Transcript for:
Light Concepts and Devices

Are you scared of science? hey but why To fear when your Prashant bhaiya is here. So hi everyone I am yours Prashant Bhaiya and I am back again with a new With a one shot and the chapter is named Light. Yes, this is the same chapter that you are scared of. You stay here, you stay afraid. Bhaiya Numerical If it could not be solved, it will be solved today. Brother this How to make a ray diagram? such a trick I will tell you that you would not have thought of it. Isn't it? So this whole chapter is funny in one shot interesting in a fun way I will ask many more questions in this manner. These question board in your exams Inside exams, inside school exams The chances of repeat are very high Are. Ok? We will do everything in detail. Is No? Just keep this in mind. Why to Fear When your Prashant bhaiya is here. Ok? Whenever you face a problem, your brother He is standing here. Ok? your elder brother He is standing here. You don't need that much load Is. I am. ok sir. what a very nice The banner has been made. Look how beautiful you look I have been. Well I am beautiful but Ok. ok sir. what are we doing today Are you going to? What topics to cover Are you going to? All the topics which you There are reflections in NCERT of Light, Spherical Mirror, Sign Convention, We will do numerical, refraction of light do. Then the lens will also read and power off The lenses are also completing the whole thing Will be. Ok? Will read it in a fun way. The notes will be uploaded to your Telegram. Or I can also put the link in the description Give. Isn't it? So take notes later on Watch the first lecture in . Later Notes download. Don't run after the notes right now. Isn't it? Well, I know those students feels the worst for the sit in class and make notes and When friend asks him brother notes If you give it to me, I take a lot of good photos and send the notes. But there, when he Students ask for notes from someone else. Isn't it? Brother, I did not make notes. If they give me the notes then there is no help for them Would do. Isn't it? I feel bad for them, man. Never mind, but I am a good person. I will give you notes. Come on. starting up Are. What is light? Roshni bhai our life There is darkness in me. Oh no, not in life There will be light for you too. First understand the light What is? So what is light? light is a Form of energy. It is a very basic thing. What is an Energy Key? There is a form. a big one Let me tell you a fun fact that light it yourself is not visible. That means we cannot see the light Can. We can see everything because of light Are. Did you understand it? Now look, the light Everyone will know the speed of. 3 * 10 Re To Power 8 meters per second. Small classes I have been studying since. oh in small classes So where did you study? No roast I am doing it, son. Ok? Isn't it? His Apart from this, light is in rectilinear motion She does. What is rectilinear motion? That means it moves straight. Isn't it? he too he is as straight as your prashant bhai At once. Ok? So rectilinear propagation That means the light goes straight. Apart from that, light can also travel in Vacuum. We already have small classes too inside the ninth class, inside the eighth class I had read it inside. Now comes the main Coming to the point which is reflection. Brother Is this about reflection? what is this new Is it a phenomenon? I said not much load Lenny. What is Reflection? tick tick tick Tick tick tick means bouncing back of light. That means the light came I I I I hit and went away Went. Isn't it? The light came, hit and went away. see Hey son, what is reflection of light. The Phenomena of bouncing back of light rays when they strike on the surface of a Object. Isn't it? When the light came, hit and went Went. Isn't it? in the same way as he too I came into your life, collided with you and She had gone away. Ok? same way the light too She came, collided and went away. Now, very basic stuff. You have already read it. If you haven't read it then tell me I will give it. Here is a ray diagram. Let me zoom in a little on this ray diagram. That will give you clarity. Look three Things happen. first happens Incident Re. First, this diagram looks clear Everyone is feeling it, right? Let's start with the incident. this which Hey, this is your incident. That means this came I I I. Ok? Now there was a plane here Surface. what was it son? Plane surface. on this She collided and went away after colliding. we call it These are reflected rays. what do you say? Reflected ray. now draw an imaginary line It is done. Isn't it? an imaginary line It is drawn and we call it Normal. what do you say? Normal. They What is normal? an imaginary line Perpendicular to the surface. this was the surface A perpendicular draw is made for this. You understand perpendicularity, right? 90° yes. so one Perpendicular draw is done. to him we They say it is normal. Ok? So three things are the reflected ray, an incident ray, and Normal. Ok? So these three things you Hopefully you should know that the incident happened What happens? what is reflected ray Is? Isn't it? And what is normal? What is normal? Imaginary Line Perpendicular to the surface. very nice Brother. These are very basic things. I He said, wait, have some patience. even tougher things right now I will show you. I will show you questions that Ditto are printed in the board exams. Ok? Come come. Look, there are two laws. Of reflection. what are the laws of Reflection? There are basic two laws. First Law what does he say? The law says that the angle of Equal to the incidence angle of reflection will be. Now you will say brother incident angle what is this? I say I will show you. Look, look at this diagram carefully. Angle What is off incidence? that angle which what is this line? Incident Re. and this What is? It is normal. This one in between You can see the angle, we call it Angle I. That means angle of incidence. Similar The angle between this and this is called It is said that angle r means angle of Reflection. It's basic. So brother the first rule is this It says that both the angles are equal Are. These will not change. Isn't it? this is yours Son, he is not like a friend. these beans will remain. These will not change. This is exactly the same will remain. Will not commit fraud. these two We will remain the same among ourselves. so the first law says this the angle of incidence is equal to the Angle of reflection. what does the second law say Is? The second law says that the three rays are you watching ting ting ting ting ting ting ting ting ting ting ting ting ting So these three rays that you can see right? All three will be brought on the same plane Bhaiya what is a plane that plane A plane is a surface that you can see All three of these are on the same surface. For example, suppose there is a paper. Isn't it? Paper above the incident ray, reflected ray and Normal. What are all three on the same plane? I will bring it. ok sir? So remember this Your Second Law Incident Reflected Ray And what does normal lay do? There is one right Let's fly on the same plane. Come on let's go Did everyone understand these two things? quickly Tell me quickly. ok remember one thing What is the josh meter in your lecture? They Yours should remain high. That is, energy What is a meter? Isn't it? So keep your enthusiasm It should remain high. when your master is here I can stand up and teach you with energy Is. So my friend, why aren't you here? Why are you taking the load friend? a little You have to maintain high energy. yes or else I roast you son, I roast you a lot I fight a lot, son, I have built my body I have built a body, I kill and I am I also keep a dumbbell so it has energy keep it up come on let's talk now of a new topic whose name means a There is a definition, there is a term called lateral What is inversion? What is lateral inversion? right and left and right means one go stand in the bar mirror go go Go quickly, go stand in the mirror Raise your right hand, which hand did you raise in the mirror? Did you raise your left hand or not? If If your right is taken away son then it means Either there is something wrong with the mirror or you, son There's something wrong with me. a little tantric Call him at home. Ok? Lateral Inversion What happens? a phenomenon in which When we see the right thing in the mirror, it We see the left thing in the mirror. Ok? So what? lateral inversion is the phenomena where left and right sides of An object appears reversed. Isn't it? Appear They reverse, that is, they become upside down. most of it Is this the biggest example? An example is the ambulance. the ambulance that would have been Isn't it true that 'Unp' is always written upside down? You If you have ever seen an ambulance then the one which It is an ambulance, they write it upside down. Do you know Why? Because let's say I'm driving a car Am. There is an ambulance behind. I am from the glass When I look at that ambulance I will see it in the mirror It will be visible straight away. Are you understanding? Isn't it? This Because of this, ambulance was written upside down in the ambulance goes. So a question is also asked Sometimes, sometimes. what do you mean by lateral Inversion? why is the ambulance returning Laterally inverted? why is it written upside down Is? so that the person driving in front can see the glass I look in and he sees an ambulance and he Give me way. Isn't it? hurry to the ambulance Hey brother, I have to go quickly. It is obvious. Ok? ok sir. ok now let's talk of plane mirror. the same mirror in which the right Of left, of right, yes the same one. so plane Mirror is there in all our houses. Some of its features Tell. Tell me your characteristics. Isn't it? What features can a plane mirror have Of? Come on come. A little bit of plane mirror Feature-variable play. look first bro All the images formed in a plane mirror are It becomes virtual. Brother what is this virtual Is? Virtual means fake. Please understand, son Type of Image A real image real image. A virtual image that is in the virtual world Isn't it? like for example for example Isn't it? You messaged him and didn't reply Came. If you don't get a reply then it's no big deal Pie. Couldn't talk in the real world We can talk in the virtual world, right? A fake world, a dream world. in the same manner The image formed here is a plane mirror How do I make that? she's always virtual It seems pretentious and not real. ok remember one thing Keep it and don't let it get into your mind Keep it aside. The RealReal's big brother Inverted Real's older brother Inverted. i.e Whatever image is real, do you know how? will it be? She will vomit. Vomit. how would it be Son? Vomit. Ok? and virtual virtual Who is virtual's elder brother son? of the virtual Big brother erect. Erect means straight. Erect means straight. Is it okay son? How will it be? Very straightforward. very nice. Isn't it? So Whenever the image becomes virtual, it will become straight. Whenever it becomes real it will cause vomiting. Ok? Now you tell yourself you stand in the mirror Go and see for yourself. is your image Is it becoming straight? if you are saying it directly yes? It is not working. Son, she is becoming simple. If it is not working out for you son, then make the same call Tantric. Ok? It is obvious. It must be becoming straight. Isn't it? How? Why Will it become straight? Because that is a virtual image. So how is the virtual image always created, son? It becomes erect. very nice. well your How is image formed in a plane mirror? Laterally Inverted. I just told you, I told you. Let's see further. What is the next point? Same size of the image. That is, the image which The size will be the same as the size of the object. You went and stood in front. so as much as Your height is the same as you see in the mirror It must be visible. Is this true? Tell me once quickly. Yes very nice. Isn't it? Very true. Everything is going well. see you next. Next point. the distance Between the image obtained from the mirror is same as the distance between the object From the Mirror. I am explaining to you son, I am not loading Take. Suppose you are looking at this mirror from the mirror. I I am standing here. This is a mirror. I stand here Am. Ok? So the image that will be formed in the mirror Behind it will also be built at the same distance as I was away from the mirror. Isn't it? I was here. There was so much distance. at the same distance My image will be created. Just saying this and nothing else not saying. Ok? So here are some points Were. Apart from this there is a point on which repeatedly Every time MCQ question is asked is the focal length of the plane mirror. Focal Length what happens? We will talk further. But just now You must always remember what the focal length is it occurs? It is infinite. son what it occurs? Infinite. So remember Focal The length of the plane mirror is infinite. i.e We can't count him out. Even to the Did we all understand the story? Quick chat Speak inside. Now let's move ahead PK Bhaiya. Smart PK bhaiya. Towards the spherical mirror. Is everything done till here? very nice, very nice. Dude, you look at that students who study the night before You get such good marks. Is No? So imagine if you did a little bit of studying If you do it with determination, then you will create history, brother. Don't underestimate your own potential. You Be the one who reads well the night before You get the marks. So friend, there is still time. How good marks can you get? Is No? Right. Come on brother. So with the same motivation Let's move forward together. Isn't it? and in a different manner We will move forward while understanding things. Come on. See There are two types of spherical mirrors. there is one Concave, one is convex. Bhaiya this is concave Who? hey son look hey son look See what a cave looks like? what was the cave like Is? Cave son, there is something like this. In the cave Who lives there? The bear lives. Have heard. So What is a cave like? the cave like this it occurs. So who's coming to Kev's what? Kev is coming. Kev right? if you carefully Who will you see then Kev? Kev is coming. Kew That means cave. So the concave mirror will be like this It will be like this. That is like a cave will be. What would be one side of it? Polished. It will be polished. Polished means there Pay lights cannot collide. Ok? And this which What will be the other side? These There will be a reflecting side. What will happen, son? Reflecting side. Ok? So this happened Concave Cave. What else? Convex. So Its exact opposite. What to do? Its like this Make it the opposite. Isn't it? and on the inside Polish it. What should you do, son? the inside Polish the side. very nice. so what is this Is? Convex. What is this? Who? Cave. Kew That means cave. It will look like a cave. very nice. ok sir. These are two types of mirrors They happen. Now here you will find some things There are some important terms that you should know Should be. Lots of important terms Are. pole, center of curvature, radius of Curvature. We will understand it one by one. Ok? I'll take you back to the diagram I will bring it. That will give you more clarity Son. Ok? This is your convex. These This is your concave. I hope this image please you It will be clear. This image is clearly visible to you She must be giving it. I hope I got a little I reduce the brightness. ok sir? So that it may help you. Now now absolutely It must be looking great. Come on come. Look carefully, son, look carefully. Poll What happens? Pole. what is a poll Brother? Poll Dance. No son, what is a poll? Poll It is this reflecting surface What is? Concave Mirror. The mid point of this its mid point is the pole, son It is called. Ok? of reflecting surface The mid point is called the pole. other than that Understand, son. if this was a reflecting surface Isn't it? So this is somehow the whole There is a small part of the circle. Isn't it? If If we imagine a complete circle If we imagine the whole circle then that The center of the circle will be a There is a center, it will be the center of Curvature. What will you tell him? will write C He has a C, right? and this will come to your center of Curvature. very nice. Very good son. Look ahead. If we pass a line, a a line which is connected by center of curvature and pole Will pass from. So what do you think about that line? Will you say it? I will say that line Principal Axis. this is that principal Your school is not there, son. who is this Is? Principal Axis. Ok? The next thing And the most important thing is center of curvature And the pole is its midpoint, the difference between these two which is the mid point i.e. the portion in the middle yes, what do we call it? Focus. or else Principal Focus Inside Many Books It is also written. Ok? we are talking focus Are. Ok? Now understand carefully. From here Where is the distance from and to here? Centre The distance between the curvature and the pole, I call it radius of curvature. Because the distance from the center to the circle is What happens? There is a radius. read it? Hey did you read it? Yes very nice. Radius of Curvature. and from focus to pole There is distance, what do I call this? I call this focal length. What do you say hmm son? Focal length. Ok? Focal length. I've got it? Very true. well now also Think for yourself, what was this? Mid point. These what was it? Mid point. so can i say Am? If I double the focal length That means I make the focal length two times So what will he be equal to? Radius of of the curvature. can I say this thing Am? Yes or no? Quickly, quickly. yes, very much Excellent. One thing is that friend, no matter how much you are Are the CBSE kids with them? The kids who study in CBSE are different from all others. They are different. They are unique. know why? The problem with them is that they don't know Hindi They don't know how to write nor speak English It comes. Isn't it? I would lag at both places Are. Either brother we should learn English well I would teach you both how to speak and write Hindi I am not able to come. Isn't it? Be Relatable Went. So did you understand? How did it happen? two times of Focal length. is equal to the radius of curvature Went. very nice. very nice. Good. Now this is the reflecting surface, if this I full length of the reflecting surface If I take it out then it will be called aperture. What Will it be called? Aperture. Don't worry. all You will see the definitions. these beans With whom does this thing happen? of convex mirror with. With whom? With convex mirror. convex mirror look something like this it occurs. This is your convex mirror. Ok? What happens from the inside? Look, it is polished like this. ok sir? Now What is? These are all the things. radius of Curvature. from here to here The distance is the radius of curvature. Here But the principal focus will come and from here on What will happen till here? Focal length. What will happen Son? Focal length. Ok? very nice. These We have completely understood the matter. I had fun. So now let's read the terms one by one Are. Do not take too much load. Come on. Look what is the pole? The pole is the center point of The Reflecting Surface. What is? The center point of the reflecting surface That will be called a pole. very nice. next. Centre What is off curvature? center of curvature what is it brother? the center of the sphere of we Mirrors Reflecting Surface Forms the Part. That means, it is a small mirror. For him If it were a complete surface, then its The midpoint would be its center what is it called? Yes, center of curvature. What is a good radius of curvature? Now! told. I just told you not to make the same mistake again. very nice. What is the principal axis? Straight line passing through pole and centre of curvature. The one who goes away after crying. next. Principal Focus. Look where the focus is Sometimes the principal focus is also written I write. There should be no confusion. Ok? What is? is the mid point. whose mid point Is? Speak speak speak speak speak. Yes. center of Curvature and Pole. very nice. Next Focal Length. What is focal length? I told you There is distance. Last is aperture. Aperture What happens? the diameter of the Reflecting Surface. That is, reflecting What will the length of the surface be called? They It is called your aperture. what is that called Is? Aperture. tell me quickly if this Did we understand all the definitions? it Did we understand all the definitions? I am a I drink water for a minute. Come on brother, even I've got it. So now quickly tell me what happens next. I have a question. define focal length of the Spherical Mirror. What is focal length? What is the distance from where to where? is the distance from the principal focus to the pole. Next how is it related to the radius of Curvature. so you know two times What will the focal length be equal to? radius of will be equal to the curvature. always remember this Keep. Ok? Tie a knot. Isn't it? Tie a knot. Ok? otherwise in paper If it comes then anything can happen. Ok? Yes. So that's why remember the knotism. Come on, let's play by our rules now. What are rules rules? Rules means something Such rules with the help of which we can now create images We will form a formation. Will do it further. some rules Let us understand it. Come on. Rule number one. Oho parallel to the principal axis will pass Through focus. Change it a little bit. will pass through focus and and appearers and Appears to pass through focus. That is, either Will it pass in real or else we will feel so that she will pass it. hey what happened? Now! I will explain it to you by looking at the diagram. you understand everything will come. You are either under so much load or you are under tension How do you get stressed, friend? your Your brother is standing with you and then you are tensed Do you take it? Come on. Look, this is concave. Kew Cave cave cave yes I will remember it now. So look concave if parallel to principal axis Any light ray comes in. Ok? Any point parallel to the principal axis When light ray comes, where does it always come from Will you do it, son? With focus. From where? With focus. In the concave. But what will happen in Convex? Look, son. convex which is a mirror The diverging mirror is convex. i.e That light comes near him and he drives it away Is. This is also like that. Ok? This too Focuses tend to diverge. Whereas What is Concave doing? Concave everyone It is mixing. While what is he doing? is diverging. So this is my Also called converging mirror. This we Also called diverging. Will read further. Now see if any light comes She will always move away from the convex. Will she go away? away. now it won't actually pass through focus but appear to Near. How does it appear? Look brother. When Real If I cannot find anyone in this world, where would I be? Do you get it? In the dream world. Very I have experience. Isn't it? Virtual World In. So track back, track, track do it. So look, it is close to focus i.e. concave or convex whenever the light is parallel then will it pass with focus or will it appear to Pass Through Focus. come on brother rule number one done Done done, there are four rules, son. Rule number two of this Opposite, if any light ray passes through the focus If you do this then it will automatically become parallel. Let's see. Come on. like a thing in a concave We do. These light rays come from focus See. I passed it with focus. out of focus and this hit the mirror. What will happen now? Now This will automatically become parallel, son. Parallel to what? Principal Axis Parallel. Well what about in convex? Look Light Ray, where was Light Ray going? Towards focus. where are you son? Towards. Actually it did not go into focus. Towards Focus. But he is a dirty man. Convex. These It diverges. So what did he do? The son threw it away right here. Bye Bye-bye. Goodbye. It's over. Ok? So It became parallel. Ok? So, this is yours What? Rule number two. annie re passing through the The principal focus will become parallel to the Principal Axis. Rule number three and the most Easy rule easiest rule. Look son, who is at the center He is off curvature, he is a goon. What is Son? Goon. where are my glasses? The goon one. Bring the goon's glasses brother. To become a goon it is necessary to wear glasses yes son. So the center of curvature says that Brother, if you go from me, you will come back from me will come. If you leave me, my son I will have to come back by the way. and you have no Option. So brother what is the center of curvature This is hooliganism. He might be from UP and Bihar. Isn't it? There is level in UP and Bihar. Ok? Yes. Let's see. so like the concave in the concave if you see anybody If the light ray passes through the center of curvature Is. She passed, she passed. collided. Now back it up You will have to come through this path. That means she has gone. Went I. The center of curvature speaks to me Will have to come back. this is the same thing with convex. this is in the convex light ray thi na ye towards center of The curvature was going. Now this is back in the same will turn into the path. It is very simple. I Hope This must have become clear. rule number rule number Four is even easier than that. If any light ray Prince, whatever pole you had, that pole If it hits at any angle then it will hit the same It will reflect at an angle. I will explain How. Look, suppose it hits the pole. One He must have created the angle. You would have made an angle Son. You must have made the angle, right? Between whom? This is the angle. now when this reflects If it does then it will reflect at the same angle. That means whatever its angle will be exactly the same. Ok? Whatever this angle will be, it will be the same. these beans This happens with your convex mirror. You can see in that also, a thing collided here made an angle and then came back at the same angle what did you do? It reflected. Is this thing Is this absolutely clear to us? quickly quickly. very nice. very nice. These Got it? Keep your energy level high, son. Energy Keep the levels very high. Isn't it? Come on come on brother. Move ahead. Now comes the most important thing Which is image formation. what son? Image Formation. Now we will do image formation. These It is 1101% certain that it will appear in the paper. don't later Speak. You leak the paper. I am telling Am. I am telling you. Ok? so now now Understanding Image Formation Step by Step I will do it. Bring us a character for that It will have to be The character is Candle ji. Is it Candle Ji? To us the candle Will have to call. So come on, some candle Come on brother. So first of all the object is not an object. Respect to the candle Speak with respect, son, not an object Mr Candle. now the candle is on infinity Are. Infinity means very far. oh ho ho. Is no bro? The candle is very far away from us. So when something is very far away, the light rays that are there are always Comes parallel. So you see for yourself if The candle is very far away, so its light Rays will come, how will they come, son? she will come Parallel. How will you come, son? she will come Parallel. Yes or no? Yes or no? and to you Do you know where parallel light rays collide? Are? Focus on. So where will the image be created? Focus Pay. What kind of image will be created? A small image will be created. A very small tingy-ding like image will be formed. Ok? So remember whenever you reach infinity if it happens then what would be the size of the image Is? Highly diminished. highly diminished That means very small. Ok? Now understand something Important thing. Understand a case in the mirror You. Whenever the image is on the left side of the mirror Made. where are you son? left left left Left. So what will the image always be like? Real It will be. And who is Real's elder brother? Son? Inverted. and whenever the image is right Where is it made? In the right. so how is the image will it be? It will be virtual. and the bigger one is virtual Brother erect. Ok? now where is the image here Is it made? On the left side. So remember that The image that will be created will become real. and of the real Who is the elder brother, son? It is inverted. to everyone I know it. Ok? This is the first case. after I will also tell you the trick to remember them. There is a trick on me, P's trick. now imagine do it. Now I have kept the candles Called a little closer. There is a lot on infinity She was far away. So now candle ji is beyond the sea She has arrived. Where? Beyond C means C K Back. What is C? Center of curvature beta. This C is the center of curvature. yours I don't have any friends. So what? Behind this Candle ji, come and what is there here son? She has stood up. Now look what now? now you See. Now you see, it will be fun. See. Now what Is? Put a light ray parallel. And whenever If the light ray goes parallel then you all will know Where will she pass that from? near focus will do it. Did you come or not? Everyone knows. Now what Do it son? the second light ray to the second light ray what do you do now? this is the center of It is curvature, send it through. Because the light Where does the ray go from the center of curvature does it come? Comes back on the same path. Isn't it? Imagine if a light ray hits you If it is sent to the center of curvature like this then it will be returned back also Where will it come from? same way back will come. Yes or no? Yes or no? Ok. So Where are these lines meeting? at this place so Where will the image be created? The reverse image will be formed and such The image will be created. well how is the image? it is real or is it virtual? Left side means real. How is the image? It is not very big. The candle was very big. this is the image Small Ok? So we can say that the image is Diminished. Diminished means small. Real and Inverted very good. case number two understood I'm gone son. This mirror case is important. Why? because this case is not same in lens will be. It repeats and repeats. so here I am I am explaining. Understand the matter carefully. I became angry. Ok? Came. See. Now it comes Third case and the most important one. Importent It is also written. What does the case say? case this tells me if I let the candle go and I called him closer and I selected the center of curvature I made the candle stand there. Now watch Son, put a light of ray in parallel Two. Where is the parallel ray of light from? does it? Everybody knows, son. Yes. Do you know No? Do you know it or not? Correct. now the second light Ray knows where to send it? you are not focus Send another light ray. Whenever you are someone Son do you send the thing to focus. Whenever anybody What happens if the light ray passes through the focus Is? It becomes parallel. Parallel. Missing you Went? very nice. very nice. so this It will collide and what will happen? these parallel It will happen and it will come, it will come and these will happen among themselves I will meet you here. So the image that It will be made somewhere in this direction. And Do you know exactly where the image will be made? Its Below Where? Right below this. where at Candle was there and the image was created under it Went. Yes. And tell me the best thing about this case Why is it important? the size of the image Whatever happens is the same. the image was real Is. It is inverted. just tata bye-be good Bye. End. Go ahead. come on. case number Four. Inside this we will place the candle closer I am calling you, son. So the candles came are here. Isn't it? Between C and F. Now we will do the same. What will you not do havan Son. What to do? I will cast a light ray and What to do? I have only one thing to do. Let's go brother. and the second light ray now where am I should I put it? Isn't it? where am I for the second light should I put it? Now this is something to think about. Think Son, hurry up. Where can I put it? Where Insert it son? If you want the second light ray then you You can pass the exam with this kind of focus also. Any It is not a problem. Isn't it? So now this What will happen? This will become parallel. and this coming together somewhere and somewhere a little further Do you want to make this diagram a little smoother? We will meet somewhere at this place, that is, this Where can I find it behind the center of curvature? behind the center of curvature so the image which If it is made then the image will be big, how will it be Enlarge means the image will become bigger and real It will be made inverted, right, and where is it being made? Where is Beyond C being built? I will write it here beyond C Ok brother, I understood four cases very well, further Now let us come to our fifth case What is there in the fifth case, son? Now I have I called Candle closer and I made him stand here on the focal point Is. What to do? you will do what you do Have been doing so all my life. Isn't it, son? We have So there is only one work to do. So brother one line parallel very nice. Where do I insert the second line? I will put it on the pole. At the same angle. Isn't it? remember there was a law like this and not at an angle If you put it on the pole, then it will be at the same angle What is this? It will reflect. if you If you can see then both these light rays are parallel Is. what is this? Parallel. what is parallel Do things ever match? Tell. Yes. Where Do you meet them? Infinite Pay. Infinite means Very far. So we can say that in this case The image will not form inside. Now this I Answer because of your latest NCERT I am speaking from. NCERT has been updated And some corrections have been made in that NCERT and this thing is clearly written in the correction That image is not formed inside this case. Inside Schools explains that Highly An enlarged image will be created. yes in infinity The image will be created Look at the NCERT table which clearly states What happened is that we don't know anything about the image I can tell you because actually the image I do not want to make it. Ok? So in NCERT It has been updated. I will tell you the syllabus I have been. Now let's come to case number six. To all important most important this is a mistake Don't do wrong with that either. What did I say? Mistake Don't do wrong with that either. Ok? what's in it Brother? Are? What is so special about this? Are? Isn't it? That one picture comes, right? who asked Didn't you look back? Isn't it? so in that What is so special? What is so special about this Is? This is special, it will come in the paper. Ok? Now Look son, I brought the candle closer. I have called you and the candle has come here are between P and F. Ok? PF's Came in the middle. What should I do now? the one who does I have come. First of all you are a light Post it from here. Isn't it? A light ray like this. Isn't it? Now many people will say that Bhaiya is one Light Ray what to do? put it parallel like this and He will pass it with such focus. is this Is the diagram correct? So this is what I believe The diagram is incorrect. Ok? Why? Because Brother, if the object is standing then the light ray is straight He will put it. So what should I do to cut the object and then light it Will she go away? is the object. what light will it pass through object? she won't do it. So Let's change the diagram a little bit here. Because of this it gets complicated. We What do you do? We are working in this direction like this Let's cast a light ray. Where? This In direction. and this is the direction This is the direction of the center of curvature. That means the light hits here. and the same path what does she do on this? It reflects. And like this it passes through the center of curvature. Ok? So its diagram is something like this Will come from. Now understand carefully. It collided and Pass it back through the center of curvature. Now these two light rays should go away Have been. That means they will never be found. so this Where do you look if you are in the real world If you cannot meet him then where can you meet him? Virtual In the world. So now we'll see that these two Light Rays goes somewhere in the virtual world We will create an image here. and images How will it be? Image created on the right side Is. So how will it be? Virtual and erect. And How will it be? highly enlarged The image will be there. Ok? These ray diagrams It is important and it is virtual and erect it occurs. Remember this also. same case How is your image created there? Virtual and erect. Do you understand this I? Tell me quickly in the chat. quickly tell from. Is it clear? very nice. Very Isn't it great? Yes. Yes. No one will write That ray diagram is cross, right? The Candle G The love story of. Right? No comments Will do it. No one will comment. better than this I remember a lot of people kept asking me Is that Bhaiya the opposite gender distraction It is happening. What to do? The boys ask me Yes, opposite gender distraction is happening. What to do? son put dp Take. The day your face was revealed to him There is no distraction after that anyway will be. There is no need for any message from the other side. Correct Is? You can put a DP. Come. Did you understand it? Read it silently. Look, there were six cases. I know your case in these six cases I have lost my mind. But now I'll give you I will show you. Ila magic. What is magic? See. Now, I will show you a magic trick, son. Counting Here comes one two's four. 4 2 that one No counting, look at the counting 1 2 3 4 You just keep counting, write one here what should i write it is one na accept this position infinity okay then write to okay then Write three on it, then write four, then this Write five on this and then write this counting on this So, everybody knows it. Now do this counting in reverse Take. Everyone knows how to count backwards. Here Start with it. one two three below it Four and below it, five. where is bhaiya six Went? Forget about Six for now. See What is this? This is PK trick. all re There is a trick to remember the diagram. Now look at what do you want to see? number one whenever Your object will be on one and the image will be on one It will be made. Object at infinity. where is the image Is it being made? See for yourself. Where is the forest? Focus on. Where is the forest? Focus on. Where will the image be created? Focus on. Number two. Whenever the object is your If the center of curvature is beyond then where will the image be will it be made? On number two. where is number two? Between C and F. Ok? When it will be on three So where is the image being created? Three pay. See for yourself. When there is four pay then where is the image being formed? Beyond Sea is being made. When there will be five pay That means if it is on focus then where will the image be formed? Five. Five means infinity. Infinity Pay. And the sixth case is a very different case. that is You will have to remember it. in the sixth which The image that is created is created on this side. Isn't it? Eyla Magic. So this is the trick that we By utilizing these you can remember such easy things. Let's take it. Ok? is it clear son? Correct Is? So look at your updated NCERT. This is a PDF. Now look at this carefully. here what i was telling you at f where But is the image created? It is made on infinity. And It is clearly written that the image would not be Formed. That means we are not even the nature of the image Can you tell me? And we're not even sure about the size of the image can you tell me because the image will not be created Actually. Infinite means we are very far away I can't even tell you. Ok? so this is updated It is NCERT so I am telling you. ok sir. Let's move ahead. Let's move ahead. come now has been a big importance means that much Not Important: The Uses of Concave Mirrors what are they? Questions arise on this too. Look brother what is a concave mirror? a type Converging Mirror of. What? Converting Joe That makes things bigger. Isn't it? Is No? Like the one that comes in Doraemon, Big light. Just like that, it makes things bigger Is. So this is how you remember Doraemon's Big light. Ok? Who has seen Doraemon? By the way? You must have seen it. By the way, I too have I have seen it in my childhood, friend. so you You must have seen it too. Ok? Look Concave The mirror magnifies things. So it's like shaving, beard etc. You would need something a little bigger in it This is your image. So this is why shaving mirrors Are the girls inside applying make-up? Are. Isn't it? If you are applying make up then do that too You need something a little bigger. then concave mirror when We need to magnify things, make them bigger It is useful when it has to be done. other than that Solar furnace variant. What is a solar furnace There is a device which is able to measure the sun's rays. Points all the light at one spot. Concentrates. so which one is there Is a mirror used? Remember which one? Concave Mirror. This is also important Headlight. So look at your cars There is a headlight, right? So what is that? The headlights of vehicles are also concave it occurs. Look, it is like a cave. It is like a concave mirror. Ok? So the bulb that is there in it, you know that bulb where does it happen? Suppose this is a bulb. Suppose this is a bulb. do you know where the bulb is it occurs? The bulb is situated near the focus. That means this bulb is exactly in focus It is close by. Where? right in focus The bulb is nearby. put it there goes. very close to the focus of this mirror The bulb is placed so that we can see things at a distance Could see the Ok? very nice. Very Excellent. Let us go. Oh brother which car was this? Which car is this? Wow. looking very nice It has been happening. ok sir. will answer the question. Megha Oh my God. Where is Megha going? Megha She is going to the dentist. ok sir. Megha visited a dentist in her clinic. She observed that a dentist was holding an Instrument fitted with a mirror. state the The nature of this mirror and reasons for its use in the Instrument used by dentist. Which ones What type of mirror will a dentist use? The dentist needs to look inside your teeth Brother. So he needs a bigger image. of large image Use concave mirror only for this It is done. The question is asking why? Why Concave Mirror? Because brother Concave Mirror magnifies the image of your teeth. So That dentist bhaiya will be able to see and tell will find it. There is a cavity in your tooth, son. Is No? well dentists all that You ask me to get it done. what do you say These people? Root canal. get a root canal done Canal. Isn't it? My once little worm It got stuck in my teeth. Went to the dentist. Get a root canal done. Root canal? I said hey Don't get a root canal done. Just do the filling. Is No? Let's go to the next question. a student uses a Concave Mirror to Burn a Paper by Focusing sunlight identify the position where the paper Must be placed. what are you saying? this is it Your Concave Mirror. Ok? and that brother I have taken a paper and on that paper, Wants to concentrate all the light. Well the sun is very far away. then light from the sun How are you, son? Parallel comes parallel. So tell me where can I find parallel light? Are? So it is obvious that it will be found on focus Are. So where should we keep that paper? Near the focus of that mirror. Where? that mirror near the focus of. and this is the correct answer It is going to happen. Ok? Let's go sir. Very Excellent. I understood even this much. All good. Let's see the next question at the top of your screen. Son, here it is tiding tiding tiding. Let us go. A Science teacher. Oho, I talked about PK bhaiya. Wow friend PK bhaiya come. placed a candle In front of concave mirror. Student observed the nature size and the position of The image by changing the position. Question Let's read. What type of image is formed When the object is placed at the center Of curvature? See what I did? I Candle G to Candle G to Concave Placed the mirror at different positions. first question that when I put the candle at the center of If I kept it on a curvature then where would the image be formed? Beans beans beans. It is made at the center of curvature Was. How was she made? It used to be real. Inverted It was made. very nice. what will be the The nature and size of the image when the candle is Placed between pole and focus? Last Case Whenever we place a point between the pole and focus When we place the object, the image that is formed It becomes virtual, it becomes erect and It becomes bigger, it becomes magnified. Let us go which type of mirror always forms a Virtual Image? Variant question son. Mark the star. Do you know which one is such Image? Which is the mirror that is virtual And it will create a diminished i.e. smaller image. Say Let me tell you Convex. because concave mirror What exists doesn't create a virtual image every time. He makes it in a single case. While we just now Read further which convex will be yours How will he always make a convex mirror? Will create a virtual image and a smaller image. next Why are concave mirrors used in torches? Where in the torch or headlights and why? Are they used? because what is their job It happens? Tell. What is their job? Their job is to magnify. Okay, that's great. All of these There were questions and these are all of yours There were answers. Let's ask one more question. Then Moving quickly towards the convex mirror Are. Tell me its answer. Come on brother who will do it got this question? It is not a very easy question I will tell you. This is a question of a good level. Question what did I say? We need to look at the data. These What is data? We didn't see a concave mirror I have used it. Who have you used it? Concave To the mirror. and means different concave mirrors Are. Isn't it? There are three different concave mirrors. One is A, one is B, one is C. Ok? So The focal length of a concave mirror is 20, the One is 15, one is 30. and we have objects are kept at different locations. Isn't it? Separately with all three mirrors. Now the question what am I saying? in which of the above cases will the mirror form a diminished Image? That is, in which of these cases Will your image always remain small? Now in this You don't have to do the calculations. You just have to I have to see it. Look, the focal length is 20 and Where is the object? Say 45 penny. i.e Where is the object placed? Say. well, if the focal length is 20, then the center of Where will the curvature be? center of curvature Its double. That means it will be at 40. Yes or no? Yes or no? Absolutely. That is, we have created an object is kept beyond center of curvature. Memory Do beyond center of curvature. Isn't it? This C It is also kept behind. So whenever we if we kept θ beside center of curvature then Tell me, how was the image created? very small image It was made. Isn't it? So that means in this case Your image in case number one She will be small, son. She will always be small. Let's go a lot Excellent. Let's move ahead. List Two Properties Of the image formed in case two. Case Two What kind of image is being formed inside? Let's see. Case The focal length of the toy is 15 and the object is We took 30 cm. It is kept on. Look Double Exactly double. That is, we have It is placed at the center of curvature. And whenever we used to place the object at the center of curvature Son, what would have happened? very nice. Beans The image was created. Same Size Real Inverted and What was the size? the image would be exactly the same Was. Okay, that's right. Last question. What is the nature and the size of the image formed Bye Mirror C? It is like a mirror which is very My son is special. know why? Its focal The length is 30 but we have placed the object at 20 It has been kept. That is, we have placed the object beid means between between f and p its The object is placed in the middle. Isn't it? Because how much is that? This is 30. But I kept it at 20 only. Look counting It starts from here, son. this zero It happens. So we have kept it at 20. While the focal Where was the length? 30 p.a. So how is the image will it be made? Special Case Virtual Erect You know the magnified ray diagram Is. This ray diagram is very important Son. Ok? Come on let's move ahead quickly From. Now let's talk about convex mirror. Convex mirror, I didn't ask for it in the paper I am leaving but I will still tell you. very easy Is. It is very simple. Dekho Convex Mirror There are only two cases of this. There are no six cases. Two it is just that. Very simple. The first case is either Candle ji, you are on infinity. Second case either at any point other than infinity Are. See if there are candles on infinity Yes. Assume it is very far away. so whenever from a distance Tell me what happens when the light comes on? What It happens? It appears to pass through focus. Where will the image be created? Focus on. how will it be? It will become small. The first one will be diminished. Point The size will be made. and whenever the image is on the right side If it becomes possible then remember the difference between virtual and virtual Big brother son et. what's the matter, what's the matter Is. The second case can be any distance anywhere The candle is either here or there It doesn't make any difference. What would you do? First Put light rate, send it far away and where will you get it from will he do it? Will pass with focus. very nice. Now apply another rule. Which rule will you apply? Who He also comes and goes at the same angle. Correct Is? So track it now. Virtual World Go in. So where is the image being created? here at It is being made. That is, if any finite If you keep the object at a distance then The image will always be formed between p and f. Where? Between p and f. how is the image Will you make it, son? It will become virtual, it will become erect And a smaller image will be created. how will it be? Small And This is what tells us that the convex A mirror will always create a smaller image. not big I can make it. Never never. will make it diminish, He will make it smaller. This is a small light. These Big There is no light brother. This is a small light. This is its work. ok sir? this table i Let me show you a table like this Which you can read later. and this one What is the comparison between? Concave and About convex which I have already told you It has been kept. Look, I know it now that I see You must be feeling like this brother so many How will things go? How will I remember it? Buddy Don't you have confidence? Have confidence in yourself friend. Isn't it? If If you want to do something in life then all things Will have to leave it. either you do all the things Leave it. As many as you want WhatsApp, Facebook, leave all this. either dreaming Leave it. You have the option. either that Either give up or stop dreaming. Decision It's yours. You will have to work hard. Come. What are the good uses of convex mirrors Of? So convex mirror is like this small light Like. That means it makes the image smaller. So its biggest use is your rare Inside View Mirrors. look in the car no, do you look in such a way from the side that behind Who is it? So do you know what's inside that mirror? It happens? inside the rear view mirror It is a convex mirror which gives you a faraway view Shows it. Gives a wider view. Isn't it? So First is its rear view. The next one is Security cameras. As much as your do you have security cameras or They wouldn't be there. If you went to a hotel, then not one If someone peeks like this then Have you seen that? Yes. So whoever it is, remember his name. I am not able to understand it. He who happens to be his What happens inside you? Convex Mirror It happens. what happens son? Convex There is a mirror. Is it clear? Quick Tell me quickly. very nice. Correct? So you read the uses of convex mirror also. Also read the uses of concave mirror. now coming are subcent. Sign conventions. what son? Sign conventions. This is very important. Come closer. This is a topic that Numericals are bound to come and if you If you learn it today then the lens will also have the same color. what will come? The beans will come. Look no matter what Be it a mirror or a lens. I don't care Would have fallen. What doesn't matter? I don't care Would have fallen. Be it a mirror or a lens. tell me today I have been. whatever is on the left It will always be negative. Whatever is on the right It will always be positive. whatever thing It must be up there, right? She will be positive. whatever The thing that is below will be negative. that's over. Tata bye-bye. Goodbye. This is what the sign is about. That's it. Look, let's understand some terms. U what It happens? U is the distance of the object. Isn't it? How far away is the object? Values such as I'll put my candle here Gave. Isn't it? So this is the distance from the pole What will this be called? This will be called U. Ok? What will you call it, son? It will be called U. Attention You can understand from this. It is important. Ok? V What happens? v is the image distance. From where? From the pole. So assume the image from the pole It is being made here. So this will be the distance This will become V. And there is one more thing called F. F What is? Everyone knows the focal length. now then I have read it so many times. Ok? So these three There are things. You should know this. V.U.F. sign convention in full, that's it Is. I told you. come quickly now Whose side are we on? Towards some formulas. Like there is a mirror formula. big cute little Is. He is like a tiny little kid. The mirror formula is That means 1 / v + 1 / u = 1 / f. whether Whether it is a concave mirror or a convex mirror, Whatever happens. Remember this. this mirror formula It will remain the same. Ok? besides that one more The thing is magnification. Now you will speak Brother, what is magnification? So look Don't take too much tension. Magnification What is? Read the definition. refers to the Ratio of the height of an image to the height of an object. That means there is a ratio. These What is? Ratio. We will denote this by a small m Let us represent you. what is its formula It happens? height of image divided by height of Object. that it. Isn't it? Height of the image and the height of the object. That magnification. It has another flower. It has another flower. There's another flower in the mirror's case. that Is -V / U. Remember minus comes. What Are you coming son? The minus comes. - V / U of this This is the second formula. Just understand this much. Ok? So what is magnification? ratio of the Height of image by height of the object. And Another formula is -v / U. What are V and U? Is? You know it. Ok? Now I I will move on to numerical. But before that you One thing has to be understood that magnetism tells What is? Suppose your magnification is up -3. What does it mean? whenever If the magnification value comes to minus then Remember your image is real and bigger than real brother who? Inverted. very nice. Good If now this is the sum of minus and positive signs The meaning is different. What does the minus sign mean? what happens son? What does the minus sign mean? What happens? If there is +3 here. of the minuses Meaning real inverted. and if it comes positive Magnetization means virtual. Virtual and Erect, the older brother of Virtual. Ok? Minus and positive mean real Virtual. Now the values next to it are Like there is three here. what does three mean Is? that the image that has been created is three times The size is. i.e. forget the positive and the negative Go. He only tells me virtual and erect Is. Isn't it? And Real Inverted tells us this. While these tell us the future values How big is the image that has been created. Good value If your magnification is 0.1 What does it mean? Minus means real Inverted. What does 0.1 mean? 0.1 of This means that the image is made smaller. When the magnification is less than one then Can you understand what the image is like? It is small. Correct Is? If you don't understand it yet then use numerical We will solve it. It will become clear in that. Come Let's quickly come to the numericals. See Son, solve it. What is the question? a student Conducts an Activity Using a Flask Of a height of 15 cm. And a concave mirror. Ok? So what has he done? She has a I took the flask and stood in front of the concave mirror I have kept it. Flask means you can assume anything Take. And the height of that class is given to us. That is, we are given the height of the object which is is 15 cm. Ok? Now tell me yourself Should I take this positive or negative? We always keep the object straight. Above We keep it. I mean, what will it be like? Positive. Now This is a game of positive and negative, daughter Sara. look he finds that the image formed is 45 cm In Height and Real. what did you say? Real. Whenever your image becomes real, it is real Who is the elder brother of? Upside down inverted. and when also the image will be upside down, so I will tell the height of image What should I say? Positive or negative? Say Negative. Why? Why? Why? Why? Why? Because the opposite image was formed. whatever Thing down negative which is ok up top. Us Do you want to tell me what will be the magnetism? now then There is nothing left in the question. height of Image Divided by Height of Object That Is -3. So will you get the answer, how much will you get? -3. Let us go very nice. Done. Such questions come up. Ahead coming. Let's look at another question. This is big This is an easy question. a student wants to Obtain an erect image using a concave Mirror. There is a concave mirror and it is erected An image has to be created. Whose brother was erect? Of the virtual. i.e. create a virtual image With the help of concave mirror. How can it be made? Where to place the object? we know The focal length of the mirror is 10 Cm. you know if I concave I keep the focus in the mirror between the pole and the Only then the image of the object becomes virtual. Yes or no? Do you know it or not? Known Is. And what is the focal length? 10 cm So If I move the object 10 cm. fewer I will keep it anywhere. Isn't it? 10 cm less than nine, eight, seven, any If yes, a virtual image will be created. So its The answer will be less than 10 cm. What will come Son? Less than 10 cm very nice. Very good son. This also became clear. ok sir. And move on to the question. next Question for ₹1 Crore on your screen. tiding tiding tiding here it is. Come on. 5 Cm. Tall object. Keep writing, son. First of all write down the givens. Isn't it? how much given Is? What is the height of the given object? See for yourself. 5 cm ok sir. 1 minute. So What is looking at my face? the question itself This should not be solved through. prashant bhaiya he is I will get it done. Okay, solve it yourself. Ambulatory He is looking at my face. Came. at a distance 10 cm From a convex mirror. Who What mirror is given? Convex. Now comes a The most important game. and you are the star Mark it and write it down in your notes too. Tell me one thing. Which mirror is this? Tell. Concave? Which mirror is this? Convex. Well, the focal length of the concave mirror is Where is the length? Does it happen on this side? It definitely happens. then its focal length will it be positive or negative? whatever thing That negative one is on the left side. But Where is the focal length of a convex? Memory Do it, I have read the diagram on this side. That is, its focal length will always be How will it be? It will be positive. and this is to understand The game. Always remember that concave The focal length of the mirror is negative. Whereas Its negative for convex its positive. Now let us come back to the question. We are given the height of the object. Us Distance is given of the object. Good Where is the object always kept? whether Any mirror. Whether it's a mirror or There should be another mirror. The object is always placed on the left Keep it on the side. Yes and no. Yes and no. Absolutely. So the distance to the object is, what will be the u? Negative. always in What will always be the any question? Negative. So how much is given? -10 cm Very Excellent. from a convex mirror of focal Length 15 cm. Well, convex mirror's What is focal length? I just told you fool Boy. ok fool i am speaking with love Am. Don't take that much load. Isn't it? Our It's something in between. How did you say fool? I kept on speaking. Ok? What do you have to tell us? We have to tell you the position. That is to tell us v Is. v Isn't it? The position of the image has to be specified. The nature of the image has to be described. I have to tell the size. See what has to be done? first thing v I will calculate it. How will you calculate v? I just told you friend. what are you talking about friend? I just told you. What did I just tell you? Now! I told you. Say. This formula. is this Does everyone remember the formula? very nice. Now You keep applying. Now there is basic math. 1 /v We have to remove it. what is u? -10 AA Went. Ok? And what is the value of f? very nice. transfer it here Two. So the value of 1/v will be 1/15 + 1/10. Now brother, does everyone know how to take LCM? Is? I don't know maths LCM. who is speaking Is it not known? hey brother stupid boy come back Come here friend. I will explain LCM to you. Come. Isn't it? This is how you take LCM. Memory Have you arrived? Did you remember? Who remembered you? Tell I have to teach how to take LCM. Something No. So the LCM comes out to be 30, right? take it like this Yes son LCM. Who do we see first Both will be divided. Then both of them keep dividing again and again until there is a forest It should reach there. Ok? So here comes 30 LCM. Now how many times is this divided by 30 It happens? so this will come to you and this will come If you get + 3 then your final answer will be 5/ 30 and if you solve this then this will come 1/6. What is this 1/6? Whose value is it? These is the value of 1 / v. The value of 1/v is 1/6. So what will be the value of v? Took Reverse Do it. what should I do? Reverse. 6 cm i.e We get an image of the object, which is the image We have got that which is 6 cm. Ok? Where is it made? 6 cm Pay The image has been created. very nice. now tell me We have nature. look whenever in question If asked, tell me your nature. For nature you Just need to remove the magnification. What? Magnification. what is magnification does it happen son? Say. -v / u v value You know it. The minus will come. This V is coming What will happen to you? 6 cm and what is U Yours? U What is your son? U is -10, U Yours is -10 cm. Now look from the minus The minus was cut off. So what has finally arrived? The value of magnification is 0.6. What is the value of magnification? Went? What does 0.6 positive mean by 0.6 positive? Is this happening? Positive is telling that the The image that has been created is virtual. 0.6 what are you telling me? The image is small. little one C is poor, right? It is small. Well, now One more thing has been asked in this. Size of the image. Tell me the height of the image. How will you get it out? You have taken out the magnification. Magnification is set to 0.6. And There used to be another formula for magnification These. What is the matter? and look at you The height of the object is already given Is. That means this is a given to us. How much is this? This is 5 cm. so put it away Here. just put this five here Do the multiplication. Has the answer come? There must be a multiplier. How much did it cost? 3 Cm. Did the image arrive? Image size It is small. Isn't it? It became a small light. Big The light could not be used. So this type of A lot of questions are coming in your paper There are. This is the whole game of sign convention Is. if you've got the game of sign conventions Did you take it son, then you will have fun in your life It will be lots of fun. What will happen, son? It was all fun. Ok? Come on. doing this Are. Come on brother. Tell me this question quickly. Who was able to solve this? See What is said in the question? n object 4 Cm. In Height. keep writing what jo jo given Is. Ok? image of the height of the The object given to us is 4 cm. will it be positive or negative? Positive. is above No? Yes. Is placed at 15 cm. in the Front of concave mirror. that is, the object's Distance is given to us. What will happen? Positive or negative? Say. Negative. because the object will be What will that always be? yes it would be negative Is. I have already told you this. Very true friend. What is the matter. very very Good. Let's see the next one. What's given next? The focal length of the concave mirror is 10 cm. now tell me concave concave concave its Focal length left side i.e. negative. Very Excellent. what did you say? at what distance From the mirror should a screen be placed. Now these are the questions on the screen No, I am not asking anything in this. this is asking Where do I place the screen to get an image? let's go. So you will keep the screen where it is But where the image will be created. Right? So we have to Have to take it out. What to remove? V Removal Is. Isn't it? What is there along with it? Us The height of the image also has to be found. Ok? So we have to figure out one more thing. height of the Image. Come on brother, it's the same question. As Previous Kara. The previous one was from Convex. These It is of concave. Don't do anything. Same Use the formula brother. What is the formula? Say. 1 / v + 1 / u = 1 / f , right? Now Look what we have been given? us v Have to take it out. well u have given it to us. How much Is? Minus. very nice. Good focal length We have also given this. That too negative. Big This is injustice brother. Now I'll take it here What will happen if I go? be positive Will go. Ok? So this will come to 1/15 - 1/10 Let's keep watching. LCM is LCM right? then you will take LCM So how much will it cost? LCM probably coming to 30 will be. To check. very nice. Ok? His What else have you got now? here comes two more Here it comes -3. Ok? you solve this If you do this then the value of 1/v will come to -1/ 30. What came? -1/30 and what is the value of v will it be? Reciprocal. Ok? then the value of v It will come to -30 cm. What does -30 mean? What does minus mean? that the image is on this side It is made. So how is the image? It is real. Correct Is? Now what are you asking in this? Its At the same time, he is asking us to tell his height. of the image. So look at you for this You will have to remove the magnification. Magnification is -v / u, right? then What is? What is -30 u? Look, it's -15, right? So I take the minus out and this is it -30 divided by -15 okay this is in The minus sign was deducted and the answer came out There is one minus left so the answer is -2 The value of magnification is 2-What do we need If you want to tell the image, if you want to tell the image, then be careful look at us son look carefully at the object ka height given hai kya given hai 4 cm See, the magnification has the same formula is the height of the image by height of the Now we are given the height of the object If it is there then it just needs to be multiplied. Isn't it? The magnification value came to -2. Just multiply it. then it will come How much is yours? -2 = Height of image by height Of object which is four. And this just If you multiply it, the answer will be -8 Cm. well what does minus mean? Vomit The image is. Isn't it? The image is reversed. What, man How smart are you to stay with me You have become smart. You are asking questions. What is the matter? Proud of you. proud of you Friends. Very good. So many such There are questions. To practice you do You can. I will ask you some questions The question is basically that I will give you homework also. I want to give it. That is this question. This You should practice yourself. this is your homework Is. Ok? You can also tell us in the comments. You can practice by pausing the video right now. You can. Come on, let's move ahead. Now we move forward Whose side will we move towards? refraction of light On the side. Ok? Such questions arise in the mirror There are different types. which I gave you You will see similar questions in the paper Will meet. Ok? Now we grow In refraction. But before that, remember my son. Keep your enthusiasm meter not down. Laying it high Buddy. know why? Because I want you I am telling you that you will do it. Do you know You have a lot of people in your life There's no one to tell you to do it I will take it friend. But I am with you. I to you I am telling you, you will do it. You will do it all. Ok? So keep giving your best. Ok? And I am with you in this. Let go. Refraction of Light. what is refraction Is? Bending of light occurs. what would have happened Is? Bending of Light. when the light turns It is, isn't it? basically the light doesn't bend but That's to tell you that the light is bending off What is that light called How does the light bend upon refraction? So look brother what happens to the light The speed is different, it is different in the air Just like light shines in different glasses in water If you change your medium then you change the medium The speed also changed The speed changed because of which The light bends a little, let's see come on so what happens to refraction phenomenon of bending of ray of light when It enters from one medium to another. When If it goes from one to the other, then brother it is medium It will change. What will happen if the medium changes? Say Say. The speed will change. If the speed changes then the light It will bend. Ok? the bending of light Ray during the refraction occurs because of Change in speed. the speed of light changes Is. Isn't it? Because of which it bends. Ok? We have understood this. Now Look at some important things, there are two types of them There are mediums. There is a medium What? Rarely medium. Rarely medium. and one more This is your denser medium. Denser ie. Denser means which has higher density. Who I am gaining strength. Isn't it? Yes. As far as the body I don't have a flex body, man. Butt my Where is the body, son? Isn't it? But this is me I can even lie to you. Do not know Be my body. Ok. Let's reread and Denser. Rare which is more powerful. Dens Denser which is more powerful. Rare that It is light. Now look son, whenever the light is on A light ray also came and hit here. Ok? Where did the rarer come from? Denser. So a normal Let's draw. what is this, son? Normal. You know what normal is Is? Perpendicular to the plane. perpendicular To the plane. Ok? So whenever from rarer When she comes to the dancer, do you know where to bend? will you do it? The light will bend toward normal. These which is normal, look at the light like this had to go. The light goes straight. straight like this Caste. But this light will bend Towards normal. It will bend towards the normal. Where? Towards normal. Ok? and its The opposite case occurs when, say, the above The medium one should be denser and this one should be rarer. Correct Is? Suppose this light came. Made this normal. Now if you know this light, it was like this straight but now whatever happens is far away from normal will go. It will go away after 1 minute of normal. It will go away from normal. away from the How will I remember normal bhaiya? Trick Why To be one Prashant send it. what is the trick does she speak? R D Sharma is a great sweetheart There is a book. You all must have studied it in Maths. RD Sharma ji likes normal. Isn't it? RD Sharma ji likes normal. This way You will remember that RD Sharma liked normal Is. what do you like? Normal. That means, whenever If light comes from rarer to denser then it will be normal It will bend towards. Now DRDR means Doctor. Doctors don't like normal people Is. Because if they are normal then the doctor will tell you Why would you come close? A little sick will be sick Only then will brother come. So the doctor finds it normal I don't like people at all. That means he is normal It will bend away. So the doctor finds it normal Don't like the lock. R D Sharma ji who is He likes normal lock. Let's go like this Let's remember it. Ok? So this thing you Will have to remember this. Let's move forward now On the side. We read further. Look at something I give you I will tell you the laws. There are basically two laws. What are the lodges? the laws of Refraction. As we have seen in reflection, Just like we studied, now we will study law. Law Number Forest. What does the first law say? The first law is He says about the incident. Incident Re. Now There are no reflected rays here. in The name of the rays is refracted. Riff Because refraction is taking place. Yes. Incident ray, refracted ray and normal all Lie at the same plane. the same as over there Incident Ray, Reflected Ray, Normal All three. Reflected here instead It comes refracted. just tata bye-be good Bye. The first law is simple. The first law is simple. Tell Quick. Tell me quickly. Incident Ray, Refracted ray and normal. interface of the to media at the point of incidence all alai At the same plane. i.e. where these three The plane that you will get will be the same plane will be. That's all for the three. First Statement. Second statement subsection. What is the second statement saying? This we Also called Snell's Law of Refraction. what do you say son? Snell. what do you say Are? Not that one Snell. That One Snail No. Yes. Isn't it? Snell's Law of Refraction. what does it say Is? Sign of the angle of incidence. Sign What happens? a trigonometry There is an identity. You may have already read I must have taken it. Do a chapter on trigonometry It happens within your class 10th only. Correct Is? If you haven't read it then consider it a sin Trigonometry is Identity and some other things Remember the values. like sin 0 The value is zero. The value of sin 30 It is 1/2. Isn't it? the value of sin 45 It is 1/2. Isn't it? other than that sin 90 What is the value of? which is sin 90 Whatever value there is, it is one. This is just you Just remember this much. Isn't it? If you did likewise You must have studied Trigonometry by now. Ok? Now understand what he is saying Snell's Law? that whenever a light comes on then a What will we say about the angle it will create? Angle of incidence. and when it refracts will also create an angle. We will call it angle Off refraction. Ok? So Snell's Law Ye speaks of sin of angle of incidence divide by sin of angle of refraction will always Riemann Constant. what are you saying? What are you speaking? that sini / sinr this always happens will be? will be constant. Its value is always It will be beans. Ok? its value is always the same It will be. That means you know the angle of incidence I know the angle of refraction. Their if I I will find the value of sin and their ratio If I do it then it will be constant. Same thing happens Second Law. Remember this statement, son. It is a statement. Ok? Clear even here? Now understand. Now brother, I understand this constant It is said that it will be constant. But this constant will what? What will be this constant? So its name is refractive index. Son Understand. I know what the topic is Isn't it a bit tough with refraction Is. Isn't it? Nor are children able to understand it. You should understand what I am saying. I am explaining to you Am. You just give me 10 minutes. to you You will understand in details. but if you Neha There was no reply to Rahul's message on chats So he sees it. if you do this son I don't guarantee that I will be able to explain it. So just focus for 10 minutes, exactly that I need that focus. Is that the one? Very detailed. Look at this ratio will be constant. and the constant that The value will be equal to what I will explain. But before that you need a diagram I am showing you. on this diagram this year Questions in your seniors' papers has come. Refraction through the glass slab. Refraction through the glass slab. Ok? Look, I was asked to make this diagram again and again. goes. Therefore, practice it. What is a glass slab? From glass Such a rectangular structure was made. Ok? Well, now the light has come. Assume this light I. The light came on. The light came on. It collided here. what is the light son? Rearer. Rarely is it? What is glass? Mighty. Glass and Denser. Ok? What did RD Sharma like? You liked it normal, right? Yes. So back to normal The light would go straight. but look at the normal light She bent towards the side. Now this case is special because because light travels twice in the glass slab It will do refraction. How? once upon a time here on and once while exiting when the light Will go out. Tata will say bye-bye. So Look, now this light was going, it was going, I was going, I was going. Now it hit back. Now this medium is denser. Outside is medium rarer. what to the doctor Didn't you like it? I like normal people were not there. So this is normal for normal Son. This is the complete opposite of normal It will go to the side. So this is the diagram This diagram is important. now over here Try to understand some things. Assume this This is the angle of incidence. this angle of There is refraction. Ok? angle of incidence will it be larger or the angle of refraction will be larger? Tell. Oh, you can see it yourself The light was supposed to go straight but it bent this way It's done. Now this angle has become smaller. then remember Keep in mind that angle of incidence is always equal To the angle of refraction. other than that here But look, suppose this is the angle of refraction Is. So this angle is r. this angle and this Angles are always equal, son. Why? I had studied about opposite angle in maths. Had read. I had read about opposite angles of parallel lines. Yes. So these angles will be equal. Now suppose this R and this will be the last angle, It is called angle of emergence or emergent Angle also speaks. and this is what ray is No, we call this emergent ray. Ok? We call this angle E. Now I have this Tell me what is this angle in comparison to this Will it be big or small? So you are looking at Look, the light has gone away. this angle is bigger Went. So write here also that which will be E E will also be bigger than R. Ok? Ok? Now I understand this diagram so much. here at You will have to understand some things. Imagine If this glass slab does not come then do this the light goes straight straight straight straight It remains. for example if your If you don't have a mobile phone in your life then you Like you used to be a topper in your childhood. Today You would have been a topper too. But in your life Something went wrong. Mobile phone, internet Came. Because of that you changed your directions I changed the . Is the roast done? look at that same In this way, if you assume that it does not come here the glass slab the light goes straight going straight going straight going okay okay But where is the light going now? It's going here. okay so emergent re emergent re this What is Emergent Ray Emergent Ray and This is the distance between the incident rays This is the parallel distance which we call What does lateral displacement mean? Beta lateral displacement what is lateral displacement parallel distance between Incident ray and emergent ray is called Lateral displacement. There were so many things that Here's what you need to know. Ok? Definitions are important, especially whose? of lateral displacement. Emergent Ray Is parallel to the incident ray with a Perpendicular distance. what do you say Perpendicular distance? Ok? Memory will it remain? Tell me quickly. Tell me quickly. Very Excellent. I've got it? perfect. Let us go. Even That all things became clear. give it here Bar refraction is taking place. how are you Used to be? Now you can tell yourself. Now back come from back from back. do you remember me So I said sin of angle of incidence Divided by the sine of the angle of refraction is Always constant. the value of that constant what is it brother? The value of that constant is Equal to what? The refractive index of Equal. Now what good is this, brother? One I don't understand things. hitting with the second throw yes. I said friend again the same thing y2 Fear Prashant Bhaiya is in my heart. See First of all we know the refractive index This is how it is written. and some books It is also written with u like this inside. Ok? what is this? This is ability. this power Is. You will fight with me. So maybe I I may beat some people, I may not beat some others. Can I beat it? So that is my strength. in the same manner The strength of a medium is given by the refractive index That is how much he will be able to bend the light. Ok? So one thing you should keep in your notes Note down that the refractive index Is directly proportional to bending. That is, the more the medium The refractive index will be the same It will bend more light. Ok? End secondly reflexive index is also Directly proportional to density. i.e The medium which will have higher density, this will automatically be denser Isn't it what it is? Refactoring Index Vo It will be more. Ok? the density is higher High refractive index and bending too More. now this is an important thing it is inversely proportional to the speed of light. That means, son, understand that if any medium whose refractive index is higher then The light in it is very nervous She will go away stopping intermittently The speed will decrease while someone like this medium which is the poor rarer medium whose If the refractive index is low, then the light in it how will it go from quick to fast so that's why remember it is inversely proportional variant let's go let's go yes it is there then What is the refractive index i I told you is it a measure of how much light is bent how many lights can a medium be bent could let's What is the formula? Refractive of the index? if you have any medium We have to find the refractive index of . I Let me tell you what the formula is. The formula is There are C/V. C / V What is this? C is speed Of Light in Air. that you know Already 3 * 10 raised to power 8 right? I told you in the beginning. And what is V? Speed of light in that medium. That is, if I need refractive index of any medium What should I do if I want to remove the index? Speed of Light Divided by Speed of Light In that medium. of light in that medium What is speed? With this formula I can Also find the refractive index of the medium I can. For example, consider the speed of There is so much light in the glass. so tell What will be the refractive index? Formulas Put it in. Put it in the flower. So What will the refractive index be? 3 * 10 raised to the power of 8 / 2 * 10 raised to the power of 8. So this will be cut. This will come to 1.5. Ok? Yes. It is cut just like yours, son was also cut. Oh sorry. Let's go, right? 1.5 Refractive index has arrived. Let's go a lot Correct. Very true. Did you understand this? any of the The refractive index of the medium is You can calculate it. Now such a topic comes which confuses the children a lot Are. But I am saying more questions than this He will not come. There should be no confusion. Topic What is? Relative refractive index. I will ask you questions right now, son. accept accept Here's the medium one. Isn't it? There is no air Medium one. ok remember one thing about air The refractive index is always There is a forest. What happens? There is a forest. Ok? The refractive index of air is one It happens. Here's the medium one. Ok? Here's Medium and here's Medium two. Ok? There are two mediums. Both The refractive indices are different. Now the value Let me ask you a question Refractive index of medium to with Respect to what is this son? w.r.t. what Is? Are? What is this? with respect to With respect to the medium one. so his What will be the formula? telling the formula Am. Put down the one whom you respect We give it. That means with respect to whom You are giving respect, who are you giving respect to? Medium one with respect to it below Put it in. That means its formula will be n2 / n1 means if someone tells you Medium Two with respect to the medium one who you are respecting him put him down flowery In. i.e. refractive index of medium to divide by the refractive index of Medium one. This is its directly formula It comes readymade. Now there is another formula. Do you remember? Do you remember? Okay, let's write this another way. n21 n21 how? n21. Ok? what about n21 it means? What does n21 mean? that is it Beans. n2 / n1 this is what it means son Keep the beans. Now look, do you remember that? which has higher refractive index Speed of light low. i.e. refractive The index is inversely proportional to the Speed of light. You might remember. So this formula There is another formula for n2 / n1 which is What is its opposite i.e. v1 / v2? Speed of light in medium one divided by speed of light in this medium i did do it? Reciprocal. why did you do it? Because the light and reciprocal refractive index. so this You should also remember the formulas Are. Questions arise on this. I will show you now Now. Ok? Ok? what did you say? whose Respect him, put him down. As Refractive should be called in question Index of Medium One with Respect to Two So what will you write? n1 / n2 is n1 / n2 right? And the reverse in speed. Come on come on that's great. Let us see some of its questions. Clarity I will get it. Come on. Let's see the question. You will get clarity. Come on brother, let's ask this question Solve it quickly. Come on brother, who will give this to you? were you able to solve it? The question is easy. See, The refractive index of the water is 1.33. That means we have to calculate the refractive index of water given which is 1.33. what are you saying? If the speed of light in air is this find The Speed of Light in Water. Look at the formula You know it. of refractive index The formula used to be c/v, I remembered the speed of light in air divided by the speed of light In that medium. So we need water The refractive index given is 1.33. Us The speed of light is given this. remove us What is? We need velocity i.e. speed of We have to bring out the light in that medium. So what should I do? I will send it here. This I will send it here. So you do the calculation. Isn't it? The country is in your hands, friends. Correct Is? You do the calculation. this is yours The answer will come. Try this. Calculus Please do the calculation, friend. Come on come. next Let's see the question. next question. The Absolute Refactoring index. Absolute Refractive index means nothing. You Think of it like this, the refractive index is Is. Ok? of water and glass r 4 / 3 End 3/2. i.e. refractive index of water Is 4/3. The refractive index of glass is 3/2. Ok? now what do you say in the question Used to be? With the speed of light in glass. We are given the speed of light inside the glass Is. okay brother? Let's see the question. The Speed of light in water will be in water What will be the speed of light? understand. Think Think. ok let's read the second part First. The Reflective Index of Glass With Respect to water. can i tell you yes? Whomever you respect, throw it down. Ok? So let me write this down. Refractive index of glass divided by refractive index Index of Water. also know of good glass Yes, I know about water also. so values put Let's do it once. Come on brother, let's get to the values Let's put it in. 3/2 Divide by Divide Bye 4 / 3 ok sir? what is the answer coming Son? Is the answer coming? then it will come Yours 9 / 8. Ok? so for the second part We found the answer. 9 / 8 First part. Now look carefully. You know it. you know this term carefully See. I want you to look at this carefully, son. What I'm going to do now is a miracle will be. See if I can do this reciprocally And I can write something like this. What Tell anyone about any objection or problem Give? How did it happen? How did it happen? Brother this How did the question come up? Look brother, what did I do? Velocity is reciprocal. Ok? So I can write like this. Put this on top. Put it down. Ok? now look at you Its value is also given. Its value also It is given. And see what is given? of glass Velocity is given inside as well. what to take out Is? This has to be taken out. So now you don't Can you throw me out, fools? just put it here Take it in multiply. just tata bye-b End. I went goodbye. Ok? such an easy question Was. Isn't it? It was such an easy question. Ok? Yes. Come on brother, let's move on to the next question. Let us go Let's look at the next question. Well you know, one of mine I believe that every girl needs a lot of hard work in her life You should definitely make friendship with at least one boy Because you can learn everything there That's how to live in a makeshift manner. Is No? How to maintain friendship in life Is. And boys you will also get more from girls You should make friends. Now you need reason I don't need a little. you know it so You should do it. Ok? you have a reason Not required. Okay, do it if you can. I don’t trust you either. See What is? Water is speaking in the question has a refractive index of 1.33 and Alcohol has a refractive index of 1.36 Which of the two mediums is optically denser? Who is more powerful? whose refractive The higher the index, the more powerful it is. Very Excellent. So who has more? Obviously C The thing is. 1.36 means alcohol. Alcohol Mr. Shri Honey Paaji had said this before leaving. Four bottles Board work is my daily routine. Ok? So The refractive index of alcohol is The more it is the more optically denser it is Is. Ok? draw a red diagram show the pathway of the right light passing through water to alcohol. Look brother this is water, this is alcohol. Now Look, son, the water which is refractive The index is low. That means this is rarer and this Denser. Now you yourself tell RD Sharma what did you like? Tell this to brother RD Sharma what did you like? hey bhaiya i liked it normal No? So some diagrams will be made like this Will go. The last part states the relation. Oh yes, you are not able to state the relationship yes brother. state the relationship between the Angle of incidence and angle of refraction. Variant. Look, let's say here's the angle i And here's the angle r. the relationship between them Tell. You know a formula sini / sinr = refractive index yes yes good How will you write refractive index here where are you i light air i air so I am saying sorry where did the alcohol come from I? It has come from water right? If we know about it If you want to write refractive index then use the formula what will be the formula, it will be reflective Index of Alcohol Divided by Refractive index of water. Ok? They What will be their net net? Net Refractive There will be an index. Ok? In Which I Divide Bye from where it came from? In Which I Divide By From which it came. I told you, right? yes let's go. So just write Two brothers. The value of refractive index will she come? What about alcohol? have alcohol 1.36 divided by 1.33. So this is the relation This is a relationship, this is what is called a relationship. So You have to write this in the question Was. ok sir? So this is what this relationship is called Is. Isn't it? This relationship is not called anything. This is what it is called. Ok? Let me know Slightly higher in refractive index Sometimes there is a problem below. a little If you practice you will have a son. Now Let's increase. bro you looking smart Your PK bhaiya is my friend. yes today it is The clothes are also green. So son, I am I am a green flag. what am I? Green flag. Does it speak in your language, Green? Flag, Red Flag, Purple Flag, Orange Flags, all flags. I am green brother. Come on, let's read the lens now. There are two lenses too of sorts. Concave convex. Concave Convex. Concave Convex. Now look at the son concave and What will convex lenses look like? So A convex lens is something like this looks like that. Is it okay son? some of this by type. And the concave lens is something This is how it looks. That means, what we have you done it? To make a convex lens We have combined two convex mirrors. Now if you look carefully this is also convex It was a mirror. This was also a convex mirror. among themselves I combined the two. Ok? Similar We joined these two concave mirrors together Gave. Ok? So a concave a convex. Now here is the opposite. The lenses are exactly Opposite of the mirror. what are you saying brother? He said something very important in English. See Understanding. Those which were mirroring are not lenses do. i.e. what is concave mirror in mirror used to do it? Cave. What did the cave do? used to convert light into one direction In. Isn't it? Remember or not? Converting? Yes. But here, this convex will be there What will Convex be like? Converging lens. That means it will converge the light. While Joe What will he do if he is concave? that light will diverge. will send it away. so this Converging lenses and divergent opposites. The opposite, completely opposite. as in the mirror The lens opposite to it. Let's go, right? now over here Some bad things also happen. like we had there But I had read it. a few things changed here They go away. I will explain you with diagram I will give it. I will explain you with diagram I will give it. Look at this diagram, son. Let's see. The first thing that would be the center It is a lens, we call it O. O! That means, oh no, I saw that magic picture. Oh Oh Oh oh that one oh no. This means optical Center. Similarly there is an optical centre also. Is it ok brother? now remember this here here There are two different focuses. a focus then Right side, one focus left side. Ok? Its focus is in two places. The focus is in two places. Just like your friends also have two places The focus remains. By the way its focus is also in two places Is. One, here we call it F1. And One, here we call it F2. What Do you say anything? F2. Now in this diagram, a There is a mistake. what's the mistake? what is this C1 and C2 Is? Bhaiya this must be the center of curvature right We had it in the mirror. No no, remember it. Remember there is no C in the lens, There is no center of curvature. In the lens What happens? The lens has 2F1 and 2F2 means the same. Only the name is different. So the paper Never write C in my answer otherwise it will appear in the paper It will become your C, son. So, therefore C I will not write. 2F1 2F2 2F1 2F2 2F12f2 very nice. Great friend. what's the matter Is. Isn't it? It means that from here to The distance till here and from here to here Till here the distance will be equal for both Will be. Ok? Ok? and now this is you too Can you tell me what F1 will be like? TWICE. Look what does 2F1 mean? that this It became double. What happened? This is double of F1 Went. very nice. even understand this thing I? well, there's a line that's optical Will pass from the centre. his name is also same will be. Principal Axis. What will happen? Principal Axis. very nice. Ok? So Now look at all the definitions one by one. By the way, definition is not asked in the paper but Yet the first principal axis is a Imaginary straight line told aperture There is also a term here called aperture, such as What was the aperture of the mirror? Reflecting length similar to what it is here is the diameter of a circular Outline means the circular outline SI lens what is this speak speak speak speak Which lens is convex and which is circular The outline is the outline, isn't it, its diameter what is he called his own, that is called Aperture. Ok? Optical center address. There's nothing called center of curvature here. It doesn't happen. Remember nothing happens. Radius of curvature doesn't matter either. Correct Is? The principal focuses are F1 and 2F1. F2 and 2F2 are two each here, son. There are two here. Let's move on. Now some important thing some important thing Which is what I have to tell you. Like we mirrored I had read the rules. There are rules here too. Yes, there are those here too. But there are fewer rules here. Yes and there are easy rules. and its jo The diagram is the simplest one. I am literally I am telling you. I am telling you from my heart. To all It's simple. Look, rule number one. Rule Number One what does he say? The same thing. look if you thought you were a mirror in the lens 1% There will be no problem. See 1%. if anyone If the thing is parallel then from where will it pass? Bol Bol Bol Bol, she will pass it with focus. Now Understand it here. Which lens is this? it Which lens is it? Converging lens. What is this will he do it? Will converge the light. Assume one The light came from here. it was a line between and beyond this line things start to bend It seems so. So it will bend the light like this This way. Ok? So what will he do? Converge Will do it. Ok? If any light ray is parallel Hogi it will pass through focus. well this thing If we look at it with the help of this lens. These Which lens is it? Concave. speak repeatedly walk so that inside your memory Let's practice. Now see what it does If this happens, he sends me away. These There is a diverging lens. Ok? so actually I will not pass it with focus. but which Where are the things that we cannot find in real Do you get it? In the virtual world. so come on brother virtual virtual virtual virtual Virtually awesome. So in f1 in f1 What will happen if I go there? Whenever the light is parallel Will pass with focus. It's the same thing. next Let's see. Come on next. Look at rule number two. Very simple. It has its opposite. if ever If the light ray passes through the focus then it will say focus Go parallel. what happen look parallel ting ding ding ding ding ding ding ding ok there is that cartoon sir ninja hammer ding ding ding ding ding ding ding ding something like this used to happen ding ding ding ding ding ding yes just like that ding ding ding ding ding ding ding ding ding now what will happen the light will become very parallel Good son, this is not a mirror that reflects the light This is the lens so that the light passes through the lens It does okay, let's see further here now look the light is going towards focus What will happen if it is going that way? Parallel. What Will it happen son? Parallel. What will happen? Parallel. very nice. This is also a number. These I understood it too. Rule number two is simple. Rule Number The third and last rule is the easiest. from here Who is the goon? Who is the goon here? from here Optical center is a goon. Optical Center He says whoever goes with me will go straight. It will not turn. Whoever goes to me will go straight Will go. Bhaiya, whatever I want to know, it is from me Turning is not turning. Go straight ahead. No Bending. No bending. So whenever the light will pass from the optical center, there will be Zero bending. The light will pass straight ahead. Ok? The light will pass straight ahead. Similarity: Even if there is another lens, It is a concave lens, the light passes straight through. Now You must think why this zero bending has occurred Is it happening? I am telling you a concept Son. Remember this. Remember this. then the light bends I don't do it. There are two cases. and these two cases Take a note of it. There are two cases. When your angle of incidence when your angle I how much will be? It will be zero. When the angle of incidence It will be zero. and the second case would be asked this It is in MCQ. Ok? Second case. What is the second case? When both mediums are same Light is going from one medium to another Is. When the reflective properties of both mediums The index should be the same. what's up? Be the beans. Isn't it? If we assume that light flows from water into water If it is going then it will not bend the light. The refractive index of both is the same. So These are the two cases when the light does not bend I would do it. Now this is your homework. tell me this What is happening in these optical centers? of two? that the light is going straight It has been happening. Ok? it is not asked in the paper But search for extra knowledge. Let us go What is flying today brother? what is flying is it friend? Have you come to meet me? have you come to meet me What.. with me? Let's see. Now understand, son. Come on image formation of convex lens. Brother there are six cases. like six in a concave There were cases. There are same six cases here also. as you remember there we Six different ray diagrams were made. in which did you make it? In the concave. There was a shock here. Shuk Shuk means reverse. So there are six here too. There will be cases but they will be of convex. See case number one object candle g very It is far away. Oho here you go brother Candle ji come again. The candle is very far away. Absolutely infinite. So whenever something goes away, son How does the light come? How does the light come? Tell. Tell me brother parallel. and whenever the light What will happen if parallel comes? Where Tell me will I get it? You will find them in your focus. Ok? So where will the image be created? On F2. Focus Principal focus F2. cute little one Munna F2. Ok? How will the image be created, son? Hey, what happened brother? How will the image be made Son? Tell me this. How will the image be made? Tell. ok now i told you about the lens and The mirror is opposite. What used to happen in the mirror? Whenever the image was formed on the left side What used to happen? Real Inverted. Whenever the right I used to make virtual erect. here at It is opposite. exactly the opposite that whenever the image What will the image be like if it is made on the right side? Real plus Real's big brother inverted. And Whenever it is formed on the left side then the virtual and Erect, the older brother of Virtual. Ok? Image Where is it being made? On F2. on the right side so How will it be? Real Inverted. and the image will be Point sized. How will it be? The very small Highley Diminest. Tinny Munni. all case same It will be like a concave mirror. Jo Jo Concave Mirror, whoever remembers this, needs to remember this There is no need. and that's a very lovely thing that if you get a mirror then this I won't miss you. Next Beyd 2F1 Like what used to happen there? beid see here But what will happen? beyond 2f1 come on candle yes friend. where are you going? goes without being told yes me. Come on. Here brother, make a light ray. ding ding ding ding ding ding ding ding ding ding ding ding ding and where is that Will it collide? will go from here. very nice. Now You know their ray diagram is very simple. Always throw a light parallel and out of focus Get it passed. The second light ray is always called optical Throw it in the center. Because the optical center Nothing can ever turn back from that. Ok? then the second light ray is drawn from such an optical centre what should you do like this? Throw it like this. That is, I have what did you do? The second light ray can be seen as an optical Thrown from the center. So these two lights are Where can I go to get it? So you are getting this are between F2 and 2F2. Where? F2 and In the middle of 2F2. if you remember the mirror What used to happen in it? Between? Speak Speak Speak bolo bolo bolo f&c f&c You would have been getting a lot between F and C Good son. What's the matter, friend? what's the matter Is. Let us go. Isn't it? So it will be made like that. Image How will it be brother? It's beans. Image Small It will be made, it will become real, it will become inverted, upside down It will be made. Well, this is case number two. now coming Quickly, case number three. case number What is three? I called a candle here to yes. Remember what used to happen on C? Sea Pay What used to happen? The image was formed at the same place and It was made of same size. look here now Son. ding ding ding ding ding ding ding Ding ding ding. Ok? and and here's the one Cast the light ray. A light ray can be seen from here Put it. where these go to the point If you get it then that point will be for 2F2 It will be below. 2F1 was the pay object. Image made On 2F2. It will be of same size. How will it be? At once Beans. Same size real inverted. Everything Beans Is. There is nothing new. Bus Ray Diagram They are a little different. Ray diagrams are a little different Are. ok sir. Let's see the next one. Object Between 2F1 and F1 is an object like this Where do we place the object when? Candle ji is here. Remember when C and If the object was in the middle of F then the image Where was it made? It's a beady, right? Similar Here we will try making it Bhai Ding ding ding ding ding ding ding ding ding Ding. Ok? And that is how we do it We will do it like this. So the lights which go together You will find her here or there. i.e The Byrd 2F2 is being built behind the 2F2. Isn't it? How will the image be made? It will become big. Large Image It will be made. Isn't it? A very large image will be created. It will become real, it will become inverted. Brother this is it No? Yes. What's the matter, friend? all to you I remember the cases. Very good son. Once Well done. Come on. Give it to me like this also. I I am also working hard. standing so late Am. I've been standing in front of you like this for one and a half hour I am standing, friend. Are? Tell me friend. a little Well done. I too deserve it Son. Let's go next. The same case. Now accept it I brought Candle ji to F1 and made him stand there has given it. What used to happen in the mirror? Infinity. Now let's see what happens here will be? ding ding ding ding ding ding Ding. Look brother both are light rays It is parallel. If light rays are parallel then where will they be Will you meet me? Infinite. Isn't it? you know what son Even the light rays of your life It is infinite. Isn't it? in your life When will you get it? Infinite. Ok? Then like this the light ray here is also infinite I will meet you at What image will be formed? Image Will Knot form. tell according to new NCERT I am here, son. these kids don't do anything wrong Will come. NCERT has been updated. And It is said in it that whenever I kept my focus If the object goes to infinity then the image It is made. then the image will be real or virtual will be, will be big, will be small, about her We can't even speak. We about him I can't even tell you. Ok? very nice. It will be made on infinity. Very true. I've got it? Isn't it? Come on and the last case and the most Mark the important cases as stars, son. The last case was when I saw Candle ji Optical Centre what is this son? Optical It is placed between center and F1. Now See what happens here? This is very important Son. look first send the light ray ding ding ding ding and ding ding ding Do it like this. what is this brother ding ding Ding? Let us go. And the second light ray is like this. Now Look, can I find these two lights anywhere? Will not be available. I am going far away, son. So where will I meet you? in the virtual world I will meet you brother. Yes. yes so such virtual You can go anywhere in the world and find it here right then where will the image be created tell me image left on the side and whenever something is on the left i.e. The image will become a virtual erect plus large or then you can write highly enlarged Okay, did you understand this sixth case quickly? Tell me quickly, did you understand this sixth case? Variant i.e. Concave Mirror and Convex lenses are the same if you understand one When you went, you understood the other thing too, right? okay and its red diagram son that one is special hey brother what happened to him The ray diagram is particularly very It is very easy. Right? Come on, this is your whole There is a complete summary of it. look at this summary and tell me Is there any doubt in this? Come on brother its very easy Was. Did everyone understand? It is very easy. And Everyone must have understood the diagrams also. Memory What is the image in the last case? Is it possible? It becomes enlarged. make a bigger image Is. And what is the image like? would have been virtual Is. Virtual's older brother is erect. Let us go. what are the uses of good convex lenses Is? The first thing is this converging lens Is. We can use converging lenses in one way and You can say that this is also like a big light Will Work. That is, they magnify things Will do it. what will he do? Magnify. So its there are uses, the first one is that Magnifying glass. Do you see that? As such Have you seen it? through a magnifying glass Let's see. Yes. so the magnifying glass Do you need this magnifying glass, son? You may get the answer even when you get your number I want to see it. The number is so low that it is visible, brother Can't find it. But you're reading from me Then the numbers will come. Ok? So Inside the Magnifying Glass you will need: Is. The next thing is correcting hypermetropia. You will read this in the next chapter. Human Eye When you read you will read it. forget it right now Go. the next thing used in microscope and Telescope. remember as much as there are microscopes and telescopes because The thing has to be magnified in the microscope. So In that also your same lens is convex lens. Which one? convex lens, which It works like a magnifying glass. Same It is used. ok sir. is this Did you understand the thing? Okay, that's right. Ahead Let's see. Now let's talk about concave lenses of. Whose son? Of concave lens. Now remember Do convex mirror how many cases were there in it? There were two cases. Which are the two cases of concave lens Case? Beans infinity any or it will be infinity Or it will happen at any distance. if the value Take my sweet candle It is on infinity. my sweet love If the candle is at infinity then light it How will she come? Son? Light from far away will come. and you know it's not light throws it away like this. what does it do It throws away the light. it will Appearers to meet at focus. That is, if I If I track it then where will I find it? This object will be created on focus. Is No? So the image that will be formed will be on focus. The big one will become small. How are things going? Virtual. Virtual's elder brother Bol Bol Bol Bol Bol Lyrics. Hey man, erect. very nice. What The thing is. Isn't it? Assume the second case Your object can be at any distance It is at a finite distance. let's assume We have our object here. Ok? So now Look, send a light ray like this. So You know he will go away like this. Yes or not? Everyone knows. very nice. Good The other light ray doesn't have the same pole Son. Optical center. from optical center Send it straight like this. Someone from optical center It does not turn at all. Optical Center To Gunda Is. Now backtrack this. Back track do it. then you will see that the image is here It will be made. Ok? Which point is this? Pole. There is no pole sorry optical center and F1 so That is, where will the image be created? Between F1 and O In. What will the image be like? It will be small. is small No? So remember this is your lens. Concave lens: This will always make the image smaller. Magnify can never create a larger image. It will make it smaller, it will make it virtual, it will make it erect will you make it? Did we understand this, son? Quick Tell. Tell me quickly. Isn't it? Tell me quickly. Okay, tell me one correct thing. like this with you How many times has it happened that something means something to you There must be such friends who when Your results are good. Isn't it? Then After that, they go home. Isn't it? and home I go there and say mummy that's mine I got 20 marks out of 50. so his mom She scolds me, how come so few have come? So They say mummy he is the same as Rahul Have come. ok and how many for the class topper did you come? 25 highest marks of the class topper It is only 25, mummy, 25 is the highest and that Your best friend, his mother, he failed It's done and you may have got 30 marks or 50 Everybody says this at home that mummy Mom, he failed, why don't you avoid him? Let's go a little bit, yes your friend I am happy to see your marks but at home The poor guy has to say that his mother has failed It has happened, it can fail, so it will look a little like this It has to happen to you too Isn't it great let's move forward Let's move forward till I understand everything Let's go with convex lenses. ok this table Here is the table in very short form I have explained it to you. Now let's come to the uses of concave Lens. Sorry, I am speaking convex. 1 minute What have you done brother? what have you done? did you write it upside down? Concave it brother. Tell me brother if there was a convex behind there, It was concave, whatever it was, correct that as well Take. Look brother, what are the benefits of concave lenses Are you used to it? Concave lens upside down concave Whose lens will work upside down? what we earlier Read from Convex. Ok? what does it do Is? It takes things away. What could I do Is? puts away. So it would have a job It is useful in correcting myopia Is. We will read about this in the next chapter. Ok? View Optical Instruments here All your optical instruments There are many. especially what I I told you in the beginning that which is a hole so that you can see who is outside Are you standing near the door? This lens is inside that hole Seems like Which lens? Concave lens. Let us go. Apart from that there are laser flash lights, right? Very all the lasers you have which Have to go away. Isn't it? spread so far It happens. so for that because look at this What is the work? What will the lens do? These lenses which He will spread things like this. Isn't it? then respect Suppose you want to spread a light like this Is. So use this same lens there. It is going to happen. Ok? where you see the light needs to diverge. such as laser Flashlights & Beam Expanders. Ok? Laser Flashlights & Beam Expanders. These Your torch light. Look what happens to the torch light It happens? Like it has to spread. so over there Which lens is used? Concave. Very well confused son i know somethin it is confusing concave convex concave son at the convex when you remember her number you can do this much you can do it okay Come on brother let's see this question is very cute Let's see a study of how to mark stars in which three different types of convex lenses a b c this is the same question this is what we did in the mirror, these are different Types of convex lenses are their focal length length 15 20 and 12 okay and this object The distance of where the object is placed Gaya is asking in question in one of the above case will the lens form the virtual Image? When does a lens form a virtual image? Memory Which lens is the virtual image? Convex lens. Convex Lens Virtual forms an image only in the case when the object We place it between the optical centre and F1. Give. Ok? What is a good focal length? Look at the focal length, it is 12. Its 20. It has 15. if you look carefully first The focal length of the case is 15. That means here The distance from there to here is 15. But The object is only 10 cm. It is kept on. Isn't it? if from here to here The distance is 15 and the object is just 10 Cm. If it is placed on it then what kind of image will be created? Yes, virtual and erect. Come on, the first one I got the answer. List to properties of the Image formed in case two. What is case two? Let us look at case two. The focal length is 25 and We have an object with a focal length of 20 and We have placed the object at a distance of 25 cm. It is kept on. That means, if you imagine it a little can you do it son like this look this is f1 na which is how much? 20 cm And we've The object is placed here. i.e i.e. between f1 and 2f1 between this is in. So how was the image created? Real and It was made inverted, where was the butt made? think think think where were you made use your mind Think about it, it is not coming quickly Friend son how will it work like this friend so many I have made a diagram, I need a trick for this too I will tell you the trick for this too, don't worry about it I will also tell you the trick, the image that was formed Big was made behind the banner 2f2f2 The image was created, it became real and say yes inverted let's what's next what is the the nature and the size of the image formed by the Lens A: What kind of image did Lens A create as a virtual one? Made it erect and made it big, large made it because you already know the case Special case. Let a lot of kids trick you They are asking for it. So come brother for the lens too Let me give you the trick. Come on brother. six cases what is the trick bhaiya? So you have it PK Trick. You have the PK trick. Come Go brother, quickly. Look brother, don't do anything. Numbering is the same, you know counting right? Friends? if you know counting then You don't have to do anything. do the counting Is. Come on brother. Let's do the counting. Isn't it? 1 2 3 we will do it just like this. One will be one Infinite. 1 2 3 4 5 6 Now start the same counting from here. What's the problem? what's the problem, son? Start from here. Same counting. What want to do it? Look, son. Keep watching. one two Three four five. Five will be on infinity. Ok? Five. and the sixth case It is always special. in the sixth The image itself was created on virtual platform. Isn't it? So now What did I want to tell you with this? If The object is on one i.e. it is on infinite So where will the image be created? One pay i.e. f2 pay. very nice. if binard is 2f1 then image Where will it be made? Look, where is this being made? This to pay. i.e. between f2 and 2f2 is the same Bean thing. if it's on three then where is the image will it be made? It will be made on three. Isn't it? if on four If it is there then the image will be formed on four. If Five Pays So the image will be formed on five i.e. infinity. I Le Magic. Aile Jaadu Bhaiya what happened? It's not magic, son. This is a trick. Is No? These are very simple tricks. I Hope you have understood all these things. Let's move ahead quickly. ok one thing tell me. tell me one thing that sign Did you understand it in the convention mirror? They Applying the same sign convention to your lens Is. What was the sign convention? anything to if left then negative, if any thing Right so positive. Positive up, positive down Negative. It's the same bean. Nothing is different. I will not change the sign convention. I I will keep the beans and from that all your I will get the numerical solved. Ok? Bus This is where the formula changes. Nice Mirror What was the formula? 1/v + 1/u = 1 / f Now just a negative sign appears here goes. Remember this sign. This which you You can see the minus sign, isn't it? It is important. 1 / v - 1 / u 1 / f v What is? Distance of image to object Distance Focal Length. Ok? Well now You think for yourself and tell me which lens is this which one is it? Convex. its focal length will it be positive or negative? its focal length Where are you, my son? on both sides Is. Oh no no, where does he create the image? It creates this image in this direction. Right? Right? Yes. That means on the right side. Focal Length How will it be? Positive. well what about it Was? Keep telling me quickly, son. With this What is? my drawing is very dangerous Son. Where was its focal length determined? This In direction. So its focal length will be That will be negative. How do you remember this bro do? Look, whether it is a mirror or a lens. Concave mirror and lens both will always have Negative focal length. Concave Lens and Concave Mirror and Convex Mirror and Convex The lens will always have positive focal length. Remember it like this. Whether it is a mirror or a lens or focal length Length. It will remain the same. Ok? Very true. So now I understand this formula. Good There is also a thing here called magnification. The magnetism is the same. Height of Image Divide By height of object. but its flower has changed goes. Its swell becomes v / u i.e. That negative sign gets cut off. He moves away. Ok? sign of negative Removed it. That's it. Correct. very nice. Good. Now what is this magnification will you tell me here? same thing like mirror I was there for magnification, if it came out negative So real plus inverted. if it comes positive So virtual plus erect. It's the same, son. Some? It is not changing. That story is completely the same. Let us go Now comes an important topic. The important topic is the power of the lens. From this 10001% an easy question comes. What is power Is? What is my power? how much in me Do you have strength? Similarly the power of the lens is called Ability to converge and diverge light. These What will the lens do? It will converge. these lenses what will he do? will diverge. so what would have happened Is? Ability. Ability to Converge and Diverge the light is called power of the lens. Ok? What is power? Ability to Converge Or dive. Or we will convert it Or we will diverge. I will call that one of the power lens. Ok? what will you say? Power. what is the SI unit of power Is? The SI unit of power is Dioptier. what happens son? Dioptier. Ok? Remove the meter Dioptier. Ok? What happens? d these It is the SI unit of power. ok sir? Very true. Good. now this is the power What is its formula? So the power of The formula is 1/f or 1/focal Length. But remember son, it would be a mistake. Focal Length here is in meters. In which? meter and the focal length in all the questions It is in centimeters. you have You must have noted it. then change this flower to write Take. Power equals 100 / f when f is in? In centimeters. What happened to the formula? 100 /f. Remember this formula because it It will be useful. Ok? What is the unit of power? Dioptier. Ok? now accept it accept it The question arises how to define one dioptier. define You will do it. what will you say? one dioptre is The power of the lens whose focal length is 1 meter. whose focal length satisfies this formula See. whose focal length is 1 meter, What will the power be? His power will also be 1 Dioptier. Yes or no? Yes or no? Very Correct. Very true. Let us go. ok now understand this My two lenses are convex. Convex The focal length of the lens is positive. Concave key is negative. This means that that the power of the convex lens will be How will it be? That too will be positive. Because Brother, it is clearly visible, friend, the formula What is? 1 / F. Now suppose if the focal length If it is negative then what will be the power? Negative. If focal length is positive then power Also positive. So remember the convex lens. The focal length of is positive. Negative of concave. very nice. You have understood this as well, right? Now let's ask a question. From that, you get more You will get clarity. The focal length of the lens is 25 cm Tell me brother what will happen? What is power will it be? There is power. Look, it's a centimeter. Yes yes I got caught. Putting the formula right Was. what will come? 4 dioptres. Four Dioptre. Now when will this ever be in question He asks if there is a lens. There is a lens Reverse question whose power is +4 Dioptre. Ok? Now tell me which one is this Is there a lens? Its power is positive. whose focal length is positive. whose focal length Was it positive? Convex. very nice. So this lens will be the same as the convex lens of +4 dioptre. well in this question If someone asks you to find the focal length Take. How will you get it out? you know the formula Is. Isn't it? Do you know the formula? Ok? Now we know the power. power is 4 Dioptre. Ok? so what is the focal length Will she go? Take it here. take it here Go. So the focal length will be 100/4 that Is equals to 25 cm. look and tell me did you understand this thing Son? very nice. very nice. what's the matter Is. brightened up. Isn't it? So such power and this Focal length. All these questions arise. Sometimes Sometimes such questions also come up that this is a There is a lens. This is a convex lens whose power is is +2 dioptriad. and added it With a concave lens whose power is -4 Dioptre. Ok? So now their net power is Tell. So how will you tell the net power? Nothing to do. Both have to be added. this +2 this -4 How much will it cost? What is the net power Will she go? The net power will be -2 diopters. So Sometimes normal questions come like this too Are. More easy ones are available. means from here The questions are not that hard. Right? Quick Tell. Did you understand it? Ask questions. the focal length of the four convex lens pqrs r 20 15 5 and 10 cm v lens will you will have the greatest power if you follow the formula If you have noticed, this is the formula whose Focal length is less and its power is more, yes or no friend what are you doing brother yes yes whose the focal length is the shortest it is visible it is visible is r r r r r r r And isn't it? So whatever will be R, its power will be the highest It will be more. good who has the least power You will tell me that in the comment section. Let us go Let's move ahead. focal length of the convex Lens is 10 cm. if the object is Placed 15 cm. away find the position and Nature. Now they have become numerical. Solve this quickly. try to solve it To do. I get it done too. Who this were you able to solve it? By the way, the question is not that tough It was not there. It was a basic question. Look at the most Let us write down the givens first. Convex Lens The focal length is 10 cm. Convex The focal length of the lens is plus. positive it occurs. I told you, right? Yes that is correct. Mirror Whatever the lens, it is always positive. Correct Is? The object is u. of the object The distance is always negative It happens. I also told you this because he always It is kept on the left side. Ok? Image that is we have to tell v and its Nature. How do you find out the nature? With magnification. Ok? Look now What does the formula say? this is it son Formula. what is this? Lens Formula. very nice. Now in this you just What to remove? v has to be taken out. Isn't it? U What is the value of? -1 /15 f what is the Will you go? 1/f What will come? 1/10. Ok? This negative negative will become this positive. This will become completely positive. it here If you transfer it will become negative. Look at the calculations, son. The game happens. Ok? Did everyone get this? Tell me quickly. Very true. Now tell the LCM What's coming? Our LCM will be 30. The LCM taken is 30 right? This one got 3 - 2 So this is your 1/30 of 1/v The value of v is 1/30 then the value of v is Your 30 cm will go. that is, the object's The image of the distant object that has been received The distance came to 30 cm. Ok? What Tell me where it will be? Positive 30 cm. i.e Remember me brother. Where is the right side? Right An image was formed on the side. very nice. Well now I have to explain the nature. How do you describe nature? By magnification. Here is the son minus the hut I remember a lot in magnification I know you remember I remember okay okay yes okay so here it is 30 divided by what is u u is -15 u is -15 so this is Your -2 will go how much did it come -2 this minus What are you saying son, it is saying minus that the image is real and inverted so what can I tell you It seems that the size of the image is double As compared to object, I understood these memories I am lost son, remember one thing never trust things in life to do. Girls' Instagram DP And on the love talks of boys. Sarah Keep the focus on the master. Ok? Yes. look come Did you understand? Let us go It is done. Brother, let me ask you one more question. I will ask more questions just for fun. Come on. A The object is placed at a distance 15 Cm. From concave lens. i.e. u's The value given to us is -15. U is always minus will be. Focal length of a concave lens. ok this What is the focal length of a concave lens? Is? It is positive, right? Yes. Whether mirror Whether it is a lens. find the position and the nature of the image form. also draw the ray Diagram. Don't tell me anything brother. Remove the V And also show the ray diagram. ask this It is happening friend. What's in it? To remove the V Take it brother, put it in brother. Glory to Lens Fulla yes. what are you brother? Hail Lens Fulla. Let us go Brother. Isn't it? Minus minus is plus Will go. Now let me do the calculation quickly I have been. So keep your focus very high. If the focus If removed, an accident will occur. this i guess same There is a question. this i guess same question Is. Isn't it? because all the values are There are beans. all the values are the same it is just that. Isn't it? I guessed it all The values are coming out the same, son. Check Do it quickly. what's coming your anser? Is the answer coming? Quick Tell. 1 / v - 1 / u Who is this to you? 1 minutes. 1 minute 1 minute. we did one thing wrong I have taken it. Sorry sorry sorry sorry. it is concave There is a lens. The focal length of the concave lens is Bhaiya it is negative friend. What are you doing Buddy? What are you doing, brother? Isn't it? What to do had been? Tell me brother. It's negative, friend So. This is wrong brother. let's talk about nothing No. I did not see it, brother. Big Mistake It's done. I am sorry. Minus this. Is No? Put a minus here. minus here too Apply it. ok sir? It's fine now. It's fine now. Are you happy? Let us go. Now take the LCM. ok sir? 30 30 How much is this? -3 and -2 then this comes will go to -5/30 and this will come to -1/6 so that means The value of 1/v is i-1/6. This means that that the value of v that will come out will be -6 Cm. What happened, son? -6 cm What Did everyone get the same thing? Tell me quickly. Is this the case with everyone Came? very nice. very nice. here comes the Everyone's. Now we have to explain the nature. How Nature Do you take it out? Magnification son. What else? What is the value of v / u v ? The value of V is -6 and the value of U is -15, right? so this Minus will be deducted from minus. What will come of this Son? 2 / 2 / 5 2 / 5 here it is Magnification. Magnification Positive Image Virtual Erect. very nice. very nice. well there was one more question in this that was also a draw The Ray Diagram. Draw a ray diagram and show Two. Isn't it? Hey, you make a diagram and show me. You can. Re you make the diagram yourself and show me You can. This is your concave lens. Ok Son? and you know that its focal point The length is f1, what is it? 10 cm And we have made the object 15 cm. placed on the Is. That is, we have placed the object somewhere here It has been kept. Ok? then you can draw its ray diagram You can make it yourself and show it like this. Isn't it? Focus and the other light ray will pass through optical The image from the center would be somewhere here It will be made. Isn't it? The image will be created somewhere here. Ok, that's great. Done. So many such The questions come. Isn't it? Very true. Let us go. These Last question of the day. After this, you will have a I will give you homework questions which you can answer in the comments Will you tell me? Then our chapter ends. oh yes Yes. What a feeling I am having friend. so big I have completed the chapter, come back. An object is Placed at a distance 30 cms. from the Convex lens. our dear one It is a tiny little convex lens. from that We have placed the object at a distance of 30 cm. That means U's The value is -30 cm. ok sir. What else it is said that the image is formed on a Screen place 20 cm. The image said it. Image means we have V given. what did v say Is? That the image that is formed is 20 cm. Pay It is made on the other side. i.e. the object It was here and the image was created here. positive Will you take it or negative? Don't do wrong. Right Side I am positive. very nice. So this will come plus of 20 cm. Ok? what are you asking? Calculate the focal length. Just do nothing. I need to find out the focal length. Tell me friend bro. Are Such an easy question. Tell me brother. The value of v What is? 120 minus and look here's another minus yes son. Another look is the calculation game. I am speaking again. Whole game calculation minus minus plus so 120 + 1/30 LCM Take. The LCM will come to 60. Look at the LCM I have practice so I can do the calculation I am speeding it up. your practice is It will go with time. Ok? So here it comes 5 / 60 Finally if you divide this then it will be It will be 1/1/12, right? then the sum of 1/f The value came to be 1/12. then what is the value of f I? The value of f came to be 12 cm. See more It is positive. What does positive mean? Is it a convex lens? of convex lens The focal length is then positive. what's the matter Is? what's the matter? Okay, I have come. also state Whether the image is real or virtual. Image It's real bro. We know it clearly. Isn't it? Is No? It was written here that Screen place 20 cm. away on the other Side. The image is on the other side. On the other side The image is created i.e. it is a real image. Ok? If If the same side image is formed then it is a virtual image. These This was your whole cute little Chapter. Here is yours. Comment right now From. I want all the questions solved. So much You worked so hard son I have told everything. here it is The chapter ends. Listen to me. Now I want to talk to you for 2 minutes. look sometime Sometimes I know you think that this Life is very tough. Ok? I am a little I am sharing the story so that you know When I was in college I had to Life seemed very tough. one time i'm going to I was in college and that guard brother was there No, they are asking me why my friend is so worried Why is it? So I was filled with joy from within. I narrated it to him. I said hey brother How do you know how tough my life is. I am doing this. I am doing that. Some? I am not able to understand it. college is not maintained Used to be. this is it. Where is the attendance from Should I bring it? So many. I heard everything Gave. He did not start smiling. He began to laugh and he smiling He said that Prashant you don't know what is tough life? difficult life what happens? when you get a job as a guard You have to do this in which you get ₹10,000 per month And within that ₹10,000 you will get your two have to pay children's school fees and You have to drive the auto at night so that you can bring home food Get it. That is a tough life. And I heard this thing the other day and I As soon as I heard it I understood that our friend Where is life tough? There are a lot of people like us Whose life is 100 times tougher than ours. Isn't it? And from that day onwards I thought that now No matter how many problems I face I won't give up I will agree. And today I am giving you this thing because I am telling you that life will be tough. don't give up We have to agree, we have to stand firm, we have to keep standing. Isn't it? This passion or emotion should be inside. then You will actually be able to become a hero. So this o What photo have you posted? So what does the light say? Used to be? Let's end the chapter. Reflect Positivity, Refract Negativity and Always focus on your goal. Always focus on the goal I will do it on this note. Thank you everyone. I I am yours Prashant Bhaiya. if these I liked the video, I mean it's complete If you liked the lecture then share it on Instagram Please do tell me by putting a story. Instagram In the description whether you enjoyed it or not, Did you understand it or not? Come on take care. Next Which lecture do you want? Definitely in the comment Narrate. Bye-bye go bye.