux, the inner The magnetic field has also increased. said so Will go. So induced will say that this Reduction is necessary. Magnetic inside Induced to reduce the field The magnetic field will be outward It will be in direction. and outward direction If it is in the outward direction, keep your thumb In. curl and you will get some direction will get that This will happen anticlockwise. anticlockwise Will happen. Did you understand the point? which is here You will get the induced current will be found anticlockwise. Are you getting the point? Hey son, have you come? Got the point? It means that first change Identify the . Whatever change is taking place Trying to oppose that change We have to make the induced current flow. These See NCERT example. Oho, A brilliant question not from NCERT Has come. I will give this as homework. To you In this story I have to tell that the induced current for this coil What will be the direction? a current carrying wire which is in the downward direction and the current The value of is increasing and the value of current It is increasing. The current due to which magnetic In which direction will the field come first? Curl it in a downward direction. Magnetic here in the outward direction There will be a field. And if the value of current increases If it is increasing then the magnetic field is also increasing Will happen. Now you can tell me the rest of the story in the comments. This should be explained in the section. Magnetic here Field lines will also be growing. Now its You have to tell me your answer in the comment section. The current in this coil will be clockwise. or anticlockwise. is coming Did you understand? another question Of NCERT. Example number one. Look be careful. What is happening here? now now Let's do it quickly, yes, be careful to see this. The first one is the loop that's coming in. Inside If it is coming then the area is increasing. Area Increase If the number of field lines is increasing then the number of field lines is increasing The one inside. If it is increasing then decrease it Will be necessary. outward to subtract Magnetic field will be available. here The induced magnetic field is that outward It will be in direction. outward direction I placed my thumb. This anticlockwise current It will flow. in this story in this loop The current will flow anticlockwise. did you come Did you understand anything? The other one opposite this Is. In the second one, we're pulling out No. If you pull it out, the area decreases. Used to be. The area is decreasing. effective area Whatever is in the magnetic field is decreasing. If the area is decreasing then the number of fields The lines may also be decreasing. It is decreasing. So we I will try to support it. This We will make the current flow in the direction. So To make the current flow, the thumb is used for the same In direction and curled. did it yesterday The direction of the current has been found to be something like this. Current We have found the direction to be clockwise. Ok? Same D as in the third story Something similar was happening in me. But like If you are taking it out then the effective area It is decreasing in this. It is in the B one. The effective area is decreasing. If it is decreasing then We have to support it. to support Thumb for Magnetic Field Key In direction. Did it yesterday. These clockwise The current is flowing in the direction. These Current flowing in clockwise direction Is. Look, they're taking it downstairs. Are. Effective if you are taking it outside The area will be reduced. Because of this. what's up To understand? Any things to worry about? No. One Bar bas leng loss set ho gaya dimna me. Then the story is clear cut. Another one like this There is a question. Come on son, let's ask one more question. Are. So the question we have is, There is a metallic ring which is placed horizontally like this It has happened. This metallic ring is kept. Its A magnet has been passed from above. Meaning This is how it is being dropped. then acceleration What will happen to the magnets? will be less than g. from g I have to tell you if it will be more. If the magnet As it is, you could have got it passed. No ring whatsoever If it had happened, acceleration due to gravity would have lost. But in this case something will happen the other way around. It is possible It may be more than ji or less than ja. Actually, according to Lenz's law, this incident Son, as soon as the magnet passes below If it does so, then because of the North, it will be like the North Pole. magnetic field lines emanating from She will pass more of this loop than she would. If it is too close then try to oppose it. Will do. Magnetic field, see below The lines are growing. The magnetic field is increasing Is. Downward direction magnetic The field is growing. So according to Lenz's law An induced magnetic field will occur which It will try to reduce the above It will be in direction. Only then will this happen. Now curl in its direction. touch it We are finding out that a current production Which will be known as current induced current It is known and it also tells something like this It will be seen that it behaves somewhat like the North Pole. Does. Look, now there is a ring like the North Pole. She is behaving. So when the magnet is near When it is done, it feels repulsive. from this loop. Then because of this its Acceleration due to gravity decreases Is. Less than g happens. you understand the matter I came to see the North-North repulsion here But the behavior will become like that of North. Although the view is from above You are looking from below. Because of this The direction of the current is determined. But You can tell directly from Lenz's law. That sir opposes the change. if these What would happen if the magnet reached the bottom? Even when it reaches the bottom, it is still a loop. According to Lange's law, it opposes change. That means he is going down then he has to come back Tries to attract her towards himself. That In this case also the answer would be less than g. When the magnet is near, it is passing right now It was then and even after passing Acceleration due to gravity g. means then There is a loop, it will pull towards itself. The loop is now He is opposing that brother, don't come. So much Don't come early. Don't come so early. gradually Pass from. So in short these opposites are going to happen The story will be based on Lange's law. Now we have said it many times before. That is why Lenz's law is based on energy Conservation. Now let us understand from this example That actually it is about energy conservation How it depends. Ok? I understand. Look, understand carefully. If we use Lenz's law According to this, it was told earlier that the lower Magnetic field lines are increasing. Below The magnetic field direction was formed. Induced magnetic field above Curled fingers in direction. Found the direction of the current. This is due to Lange's law We calculated it accordingly. Yes sir. Lenz's Law Calculated accordingly. Now, as if for a while Because in the opposite direction of Lenz's law The current is flowing. Opposite of Lange's Law The current is flowing in the direction. As That first there was this North Pole which we call a magnet Are taking you to. So, according to current Lenz law According to this, it will flow in such a way that here North Poles were made. We considered its opposite. Suppose we It is believed to be the opposite. Ok? Imagination Do it, imagine it. We do not want to discuss or think. So we assumed for the first time that this was current. flowing in the opposite direction Is. Ok? What we got from Lange's law Direction is being received opposite to that The current is flowing in the direction. These We have accepted it. Assuming the opposite from the actual Are. Let's see what happens. to be What is it sir? This is in the opposite direction Current. So it behaves like the South Pole. Used to be. Look carefully. It's like the South Pole He is behaving. It's like the South Pole He is behaving. Ok sir. If this becomes the South Pole, we It was found that it was between North and South So there will be attraction. Meaning that you are Pushing the pole forward a little And this was an attraction towards the South. Due to which this little shock will also happen It will take it to infinite distances. He will take you near at a very high speed. These What happened brother? a little bit lighter Pushed the magnet and it reached great speed From this magnet went to this coil. Why? Because you behave like the South Pole Had been. We thought of this as the opposite and then this The incident happens. as if the current is being supplied But it is not available according to Lenz's law. or the things that are found according to Lenz's law There is current in the opposite direction So it will behave like the South Pole. This North and a little bit of attraction in the middle of the South It also pushes the North Pole very fast. Will take you towards the South Pole. Brother, so much I did not give any energy. so even then This time the magnet has so much energy Where did she come from that she could quickly move around this loop It's going like this. This means it's very strange It is clear that you have no big work to do. If you want to do something, just apply a pinch and the work will be done. Such a story happened. this is so real This is contrary to reality, son. So read it It is written here that suppose that the The induced current was in the opposite direction to the one of Deficit means that according to Lange's law It is in the opposite direction from where it meets. Ok? Bar magnets will then attract Towards the coil and ever increase its Acceleration. Acceleration also increases every time doing. Meaning velocity then speed Look, moving at a very terrible speed May have been. We are also increasing acceleration. So this means that a small push Gentle Push On A Magnet Will Initiate The Process. A small push is what this process needs. will start the . and then velocity and Kinetic energy will continuously increase Without expending any energy. means his Then I gave a small push. after this So we did not do any work. still Energy is increasing, increasing, increasing is going, the kinetic energy must be like this I can't, brother. This is energy conservation Violet. So what we oppose I was reading a story about supposing and opposing That story about the opposite of Lange's Law is wrong. What Lange Sahib has said is correct. Induced current and induced emf are always The opposite direction of the change that is taking place Will be produced in. Joe Lange's Law Explained Therefore we will write that Sir, yes, whatever Lenz's Law explains its impact on energy conservation. It is based. So give me this complete question. Can be asked in marks. good at this Write beautifully son. These The question has been asked many times and Can also go. It is a theoretical question. But you must be able to argue. Son. Perfect even to the point. now one Let's move on to the second chapter. So far we have What have you learnt? Let me tell you. See Understand carefully. So far we have learned Is. The story so far has been saying that Magnetic flux yb = ba cos theta. ba cos theta. Ok? This is what we have read so far. either by changing the angle between the two or By changing the area or magnetic field change By doing this we can set any one of these three parameters Will there be a change or will two of the three also become one? Can be together. These parameters are changed We get an induced emf. That We can write the induced emf as di / dt This is equal to induced emf. Actually, there is a minus sign in front of it. It is written because according to the lens law This happens in the opposite direction. Ok? So this is the value of induced emf She has come. And what do we call this incident? electromagnetic induction. Induced Key The thing is electromagnetic induction. So Either the field is changing or the area is changing. Is it happening or is theta changing? So In majorly cases we have field changers. I have read the example. Now if the area changes What will happen? There is a road which continuously is moving back and forth due to which the area change is taking place and we get induced emf will get. And after this theta change will happen Things like AC generator. Theta Change It means the concept of AC generator will come. make take. Ok? Right now we are in the area about the thing that's about to change Moving forward, there is a road which The road is being moved forward. Look at this See the entire structure. a railway There is a track. What is it son? There is a railway track. This is a road on the railway track. We can take the road forward at V velocity Have been. And the magnetic field here inside Is under the direction of. Do you think this You will understand that gradually, gradually, The area will change. Area will change meaning Look, earlier the area up to this point was this In the magnetic field. Now the road as soon as The area moved forward increased. What increased? The area increased. So first of all, I If I write the flux then flux B = BA cos theta There is a formula. Magnetic here Both the field and area vectors are inside Let's accept it as direction. So ba cos theta ba cos 0 so this would be written as b * a. Ok? and the magnetic field as it is I can write the area as Okay. And look carefully. area l into tax value Take this distance completely Very happening, he writes. I see I'm going to write the change. Yes. I see a I will write down the changes once. Delta phi or d5 Delta Phi or d5 is written as db I More talk about direct magnitude I'm looking at it, take a good look at x or dx The further he has progressed in life, dx As far as I've progressed, I'll write straight away. that the magnetic field b into which area He's doing da area very very That area is so very different sir. length l and this dx distance and this dx Distance. So can I write this magnetic Field B dot l into by dx is correct. See There is nothing because of the magnetic field. But due to change in area, flux There has been a change in me. Now use di / dt Do it. di / dt di / dt dx / dt v Taking it with velocity. so the same So is its velocity. then di / dt Induced EMF you got it. B its Velocity will be written as V. So BVL is a A formula is being developed which is very useful. And this derivation is also very useful. Here you get the induced EMF We call this motional emf. what do you say Yes son? Motional EMF. So a complete This will behave like a complete circuit. In which this resistance is R. in which this The resistance is R and this railway means this is the conducting frame. The conducting frame is and above this frame like this This is how we are getting this induced EMF Us. That induced emf is equal to BVL. Now if you want to write it down, we You can also write the value of current. That Current I is equal to I induced is equal to e Induced Divide by R So We Can Write BVL / R BVL Divide by R I understand what son Derivation is very useful. Cute Derivation Is. This is a very cute derivation. what happened Do you understand? Perfect, any event, any meaning Is there anything to worry about, take a look at it Once properly son, that means 10 seconds each. Let's pause and see the derivation. Understand how to drive it This is called motional emf. Yes, confusion You may find that here What is the direction for the positive terminal? How will you decide? how did you draw Given that it will come in the upward direction only. How did you draw it like this? So for this one There is a trick. What's the trick to velocity? Place your fingers in the direction and magnetic Curl in the direction of the field. B v Cross B. v Cross B. Velocity Key Fingers in the direction of B Curl in. Thumb positive for you Will give directions to the terminal. What son? Thumb points towards the positive terminal Will give. Ok? Here are the things about direction. Here are some things about direction. One Also according to Fleming's right hand rule can be removed and secondly we right hand You can also calculate it using thumb rule. Because in actuality its formula It is possible, this is possible. BVL is defined as Will be written. We just wrote a simple that sir BVL that is the formula of induced EMF. But this induced emf The vector form is like this. VB dot l v Cross B dot l v in the direction of B Curl your fingers. thumbs up to you Will give the direction of the positive terminal. Attention So look, in this first one we did V. Placed fingers in the direction. Magnetic The field is in the inside direction. See Cross Magnetic Field Inside Direction I curled my thumb up. So that means that we need to know the direction of the positive terminal Found it upstairs. understand we The one who was moving this road, the road to We can treat it as a battery that has some emf B as much as VL. BVL The amount of EMF you can treat it like Are. Whatever internal resistance he has If it happens then show that also along with it. It's great sir. So if a road moves like this If we are in a magnetic field then we can Right, its induced emf = bvl remember Keep them very small and very cute Questions are asked from here son. Are asked. Many times, doesn't it mean you To rotate like this. Don't keep your ears stuck like this To catch, to catch, that length is something Such strange you will give strange that here A is a point, then some curvilinear ones like this and this B and v are moving with velocity. So how will you write bvl in that story or l If I write it, will it actually come? Do you want to take the full length or the one from A to B? I have to take points. You have to take direct distance. So In that story you have to take L effective that Join point A with point B Joined it with point B. Joe Dies Also got effective length, same effective length Have to use it in the formula. Direction of B Thumb curled in the upward direction In. V crossed B thumbs up In direction. You got this BVL Effective. Look at a good question This is a lovely question. Ask such questions Can. That's what I want to tell you Am. This is the question of 2014 that thin semi There is circular conducting wire. After seeing you BVL questions are very easy. The value of b will be given as You have told me the velocity, you must have told me the length. So Such questions will definitely arise. but but To tease you, he does some such strange things. Will bring the shaped wire into motion. So what will be? We know sir that it is effective I have to take it in this case. Ok? So let's read See, this is a semi-circular PQR shape. There is a wire that is falling. is falling Meaning it is coming down. It's coming down to something Let's say V is the velocity. So brother, we Why first take this big wire. Us I know that I have to treat it with L effective. So this will become L effective. From P to R these The entire part will become L effective. L effective equal to we can also write How much will it be, sir? Sir this R and this R so this will become 2R. Hmm and in which direction? Is it moving? in the downward direction He is moving. Ok? So this V below it Under the direction of. OK sir. wire down Coming in direction. Okay. The Potential Developed Across the Ring When It's Speed ​​Is V. We have to tell that its When the speed becomes V, then the potential How much will the difference be? potential difference In between the two means induced imap How much will it be? Oh, what's there to worry about? Is. The formula that was just written goes back Please apply. Induced emf = bv l And instead of l, l will come into effect. 2R How Came? This is so much distance and this is so much The distance r r will become 2r. So bv and length It will become 2r. So look at the 2r option carefully. From. Is there anyone here? It will not be zero. Something induced will come. This will also not happen. Not even the (pi)r one will be. 2rb Only this option will come. and r higher How did you know about the potential? Lower one in the direction of velocity Fingers, Direction of Magnetic Field I did it yesterday. Let your thumb give you direction Whose will he give? of the positive terminal. Big ones of the terminal. So this will be at a higher potential. Point with R. Did you understand son? Is there anything to worry about here? clear There is a cut. You can move ahead son. be careful Just look. Write it down once. Then Let's move ahead. Look at the road, we are one velocity in front and behind the magnetic field Were moving. What happens when these roads are roads rotated through a magnetic field Should I go? One end remains the same, the other end remains like this It is rotating. What will happen then brother? Till now we were doing the same road like this were moving or were moving like this or Were moving down. Now we take this road rotate in a magnetic field then what Will the incident happen? So it will be called rotational emf. If the emf is found then it is called rotational emf This motional emf is its younger brother rotational EMF so look carefully that if any road This road is being moved and rotated. whose length is l or radius is r Take it and let it rotate magnetically in the field, so the first thing is what in this Motional EMF will be obtained as Induced EMF Yes, you will get it and why will you get it? The reason behind this is also stated here. Actually it is doing this motion, so this road Stay inside the conducting road Magnetic field over the free electron A force will be applied due to the field. A force will be applied due to the magnetic field And all the electrons will go to one side. Due to which it is back to the other side and positive The terminal will be developed. Electric Field will come back and the electric field and The magnetic field does some work here Induced emf will be obtained. How to get it? Let's discuss that. Ok? be careful Look That whenever we had a big talk at x distance When it comes, we take the small element. So Small element for big thing this dx width of which is at a distance x and dx width dx For these elements of width, we write speed. Have been. So velocity v = omega * x It can be written in the form. Yes. x Distance is rotating away from and omega So omega * x now a little bit of the road Yes, believe this. It is just a road that Omega * x velocity upward direction I am running away. So this small part for d induced d induced equal to bv small element That means I can write dx further. of b The value omega * x and it will come out to dx. it A small induced EMF has occurred. Small Induced EMF has occurred. So bomegx dot dx. Look carefully. If I If I integrate both sides then this You will get the full induced EMF. that is equal to b Integration of omega x * dx x dx b omega sir integration done x² / 2 where where is the integration length So the total length from zero to zero is l. integration from zero to l and this gives us will get 1/2 b omegl² so if someone The rotating rod whose length is l is omega Velocity it is rotating then you can write Its induced emf = 1/2 b omega l² aa Are you understanding this, son? So For a rotating rod, we obtain the induced emf. will write 1/2 b omega l² 1/2 b omega l² rest of it will be called Rotational EMF and why it is obtained We wrote the story behind it in words above. Write it down once properly Based questions are asked. derivation Two is actually derivation number two Is. Numericals are asked from here. Straight formula based 1/2b omegl² now I will show you many in NCERT also. Numericals will be found but once Understand the proof of this, how it was proved Will go. Now friend, one thing is that if the rotating road b 1/2 b omega² is a rod having such a motion doing bvl rotating 1/2 b omegl² if such What happens if several roads converge? Will you go? First got a road moved. Then the same road Got it rotated like this. Now there are many such What if the roads come together? we are Will you keep writing about everyone, sir? we are 1/2b omegl² and to extract the direction What to do? In the direction of velocity Will keep fingers crossed. curl in the direction of b do. The thumb will give us directions. Just simple. So many such roads come together What will happen if he goes, son? So look at Omega It is being rotated with velocity. Ok? There are many 1 2 3 4 5 6 7 8 Eight is eight here also. maybe eight There may be more also. But The diagram is drawn approximately. Now Understand carefully. What's the matter here? See Take any one road. This catch I took it. So v * v cross b thumb this In direction, this is the positive terminal will form. and any one to the positive terminal For this the induced emf will be written as 1/ 2B omega square any means this ones for this one for this one for this 1/2 Omega for everyone Square will be written. Hmm, that's also true Is. Now look carefully, for each road I've done 1/2b omegl². and each one The road has a common point and another point is that of this surface of this conducting frame There is a point above which means if I If I say A for a moment, then this is B point. Is. Which B point will be common for everyone. Because there is no resistance in between. Is. Everyone's B point will become common. Then A and B point is common to all, it means it is a parallel Connection. This is the parallel connection of emf. It will be an example. EMF Parallel connection of emf Parallel Connection of Shells EMF means we can write cells, right? Can be written in the form of small batteries Are. So, parallel connection of cells Induced EMF as per calculation. Look, the first one of E1 / R1 + E2 / R2. This was the formula, right? Then E3 / R3. Now everything is equal here. It is there. Everything is equal here. Any If we write one, how much does it come out to? 1/2 omegle² everyone's length is the same, everyone's Omega beans and everyone's b beans. Yes? every For someone b bean. So e / r + e / r + e / r plus ding ding ding ding ding in the denominator 1 / r + 1 / r + 1 / r plus ding ding ding simplify Will you do at the last moment the induced EMF You will get whatever one gets. If it is written then 1/2 b omegl² its right The answer will come. No matter how many roads you take, brother No matter how much you say, I am saying that Put 20 instead of 10. Put 100 instead of 20. Let's put infinity instead of 100. The answer will remain the same, 1/2 omega l² someone He said that if I put infinite then first Think practically, apply a little infinite road This means there is no space in between It will not remain completely green, will it not? This thing will behave like a disc Even if it is correct, the formula will remain the same. What? Yes, even then the flower will remain the same. 1/2 bgl² l is also called its radius. confuse Don't be. l is also called its radius Is. So in these short if the disc can also be rotated Even then the formula that comes to you will 1/2 Induced emf of this disc = 1/2 b Omega l² = We have written r². r ie That will be the radius of this disc. did you come Got the point? What will be the direction? Fingers in the direction of velocity. B's Curl in that direction. thumbs up to you Will give the direction of the positive terminal. Perfect son, the matter is settling in my mind. I told the whole story. Motional emf, Rotational emf. In rotational emf, first Rotating Road. Then a lot of rotating roads It will come together. And then this disc will arrive. Also formulaic as it is. Previously BVL, now 1/2 B Omega LL². Now coming to the questions. The first question we face is that There is a metallic rod whose length is l. The induced emf will be rotated with an angle Angular Speed ​​Omega Normal to the Uniform Magnetic field b axis passing through one of and and is shown in this figure the Induced EMF is asked in NEET 2022 There is a question. Look at it very simply. a road This road is moving at omega speed. At one end, it rotates like this omega Still working. Tell its induced emf What will come? As I just learned, if a If the road is rotating then what is its length? l and omega rotating by 1/2 b omegl² and induced emf magnetic How much is the field? b so 1/2 b omega l² Find its induced emf according to Will go. So the right answer is being made from here Which one? 1/2b Option bun with omega l² 1/2 b omega l² c Will go. Look carefully once. look carefully Take it once. One of our NCERT There is a question. Example number seven. A will with a 10 metallic spoke. Oh how many Also spoke. The answer is going to be the same Is. We already know that, brother. Now we This is the thing I have learnt that no matter how many Whatever is said, the answer will remain the same. One-time proof Write it down. This is an NCERT question, so It is necessary to write proof in this. 1/2 omegle² This is going to be the answer. E-net also E-net induced for that circuit for that entire The entire structure will remain the same. 1/2 omegle² ok? Its length is given as 0.5 meters Is. Rotate with the speed at 120 revolutions minutes. These are a bit strange things. So We have to solve this first. The story doesn't run in minutes on Revolution Is. Ok? So instead of revolutions we take 2π We will multiply by. We divide the minute by 60 Will multiply. Meaning, instead of minutes, we Will keep it for 60 seconds. Our answer will come soon. in seconds per radian. The rest of the story. Horizontal component of Earth's magnetic field Field is given is a point for gos. Goss The story won't work, boss. So what are we do? convert to Tesla He has already told that One Gos = Sir, we also wrote 10 to the power -4 Tesla. Solved and what is the induced rime between this axial and this rim which Net magnetic field produced net Induced rhythm will produce this axial And that's what it would be between the rim. this thing is We knew it. Ok? Just solve it now Are. Let's simplify. look carefully 1/2 As It Is. The value of this four is 4 * 10 to Power-5 will be written. Look at the value of Omega. 120 revolutions means 2π divided by 60 We will make the minutes 60, meaning 60 instead of minutes If you convert it to seconds, it will come to radians. This will come in seconds per radian. And l means to5 means 1/2 and its square Done, now just have to simplify from here 2 4 means they can fly from there also These four and these four can fly from here These two two can blow from here 60 and this We will come from here so pay attention. If you look at it from the right, this is 2π 2π 10 Ray to the power - 5 This answer will come in volts. This is in volts The answer will come. Now you will simplify it, see 10 to the power is -5 and 2 is the power of pi. The value is 3.14 3.14 to two Multiplied it will become 6.28. 6.28 * 10 To the power -5 volts will become its answer. Will you be able to ask such questions, son? Once You just have to fit the concept intelligently. In the mind. Then keep asking such questions Go on, keep doing it. There is no shortage of questions Is. Very good in your NCERT dear I have given the questions. Once by himself he Solve it too and let me know what is happening Are they getting solved or not? These Well, you should ask questions only then you will get The idea will be that yes we can do it sir. further I have a question that you would like to ask me in the comment section. I have to tell you. And that too right now. What WILL Oh my God. This is the same one Is there any question? There are 20 metallic spokes. No. This time the story is a little different. each 1 meter long is rotated with the speed 120 RPM. 120 rpm means little by little Is it the same story as the previous one? RPM I have given it. Ok? Revolution per minute, that too That's what happens. Perpendicular to the Magnetic Field. This is also 0.4 gas. just here Confusion means what has changed? Take number Off spokes have been increased. 10 became 20 and The length has been increased to 1 meter. Now solve Do it and tell me what answer you get. Tell us in the comment section about this ABCD Which answer is coming from this? asked where Is the question gone? asked in neet 2020 There is a question. Your NCERT Questions Look at this and see this. Majorly Same Same This is a story. So whatever you have, That is Brahmastra. Where to ask questions First do NCERT questions. that is a Truth. That you should do those questions first. Read it. If you study directly from NCERT then there will be difficulty. Will come. But read the questions from anywhere. Do NCERT on priority. Ok? Whose story was this? Motional EMF. rotational of the emf. Now I am going to tell you something new. that if there is any coil in it, then the current changes If it does, there is an effect. the effect of which We call this inductance. This protest That's the point. This is according to Lenz's law. Is. that if the current is increasing then this coil Isn't it true that she herself would want to reduce this current? Any coil or any human being can Registers the change first. I am spoiled I am here, I will not spoil it. I am improving Yes, I will not improve. As soon as these coils inside If the current is increasing. So to reduce the current He will try this. So the opposite for subtraction Opposite to decrease in direction An induced in direction The battery will arrive. Also called back EMF Are. Also known as back EMF We do. Ok? I mean, you just understand that That this induced EMF will come. here Look, the current was decreasing. The current is going But this current is decreasing. So these coils It is much more than the number of turns. Koel will try to support him. These Koel is there to support him. Will make the current flow in the direction. like this will make the current flow in the direction that it She is supporting it. Ok? These It was induced. This was induced. So a coil made up of many turns which will be called an inductor which will be called a coil made up of many turns In the inductor which will be called an inductor If any change comes then oppose that change What does this self-inductance do? Sir, the phenomenon of varying current in A circuit produces an induced emf in In a same circuit means change within yourself Because of this, induced EMF is coming inside you. Is. The phenomenon we call self-inductance Are. It is called self-inductance. Self Induced emf is called as a back emf. It is also known as back EMF. And what does it do? Oppose Any Changes in a circuit in a s in a current in a Circuit. Meaning the change that occurs in your own circuit He is opposing it. own in the circuit. The first type is written as own circuit. right now in someone else Change will come. But first, let's talk about your change. Let's do it. Ok? a little basic This is its formula. What son? That This is the coil. This is some coil. start start start start start start. This is some coil Some current is flowing in it. I and this The current is increasing or decreasing. As such Let's assume. This is the current, it is changing. Veriri is doing it. So because of this current The magnetic field may have changed. solenoid In a way, it is a solenoid inside. So Solenoid means inductor. of the inductor magnetic due to increased current inside The field may have changed. and this magnetic Due to the change in the field, magnetic There must have been a flux change. So sir change in Flux is directly proportional to the Current. Magnetic field changes due to This change happened from. I Changes Due to which the magnetic field changed. And because of this magnetic field, flux The phi changed. So the magnetic flux is directly proportional to the current flow in this Circuit. Now find the sign of this proportionality. To remove this, we introduce a constant We do. This constant is equal to This is known as self-inductance L goes. This is just the first formula. One The first formula for self-inductance and many Work formula. You will need this formula Accordingly, or is it okay, the second formula is also Let me tell you. According to that second formula Dimensional formula of self-inductance Let me know in the comment section. Tell me your dimensional formula in the comment section. I have to tell you son. This is your right now There is work. The rest of the story. Look at this, we Let's do differentiation. means that di / dt then Here l will remain as it is. is constant. di / dt these for whom Does it depend on the parameter? Now! I will tell you a few things. But first, You will learn how its formulas are made. Are. So these short di / dt are induced The emf will be called di / dt. I write dt Am In mode, this is / dt l / dt Two flowers are being made near us Are. An induced emf = l / dt and The induced emf is derived from the flower is the flux. Then the flux b = l * i l is Is? known as self-inductance Is. Its dimensional formula comments section I will tell you right now son, this is useful. These This is a question asked once in the boards. Whatever the boards may be, but at least once Question asked in your boards It must be so because it is a very famous question. Is. Dimensional of self-inductance Formula. Perfect it was, even to the point. Now, we have two or three small questions. Let us do that on the basis of self inductance Current in a circuit falls from a 5 ampere to 0 amperes. There is a circuit in which The current situation has shown that this is no What was the initial current in the solenoid? Earlier the current flowing was 5 amperes. So Went from 5 amps to 0 amps. How much time did this incident take? 0.01 second It is installed. Average emf 200 volts Induced. The EMF induced by this incident What I have got is up to 200 volts. So tell me that Estimated self-inductance value How much will it be? Meaning of self-inductance What will be the value? So very straightforward Is. We just wrote about induced emf. Since the EMF is given, write the same. It is a more sensible thing to do. Divide by di / dt What else was there to write in the story? Value of induced emf = 200 l as it Is DI means it will be divided by 5 - 0 This will be written as 1 Meaning it will go up this 200 L * 50 * 4 = 100 then the value of L will be 4 Henry. One remember the thing that We call this unit of inductance Henry. Who do we call? Henry. you first Its Figure out a formula. Dimensional Formula Take it out. Then we call it its equal. Henry. Henry is the unit of this Inductance. Such a unit can also be called This. Perfect even things. did you come Do you understand the calculations? We Henry. Henry is represented by H. from H Let's represent. Henry. Henry The name of the scientist was. Due to which it Inko Henry. Like coulomb is the unit of charge. Similarly, the unit of inductance here is Will go Henry. I am here. Did you understand what I said? You are not worried about what new things will happen. Terminology is coming. No son, brother, work A matter of. Henry for Henry, the answer is Will go. another question Of NEET 2016. You try it for the first time. We will try it together next time. That is a solenoid with 1000 turns. When a current of 4 amperes flows through it Magnetic flux linked with each turn of a Solenoid is so. than self inductance How will it be written? Read it, public. What What is asked in the question and what is said Has gone? Sir, it is mentioned in the question. That a long solenoid has a 1000 turns. There are too many turns. Current 4 Ampere It is flowing. Through it. The Magnetic Flux linked with each turn of the solenoid Is this. The self-inductance of the solenoid. How will this story be written? Look, first So we can also give a formula for a solenoid. Will drive. But there is one small thing That The number of turns of solid is given and one Flux is provided for the turn. So flux What will be the total, sir? total flux Equal to number of turns into each Whatever will be the flux of the turn, it will be n i.e. that 1000 1000 * 10 to the power -3 * 4 so four Weber will be written. Yes sir. and Flux 5t equal to we wrote l * l so four gives us We have to find out and the value of the current has been given to us. is 4 amperes. Just do the cutting and beating. l = 1 Henry, the answer came and according to the options it will be correct from um 1D Vo option will be perfect. Look carefully. Look carefully. These are small questions but one at a time. Such works should be remembered. are you watching No? These are the questions asked in NEET. Meaning Even in our examinations on a small scale Such questions can be asked. Ok? This was a story of self-inductance where But flux is given or induced EMF is given. Now for the solenoid we I drive it specially. this question He is very famous. The derivative is the derivation number In self for three key solenoid What will be the formula for inductance? So First we will learn to write flux in that The flux total of this solenoid is equal to b. It is written by doing. ok sir, that's it Correct. Number of turns Suppose its is n. So b.n * a will be written as We, sir, we Magnetic for solenoid The field μ0 * n * i in this solenoid Current i is flowing due to which here The magnetic field is written on Magnetic field b = μ0 ni μ0 ni ok number of turns n area as it is Do we know one thing that the number of The small n in turns is the actual Am I in it? small n is the total number of There is length on the turns. So we wrote down n / Length. So it's written Sir μ0 n / length i and this It will be written as n * area. These cross sections The area which will be there, write that area. Will go. Yes, great. We get the flux t = l *i Used to write. Cut and beat the i from both sides Give it. So the formula for inductance will be μ0 n² for self ah solenoid μ0 n² Note here nn² i cut off Here area divided by length is self The formula for inductance is coming and this telling us one thing that Sir Self inductance is that of some other external factor pe depend na ho ki this whatever coil The shape will depend on its parameters It will depend on the end size. medium It will depend on pay. The geometry of this coil It will depend on pay. See number of turns Permeability of the medium And area and length have been used. So Self-inductance of a coil is depends on its geometry and on the permeability of That Medium. Here if any medium fill If this is done, then μm will come to its own In the flow of inductance. I am coming to understand In? This is a useful flower. Remember this too Yes son. Yes. I'm saying this for the first time but This also has to be remembered. Drive whenever you want You can do it too. small if you want It will be done in two-three steps. But things You have to write that this is this thing. Explain Have to do it. If you want to drive after that This question is asked in the examination. So. Perfect even thing son. is coming Do you understand these things? Yes. Ok. Now look Tell me one thing. We have some current here. If there is a change happening. If there is some change in the current If it is happening then opposing inside this coil The factor is coming. It is because of which We defined self-inductance. Yes sir. Which was called back EMF. Self-induced emf is called back emf. They say. So this opposes change. If current flows through the battery then Instantaneous current which increases It changes the current Inductor. Do you understand one thing? that this change has the opposite effect of this change She must also be doing some work. means that The battery must also be doing some work. In the inductor. These inductors that change flow I was spreading the word that brother, whatever current comes, I So it instantly flows means opposes I will do it. So this battery is something opposite to this. She must also be working. And that task d means d I wrote to power although he I would write the work to be done in the red form. I am, that is, I write in the form of power. So power is equal to the potential difference It happens by introducing current potential If you don't want to write the difference then write it like this. The induced EMF that will be occurring is opposing neither the induced emf E I wrote 'ka' and changed it to 'i' by changing it to 'intu'. Who The induced emf is opposing it No son, this. So l is opposing di/dt This was it. The battery that worked opposite to this The same work would have been done in this inductor It must have been stored. Brother, this person who is protesting To calm it down, the battery also So some work must have been done and that same work i.e. In power form, I have written power = E * I acts in opposition to the induced emf If it has been done then it has been written by adding E * I. Ok? I have written this in the rate form, so dw /dt and this is what this inductor does Must have been stored in the form of magnetic Field energy dw / dt dt dt cut dw = l Look carefully, we are going to integrate it. I am going and I have done this work, a small work. Done is what will give us value Energy Stard What energy is dissipated in this inductor? The energy that was used in equal to this work done will be The same energy is stored in the inductor Will go. So take out the l I di l i di then it will be sir 1/2 means l actually It will be written like this, right? l i² / 2 will be written as 1/2 l² 1/2 l² These Energy Stard This energy will become stagnant. look carefully Take this. This is a great formula that a magnetic field in the form of Energy is starved and that energy is written It is in the form of 1/2 l². very cunning This formula is a very useful formula. Memory Keep this energy safe for the inductor There is a formula. 1/2 l² l means self Inductance. I of the current flowing We have written the value. Correct? even Did you understand, son? Now here it is The story doesn't end there. This is us, isn't it? Trying to relate it a little bit are from electric field energy. do you remember If yes, then the electric field energy is written as The electric field energy was written as In childhood. If you remember, look carefully at Any electric field is flowing. Wherever there is an electric field, this The energy of the electric field is stored Is. Although we will talk majorly about capacitors. used to do. This is positive, positive, positive positive positive and here this negative negative negative then positive This field is traveling in the negative. Okay sir, so for energy starved capacitors used to write 1/2 such that q² / 1/2 cv² and if the energy density We talked about energy density, so we wrote energy density used to do 1/20 e² Something similar is going to happen here too Is. Wait a little, wait a little. Did you write Energy Stard? Later I will read the question. Let's talk about the work first Sir Energy Stard what did you write? Energy dissipated = 1/2 l² for inductor. l Pick up the value of solenoid value from here that we're writing for the solenoid. So The value of 1/2 l will be μ0 n² / Length into Area. The value of i is here I make it from. Look carefully that this The value of i = b / μ0 * n will be such that b / μ0 n / l we sir so i is squared so b² square of length divided by μ0 Square and capital square of n Do the cutting and chopping once carefully, oh do it son n² n² went once length once length Went. The μ note was there twice, here it was there once, flew. What is left? Sir, one from here. b² from here so 1/2 B² a μ note from here will also be saved. Hmm, write it down nicely. We give. This will come a Bar μ0 into area and this length. Hmm. This is the formula of Energy Stard. If I I write area into length as volume. Is it actually there? These cross-sectional This is its area and length. So the cross Sectional Area Into Length Volume Bun Will go. So Energy Starved Volume on On Volume this becomes b² / 2 mute and This is what we call energy density. For the magnetic field. b note b² / 2 Mμ0. So there is a question in our NCERT that obtain the expression for a magnetic energy stard that we Previously driven in a solenoid In terms of magnetic field area and In the form of length. How does the Magnetic Energy Compare with this electrostatic Energy? Which gives us magnetic field energy It is obtained from electrostatic energy What kind of relationship does it have? These There was a question. So first we have 1/2i² The formula that was just derived, Made after formula. Self-Inductance What we wrote for the solenoid Applied. Magnetic field μ0 ni Solved the substitute here. Us The answer that you are getting at the end, son, is that Energy star is available. Energy Vol. on Sturdy. Energy Starved This One The answer has come. Then the volume on the energy stard Which is called energy density. b² / 2 mμ0 It's something like 1/2 1/2 e² over there Was. Here is b². Then there was the Apcent node. Here μ is 1 / μ0. what was there Some analogy of her was sitting here Is. So this should also be a comparison between Went. A small derivation also took place. These Both the flowers are also useful, son. remember Don't forget. This flower should not be forgotten To you. Understand derivation also once. This way Questions can be asked. and even one This question has appeared in CBSE many times. This question has already appeared in CBSE once. Is. Ok? Even the incident Problems, any troubles, son, till now We talked about changing our own current. Because of this, the incident was happening within itself. Now no one There is a change in the current of the adjacent person and The flux of ours is changing. As such How can this happen? Observe carefully if I will change the current of this one. this forest If I change the current of the coil then this one Due to change in the current of the coil Does One Walli's magnetic field change? Will you do it? Yes, this is correct. If the forest If the magnetic field changes then its Because of this the flux of the other coil changes Can. Yes, this is also true. Attention because magnetic field lines There is a change here, which means it is magnetic. Field lines extended. Suppose that right away It increased. If it suddenly increased then the other one It is going into the coil also. Look at the other You should also pass in the second coil. Has been. Then the flux of the second coil Change happened. Then the current of the first coil The flux of the other coil changes upon change It has an effect. It works, son. then others Flux of the second coil Flux of the first coil It is dependent on the change in current. Dependable means that he will change, so here But the flux will change. Now between these two A constant is written in and that The constant is called mutual inductance. is that due to the change in the earlier current There is a change in flux in the second coil. The phenomenon we call mutual inductance It is called an incident. The Phenomena of Inductance In an emf in a coil due to changing Current in neighboring coil. Now because of this Here one induced emf will be found and the other in the coil. How? Differentiate it. Differentiate will give you EMF induced in a second = m This is written as di1 / dt i What did you understand son, but this one There is a formula, it is very famous. This one The formula is very famous. Derivations from here They come at a very dangerous level. terrible level Meaning two or three derivations are very famous. One Coil-in-coil and a solenoid The one with the solenoid inside. These two derivations He is very famous. Ok? I understand. See The first derivation of this case is probably this Derivation number six is ​​not. It's five. Derivation number five. Ok? do this by yourself take set means whatever the order of derivation is They. Due to the current in one coil, the other coil There will be a change. So what do we do majorly? Do you know? Whose magnetic field should be written? Is it easy? It is easy to write both. Us Know that there is a circular coil. circular The magnetic field caused by the coil hai woh we can write this is equal to μ note μ0 You used to write like this, right? μ note / μ note i / 2r would be such a formula Is. If the number of turns is n then I will multiply it. multiply by n Will give. This was the formula. Yes. If Look at the magnetic of the first because of the second If you write field then it is possible that there There should be variation because variation is on a large scale. will be. I assume that the current in R1 is flowing and because of that current R2 Changes are coming in. This is too much to write It's easy. So sometimes such a thing may happen So the bigger one which causes the magnetic field Fields that are easy to write and constant Keep writing. Initial is fine. So sir The current flowing through it is equal to i1. Number of turns we take it to be n1 So here at the exact center The magnetic field will be written as b1 = μ0 i1 / 2r1 and number of turns from n1 then n1 We multiplied it by . perfect Look carefully now. Because of this the current It is flowing in direction. I Direction or I of the magnetic field Direction of magnetic field due to one. Due to one. So B1 we have written. This Flux change due to magnetic field It will be in the other coil. So it is written We turned B1 into the area of ​​the second coil. Of. Hmm. And let's say the second one The number of turns in the coil is N2. So write this I took number of turns N2 * area A2. That's the end of the story. Yes. Look carefully now. B1 = μ0 I1 / 2R1 We wrote N1 then N2 as it is And the area in this story will be written as Pi R2 We wrote down the square area of ​​π r2 If something is happening, we fight I don't think anything is happening. Okay, no problem sir. Flux 2 What Flux 2 equal to we learned to write l * i1 We are just having a fight. i1 i1 It's getting cancelled out. I will not come here But m used to come. I just learned it, son. We are talking about mutual inductance. So Mutual inductance into i1 of the other Change in flux due to previous current This is happening so i1 has come. so m ah i1 i1 Cancelled out. Mutual Inductance of This coil is in between these two arrangements. Mutual inductance Aya μ0 i1 cancels out happened n1 n2 π r2² will divide by 2r1 these mutual The formula for inductance came. no longer necessary That the number of turns has been given to you. As such It is not necessary. I am just a Take the hypothetical case that the number of turns I have given n1 and n2, so I told that story Has been taken forward. Look carefully at this To the derivation. I did it in two or three steps It has been written concisely. When in actual When you write this, please elaborate a bit. For the first coil we have calculated the current flow The car is i1 due to which the change is coming so much in the magnetic field that due to Changes may be coming in the flux. which flux For i1 we can write m * i1 i1 i1 cut out and mutual inductance We have got this much formula. is coming Did you understand son? someone to worry about The thing is? Write the derivation properly first. understand. Understand each step and why The next step has been done. perfect? This coil There was a coil incident inside. see the first one We have written in respect of Coil. First Made current flow in the coil and its That's why magnetic field is written. don't make the mistake Do it here. Ok? One such bean The question was asked in NEET 2021. In NEET 2021. need to calculate No, there is no need to even pick up the pen. What we understood is the same question. that there are two conducting circular loops whose Radius R1 and R2 are placed in the same Plane with their center coincidence. Meaning The centers of both are exactly center to center, meaning The centers of both are getting aligned. same as that Like the story we used. Ok? R1 very is higher compared to R2 that we had already predicted and from this We had found the answer. Ok? meaning which The story we read is his. The Mutual The inductance m between them will be directly Proportional to. Now Mutual Inductance To whom will it be proportional? m from whom Will it be proportional? who just read the story as it Is as it is, the formula I am getting, sir R2² is proportional to R1. You should however This will have to be derived. But right now we just I have come by deriving it. So it's clear straight away R2² / R1 will become the final formula and Its right answer will become D. Write it down, son. Take a good look at it once. So, son, The right option will become D. Now a new Moving on to the concept. One Mutual Inductance So far we have given the formula and made a derivation which There was a coil inside the coil. I second Told that a solenoid inside a solenoid There is also a very famous derivation of type and your It is asked in board examinations, son. So there is a solenoid inside the solenoid then these How to write the mutual inductance of both Will you go? Like this is the first solenoid. These The first and largest solenoid. be careful Look, son. This is a solenoid. Second. It is inside this but it is small. This small Of equal length. this little solenoid and This is of equal length. Ok? Look numbering Do it. This is important here. This small Is. Whatever its area will be, it will be small. It will be written and this is the first one. Number one. We're going to write mutual inductance. Then we have to write that the flux varying on a two due to one due to one magnetic What does field one mean? magnetic field Due to one or due to one into tax area Of that two. A small formula. Yes sir. See how much magnetic field one causes Will it be written? Meaning, understand A one in this one Which one is it? This is the big one, that's the forest. Ok? So because of this big one How much magnetic field will be written? Attention To see from. Sir that formula = B1 = μ0 * N i will be written as N1 * i1. Ok? We have here But substituted Sir μ0 n1 * i1. And Area of ​​that two. Now look at the total area. We are talking. Total area. so one The ratio of flux of one turn to the second turn to the third By adding all this, you will get the area of ​​the turn. Number of turns n2 into a cross sectional area a2 That's right, even look carefully at this point. Make no mistake about this. Written by Area Two Will go. I am writing about the smaller one. We. Great sir. Now simplify the rest a bit. We do. See μ Not As It Is. N1 / Let us write its length as L. into i1 This will come to N2 * Area 2. looked carefully Go. Ye 2 = What is actually written Is? m2 * m2 * i1 is written as this sir. Excellent. Now get rid of this from here. Forest One will cancel out. Mutual Mutual inductance M is equal to We will have the formula ready, son. Note N1 N2 OK. Ah and it will become n1 here n2 that area to area 2 Divide by Ah i1 then died. Yes, this forest Died Divide by Length l Ye Mutual What is the formula for inductance for? This means between these two solenoids If two solar panels are placed in the same orientation, then at that time Pay mutual inductance from this flow This flower will be represented, remember a little There is a need to keep it but majority case I don't remember, I can remember, friend. Phula is a very good thing, I can't stay So what we do in that case is There is a little derivation, understand it well. Whenever needed, we acquire expertise Let's do it. So quickly, quickly, quickly, derive can that magnetic field due to one into tax area total of a to simplify The result is in front of you. I1 I1 Both I will die. This mutual inductance is found Two for Sollened. Now here in mind It is a matter of keeping it like self Inductance also depends on geometry. Was. Yeh Bhi Geometry Pe Number of Turns It depends on the pay. and between the two What is relative position? This on that too It depends. So mutual indifference What all things does it depend on? words I will remember these things because MCQs I get asked a lot about geometry. It depends on the number of coils. of both What is the relative orientation of the middle? on that It will also depend. Number of coils n1 n2 per Also depends on the separation and medium It also depends on these two cells. is the mutual inductance. keep this in mind Because this thing is asked a lot in MCQs. Is going. There are many of these in MCQs. Things are being asked. and a famous The question is whether self-inductance and The mutual inductance between the two Tell me the difference. It is asked for two marks. Is. Even though CBSE is very old I have a question but about the latest trend. This question is also being asked accordingly. that self-inductance and mutual inductance Explain the difference between. So what we read I have to write the same things that self-inductance of current in its own coil We get it because of change. Whereas Mutual inductance is the product of the inductance in a coil. due to change due to change in current There is a change in the flux of the second coil. Because of which we get it. because of which We get it. So here we are talking about two coils. Is. Here just because of myself Change which is called self. whose name Does exactly what it says on the tin. Self-inductance Majorly the shape and size of that coil pay Depends on the number of turns It depends. Number of turns is high Is. This means that the self-inductance is high. Whereas these are between the two coils between the two It also depends on the separation. over there It also depends on the medium that both What is the medium field in the middle? So this It depends on things mutual Inductance. small in two marks This question can be asked. Shorted Even the story we first read Experiments of Sir Faraday. than that First flux experiment by Faraday sir After this Faraday's law and then Lenz's law are complete. The phenomenon was electromagnetic induction of. After this we have motional emf, rotating EM and then this inductor story in which Self-Inductance and Mutual Inductance I have read it, son. Ok? Ok. in a single slide If I get it revised properly. One There is a small thing in between. of inductor If series connection comes then L1 + L2 + L3 Plus series connection as in register It will be written as it is. and parallel connection one It will be written from the game of Upon. This though It has been removed from NCERT in the boards. There is no need for this. But still, never If a small question comes up, you You should remember this. This in more detail I did not study anyway because here There is an effect of mutual inductance. Mutual inductance means that here this These coils also have some reactions among themselves. will cause mutual inductance do you get. So this self-inductance There is a formula which has some corrections. And corrections come at very severe levels. Are. Because of this, the combination of inductors We don't read much. of capacitors You have read the combination. of the register You have read the combination. But the inductor We will not go into much detail about the combination of Reading. This is the only one in the series with summation and The game above will be in parallel. just this much It's a thing. We are not going too deep into this Go. Well, what I was saying was that Let me revise that in a slide. When does this electromagnetic induction occur? We had it. Either the magnetic field should be very Needed This coil is what we used to write as flux. They were there, right? What did we write in our childhood, sir? Flux used to write. look carefully at that What we used to write was Flux Five. is = β cos theta then either area variary should I do it sir The magnetic field should be varied here. Or should theta vary then majorly case In this we also measured the magnetic field by varying I have seen it, I have also tried it by doing area verification. Now theta variation in rotational motional emf is I am looking carefully at this coil. whose area is a then this area vector It has come out and it is rotated at some angle like this Used to be. Look carefully, it's magnetic. Field creeping in and area here He is continuously doing very. No area But Theta is doing very due to which The effective area is increasing and decreasing. As That a coil is lying right in front of you. These The coil is lying in front of you. to suppose This is the page. Coil the page for a while Let's assume. Now this is from the magnetic field line She would enter through the board, sneaking in. And this is the coil, it is rotating like this Is. Shar Shar is rotating like this from the beginning. I took the circular we are using. I have placed the circular here in front of you. It is of rectangular type. and its area How is a vector? This is how it happens. So look It is perpendicular to the surface. so such It is rotating along with it. Ok sir. So it is rotating and that too gives a speed I have kept it for you. He does it with velocity The area vector is varying. Sir Its rate of variability is θ = Omegat is. θ = omega is the rate. As That area vector is rotating, isn't it? The rate of occurrence has also been told to you that θ = omegat we just substitute this In the equation. As such we have the equation becomes ba cos omegat look carefully whether this Flux is varying yes sir on time Dependable Flux is this, it is time dependent. Flux is a special case meaning till now we This is the third case in the one you were reading. three case three that in which theta Vering Theta is doing very cosomegat watching desensitization are doing. d /dt db /dt Look carefully. If its number of turns is n. I assume that means The number of turns of the loop is n. So here n It will come in multiplication. Here n comes will go into multiplication. We do denunciation Have been. Look, I took the nab out. di /dt Whose term have we written? cosomegat The value of is written. Just look carefully. Now let's do the distinction. What will you get son? See. No will also generally remain outside. cos The differentiation of is -sin so this -sinomegat and d/dt is the differentiation of omegat Differentiation will be done once more so that We will get the denitration of omegat as omeg. So Here I am getting an Omega Extra One Getting Omega Extra. whose equal Has the value arrived? di / dt equals the value I Is. Now look carefully and see the induced emf. We used to write in our childhood. Sir, -dfib /dt. Minus Minus will die here? it will get 0.0 ... Yes sir. What's new in this? If the current even then we will be able to write, current I induced equal to emf induced Divide by resistance R. We will be careful sir. nab omega / resistance r this will come out to be sin omegat sin omegat perfect in this no story I mean, there's no difficulty in my opinion. It should be, but still, take a look. cos omega is the number of turns if n is Total flux will be written as this total flux will be written The total flux is written as n times cos n omegat difference differentiation we did so Sir, we have got negative sin of cos And according to the omeg chain rule, omeg was also found. Is. pulled out omeg nab omegs sinomegat ok now you can write it like this also This is nab, it is a constant, so this We can define a constant as its maximum value. Also treat. Ok? Well, let's leave it Are. I will explain this meaning later. Induced emf = 0.05 sin(omega) if Its rate is changing according to omegat. It is there. And the induced current equal to is written will divide by R induced emf Divide by R. So 0.050 ... sin(omega) is what we get induced Current. Ok? Let me tell you one thing. This is the complete concept of AC. of the generator. Theta Varying. means that we You can get current. if by any means Any such coil in a place with a magnetic field Let us continuously rotate theta By angle or by omega rate. Yes sir. This is true. in some way We wanted to rotate this armature like this. By producing magnetic fields, large I kept the magnets, I kept the magnets because of which There is a magnetic field there. and his We trapped this coil in the middle, a to such an armature, to such a turbine that placed the armature which continuously It is rotating at the rate omega t. So sir, This will be a phenomenon. And this phenomenon Accordingly, you will get induced current and Induced emf will be obtained. And according to this will get. Yes sir. Then in that case you Induced emf and induced current will get. You can write like this also. induced EMF = E note sinomegat will be obtained. And induced current Induced current = I note Sinomegat will be obtained. Where someone asks you the value of E note How much is it? So the value of E note is 0.05 The maximum value will be called 0.05 The value is the maximum emf. and I e What is the value of the note? Of note Value E note by R means 0.050 ... R is the value of maximum current. Yes sir, did you understand? So somehow We need to rotate this armature. So that's it The concept of rotating the armature, i.e. AC generator. So this is a very wonderful topic. This The hot topic of the chapter is AC generator. Excellent. Ok. Let's see what you understand. be careful Understand. First, what does its principal say? First, what does its principal say? That Theta should vary in magnetic field This for loop then there you have induced EMF and induced current will be obtained. then someone This is how we have to rotate the armature. so such There can be many plants. Such as This is a hydraulic generator. because of the water The turbine is rotating and the armature is rotating Is. Magnetic fields we have North and South Poles are generated by placing such large magnets Done it. So this turbine helps the armature and the turbine can be rotated by water Change is happening due to kinetic energy Is. Meaning it is rotating. Second thermal generator that we got such coal from somewhere The fire burns here from the system, meaning like this This means that some steam is produced which The steam is coming at a very fast speed and is turning this turbine. look back Here it is, turning this turbine. So because of Steam, because of Steam The turbine is rotating. How was this steam created? Was it for water? Sir, this is made from thermal energy. Has been. That's why it is made by burning coal. Yes sir. So see why this turbine rotates. Are you getting it? Thermal energy due to steam Hence the name of the thermal generator because of Has given. Wind mills. Best example sir. Best example windmills that wind here turbine due to the kinetic energy of will rotate and this will rotate the turbine armature And inside it, both sides of the armature are like this There is an arrangement, there are big magnets Due to which there will be a magnetic field. So that's it We need to mechanically move this armature in some way. Had to rotate. There could be many such ideas. and it might be on your mind too There are many ideas for this. Comment Section and in what ways this armature can be rotated. I do this by hand I will turn it around, sir. It is possible This is also an energy is the method of. But show your Creativity in the comment section. then someone If we want to rotate it in a mechanical way then We have made it rotate with energy. Here you can see the hydraulic and wind mills. You can see the example. also from thermal energy We have got it rotated. So we have a The phenomenon of theta orientation has been found. electromagnetism The phenomenon of electromagnetic induction. Ok? Now let us talk about its AC What actually happens in the generator Is? So this is the armature. two big The magnets remained. And this magazine- these two There are small carbon brushes that The current that is coming out from here, We were able to see, understand or Could try to store it. or transmit Could do it. So here for the first time we have Noting the deflection, whether we Will I get electricity or not? So Koil It is a joint. carefully around this coil Look What is inside this coil, sir? A soft iron core is placed inside the coil It has been said that due to which a considerable In intensity you will get induced current. The magnetic field will be quite strong there. But. two large magnets due to which The stung magnetic field is produced. Soft iron core in the middle and surrounding it What is? is the armature. The armature that comes out He is having sex with two prostitutes. And here We can take out this current through carbon rust. Are taking it out. here in actual There is no galvanometer. But right now Galvanometer is installed because Because we want to measure a current It is being received and if it is being received then its nature What is his nature? in which direction Are getting? All that you need to know right now For this we have installed a galvanometer. So AC generator a device which converts the Mechanical energy. You learned, sir, that Energy from windmills or hydro energy from a power plant converts mechanical energy to electrical energy. electrical The last current you get in energy How much was he getting? I note Sinomegatt was getting as much as I could. Meaning You will get current while being sinusoly very that first sin is for half the time interval Positive again for half the time interval It is negative. So somehow you do that You can say that we get electricity here. and the direction of the current is continuous There is a changing direction. means these What if you get a short? electrical Energy. This is just mechanical energy Converts into electrical energy. Perfect thing even. Ok. Principal What is it? What we said earlier was that Faraday's law is its principal. Any Our aim will be to make Theta very effective. The flux b is equal to 0. We wrote 0.05 NAB cos (omega) Differentiation done. Differentiation done di / dt Simplified and tells you Induced EMF And induced current has been found. what we previously It is written in it that the same thing You get this flux that is time dependent Used to be. What are you getting? Time Dependable You are getting flux because of which you Induced emf and induced current mill Used to be. This has been its principal. It is basically based on Faraday's law. is coming Do you even understand this? Fabulous. See Now let us go straight to its working principle. I understand. did you get induced current Is. Induced EMF has been found. what happened sir In working principle? Working Principle If seen from this perspective, Sir, this rotation from theta angle. The head rotated. Continuously rotating. omegat rate It is rotating from . It is rotating. It is rotating. Due to which you Induced emf such that di / dt - di / dt is minus as it is d / dt fi's value nab cos omegat omeg will come out. cos of The differentiation will be minus sign. So this was getting nab omeg sin omegat This gives you induced EMF is found and if the value of sin is one or Then we can call this maximum value e max or e note that e maximum sinomegat will be written this induced you will give the value of emf and if I induced If you want to write then E maximum E note / resistance R = sinomegat This gives you You will get the equation of current and current here Here you will find out the sinusoidally very tax Used to be. According to which theta is happening According to that you will know the current very It is happening. According to which theta velocities will vary the current accordingly and We have already written the equation for current. that the current I = I not sinomega emf E = E This rotates according to the not sinomegat Will do. You know the time, that means you know theta. Went. If θ = 90°, omega = 180°. omegat = 270°. And omegat = 360°. So you will know son that this equation When do we get maximum emf and When is minimum EMF achieved? And Its direction also changes continuously. is according to sinusoidal equations. perfect. This was the whole story of AC generator. That's where you get the current. Sinusoidally varying is found to be This is what we call alternating current. whose direction changes continuously Is. So it's the little things that Alternating current can be defined as the current that changes the magnitude and polarity Regular interval whose direction polarity Continuously, sometimes positive, sometimes negative. Sometimes positive, sometimes negative. Polarity There is continuous change. him we It is called alternating current. where we The equation was written as I = I not sinomegat I note = NAB Omega by R was written. So this The I note, this I note is its The maximum value is called the pick value. Same with the E note. completion of the time period Time taken to complete the cycle This will be called the time period T. and time The equation for period is t = 2π / Omega and 1/frequency are also called time It is called period. Whose story is this? This is the story of alternating current. So This is the AC generator that gives birth to the next To the chapter. Chapter Number Seven Alternating Current. This gives rise to the following chapter. This is where the next chapter was born. Well, we would ask one small question at a time. Yes, it is Kamala Ben. Kamala Pedals A Stationary bicycle. Ok? Meaning The same story is happening in that pedal. See that the pedals of a bicycle are attached to a 100 Turn coil of an area. Keep writing down the 100 tons of things that you have given me. I have been. Correct? We were talking about hydro from power plants, etc., such as wind mills From here Kamala herself rides the bicycle on her feet is rotating the pendulum and the energy She is producing. Look, 100 numbers off Turns n = 100 tons. Ok. coil of a Area a means the area of ​​that coil is 10 meters Square. the coil rotates half of a Seconds per revolution. coil rotates at half Omega = 1/2 revolution per second. These If it is revolution then convert to radian If I do this, it will be multiplied by 2π. So 2π / 2 radians per second means it will come to Pi Seconds per radian. It is placed in a uniform magnetic Field. Give the value of the magnetic field B. is kept at 0.0101 [music] So I can write this Magnetic field B = 0.01 Tesla means 10 to the power -2 Tesla. carefully perpendicular to the axis of rotation of a coil what is the maximum Voltage generated in a coil? Maximum voltage i.e. value of E note We have been asked. What we just simplified Because I keep coming back to the same place I am not drawing a diagram. Although We can also draw. But what we I have used it, meaning the coil that was just rotating Because of this we get induced emf. and that was the equation for induced emf It was like this E note sin(omega) E note What was the value? NAB omega sin(omega) So what is the maximum value? NAB Omega. Maximum value is what we get The peak value has to be found. So NAB Omega has given N number of turns. Yes, give I have kept 100. The area value is given is 10, that is, 10 to the power is -1. of b The value has been given. Yes, I have given this 10 Ray to Power-2 And the value of Omega has been given, please give this also. I have kept the pie, here comes the pie. So 10 to the power -2 +2 From here it became a cut pit. This 3.14 then that This will become simply 0.314 Ah, the answer will come in volts because voltage Isn't it a matter of this? Maximum in induced I have asked. That's it, our answer has come. Please verify this. Maximum Voltage How much are you getting? 0.314. This is our Example means this example of NCERT The number is 10. Whose story is this, son? This whole The story has been electromagnetic of induction. where it all started Was? Just remember it once. where the beginning Where did it happen? We read at the beginning Magnetic flux b = what is it? We What is the flux b = initially? They I understood that we would write flux = b.A. Were. Then we have three statements of Faraday's Law Had studied experiments which also from animation We understood and how to write it. I also understood. Then according to Faraday's law We said that the induced emf is equal To can be written in minus di / dt I am not writing a minus. Although minus Who is the sign representing? Lenz's Law is representing the . Here the current For this also we had written induced emf Divide by r / r and the charge induced Was getting is equal to we wrote. Dot dt with induced emf. So delta We were getting the formula for phi/r. We wrote this according to Faraday's Law. Then we talked about Lange's Law. There is a lot of it in You asked good questions. Motional EMF I had read a formula. EMF Induced = BVL and the second one we have for rotating one Had read. 1/2 b omega l² missing formula What son? For inductance we have a Self-inductance l is read. Second The mutual inductance m is read. and AC EMF induced for generator = e Note sin omegt where the value of this note is written goes nab omegs sinomegat and current induced equal to i note It is written from sinomegat. completed this The whole thing was whose son? electromagnetism The whole point of electromagnetic induction It was electromagnetic induction. Now remember Yes son, I told you one thing, NEET A question of 2020 or 22 was told which The question was based on AC generator only. One First, give me a feel of an AC generator. I give. Look, I will show you an illustration. I will show you an animation that I will fall in love with. With love you will understand what it says. AC generator. due to some mechanical energy This coil is rotating due to which the front Current can flow in the coil without battery Used to be. How can this happen, sir? Because The magnetic flux is changing here. And because of that change in magnetic flux We are getting induced current due to which this The bulb is glowing and the bulb here Have you ever seen the AC generator that is getting current? Sometimes increasing, sometimes decreasing, sometimes increasing, sometimes decreasing is increasing, is decreasing because these We are getting time dependent current whose direction is continuously changing This is called AC current and this is what Here is the next chapter, so the beginning of a new chapter Only after this will I ask you a question. It was given in homework that this is for NEET 2022 Ask me this question in the comment section. I have to answer because here theta It was a very funny story. This is at 2 radians was continuously changing from second to second and You will get the maximum induced current in it. The value had to be told. I asked you this question I had given it as homework in the middle of the session. Now this You can ask your question right now in the comment section. Do it in and answer it. Ok Son? So that was the whole story. electromagnetic of induction. In which you first magnetic Flux, magnetic flux followed by Faradays Experiment, three experiments, then two Laws Faraday's Law, Lenz's Law which are complete About electromagnetic induction Was explaining. Then the story moves on Is. Motional emf, rotational emf, self Inductance, Mutual Inductance and Last AC generator in. Very short chapter, and He will give you four to five marks. So A small chapter, not even a single mark deducted. You have to take care of him. in short chapters It is easy to gain marks. This you You cannot ignore it and go on. On the way There will be many obstacles. like you Maybe some concept of electric field I don't know which ones are being used here. The same ages of the magnetic field are also not known. which are being used. But you have to You will have to face obstacles. For him You have to accept it and move ahead. then this You will understand the chapter well son. So No matter how many problems there are, fack it. go ahead. of your goal Be honest about it. Because your competition Son, sitting in your class 40 50 100 150 is not among the children. huge This is the number you will play. So this thing Keep in mind. If you already think so You think I am the topper of my class. Or I am the topper of my class. Not so Yes son. You just have 50 or 100, 200 children. You have remained a topper in the middle of . This number She is going to go to a very big level with whom Your competition is about to take place. So in the mind Sit down and have this mentality of yours Give it a bigger shape. Your goal is to Should be bigger. Lots of obstacles in the way All will come but face it and move ahead. Is it okay son? So with this, this Hum of Electromagnetic Induction OneShot We do Swaha. See you next time with new things With things. Till then son, Tata Bye-bye. Love you all.