Light-reflection and refraction/CBSE/Grade-10/Physics

Hinzugefügt: 2026-05-26

[00:00:36]Hello. Hi everyone. Welcome to the student the brand. This is our sir.

[00:01:50]Hello. Hi everyone. Welcome to the student the brand. This is so today topic is uh light reflection and refraction CBSC grade and physics. So we'll discuss uh briefly about the topic. So let's start the topic light reflection and refraction light.

[00:02:37]So light reflection and refraction light is a form of energy which gives the sensation of light. When light incident on the surface it reflect back.

[00:02:47]So the bouncing back of the light from the reflecting surface is called reflection of light. When light incident on the surface it reflect back yes or no. So here so we'll discuss about incident ray reflected ray normal line.

[00:03:46]So let's start the topic. So we'll discuss about incident ray reflected ray normal line.

[00:03:55]Okay. So the bouncing back of the light from the reflecting surface is called reflection of light. So in light reflection refraction. So mainly we'll discuss about uh reflection of light and um we'll discuss about the loss of reflection, angle of deviation. Uh so after that uh we will discuss about uh regular reflection and irregular reflection, regular reflection and uh irregular reflection. So after that we will discuss about object and image.

[00:04:31]Object and image. After that nature of the image formed by the plane mirror.

[00:04:35]Nature of the image formed by the plane mirror. So after that we'll discuss about spherical mirror. Spherical mirror. Concave mirror. Convex mirror.

[00:04:45]After that terms related to spherical mirror. So after that ray rules and image formations by spherical mirrors.

[00:04:54]After that okay so we'll discuss about sign conventions. After that refraction.

[00:05:02]Okay. So refraction uh like a light ray passing from rare to denser bends towards normal. If it is passing from denser to rare it moves away from the normal line. So all those points we'll discuss one by one. Okay. So mainly we need uh okay so after that completion of that after completion of refractions we'll discuss about light passes through the glass slab. Okay. So refraction through the glass lab. After that we'll discuss about spherical lenses, spherical lenses, ray rules and image formations. Okay. So we'll discuss one by one all the points. Let's start discuss about it. Let's start discuss about here. You can see here when light ray is passing from when light is passing from rarer to dens bends towards the normal line. Okay. So here I'm taking incident ray.

[00:05:56]This the normal line.

[00:05:59]Normal line.

[00:06:01]Okay. So incident reflected normal line.

[00:06:13]So I'm taking the plain surface here. I'm taking incident ray.

[00:06:21]So normal line. This a normal line.

[00:06:26]Okay. So normal line this a plain surface one side is reflecting surface and the reflected ray reflected ray understood or not incident ray reflected ray normal line incident ray reflected ray and normal line. So here you can see so the angle between incident and arm line is called angle of incidence angle between reflector and normal line is called angle of reflection. So generally light moves in a straight line path light moves in a straight line path. So here I'm taking this the undeviator line and deviator line. Okay. So the angle between reflector ray and deviator line is called angle of deviation.

[00:07:23]Angle of deviation understood once again. So incident reflected normal line. Angle between incident r normal line is called angle of incidence. Angle between reflector and normal line is called angle of reflection. Angle between reflector and undevated line is called angle of deviation. Angle of deviation. Understood or not? So I hope it is very clear. So next one. So the angle between incident and plane surface is called glancing angle of incidence.

[00:07:55]Angle between reflected and plain surface is called glancing angle of reflection. Glancing angle of reflection. So I hope it is very clear.

[00:08:05]So coming to the next one is loss of reflection. Loss of reflection. So let's discuss about loss of reflection.

[00:08:14]and loss of reflection.

[00:08:18]And here incident reflected normal line.

[00:08:24]Incident reflected normal line lies on the same plane. Incident reflected normal line lies on the same plane. And coming to the second one, angle of incidence is equal to angle of reflection. Angle of incident is equal to angle of reflection. So these are loss of reflection. Loss of reflection understood or not? So I hope it is very clear. Once again incident reflected ray normal line. Angle between incident ray and normal is called angle of incidence.

[00:08:56]Angle between reflected and normal is called angle of reflection. Angle between reflected ray and devator line is called angle of deviation. So angle between incident r and plane surface is called glancing angle of incidence.

[00:09:10]angle between reflected and plain surface is called glancing angle of reflection.

[00:09:15]I hope it is very clear. So coming to loss of reflection.

[00:09:20]Loss of reflection inside a reflected normal line lies on the same plane.

[00:09:26]Angle of incidence is equal to angle of reflection. Angle of incidence is equal to angle of reflection. So I hope it is very clear. So coming to the next one here. So angle of incidence plus angle of reflection plus angle of deviation equal to 180°. As we know that angle of incidence plus angle of reflection plus angle of deviation equal to 180°. From loss of reflection what we can write angle of incidence is equal to angle of reflection. Right? Angle of incidence is equal to angle of reflection. know that.

[00:10:04]So we can take angle of incidence plus angle of incidence plus angle of deviation equal to 180° angle of deviation = 180 minus 2 angle of incidence angle of deviation equal to 180 minus 2 angle of incidence. So we can also take angle of deviation equal to 180 minus 2 angle of reflection. So how can we write angle of deviation equal to 180 minus 2 angle of reflection here in the place of angle of reflection in the place of angle of reflection if I write angle of incidence then we'll get we are getting angle of deviation equal to 180 minus 2 angle of incidence so in the place of angle of incidence if I write angle of reflection then angle of deviation equal to 180 minus 2 angle of reflection understood or not? So I hope it is very clear. So this is about reflection of light. The bouncing back of the light from the reflecting surface is called reflection of light. The bouncing back of the light from the reflecting surface is called reflection of light. So incident ray reflector ray normal line. So the angle between incident ray normal line is called angle of incidence. Angle between reflector normal is called angle of reflection.

[00:11:23]Angle between reflector and deviator line is called angle of deviation. angle of deviation and one more thing. So angle between incident r and plane surface is called glancing angle of incidence. Angle between reflected and plane surface is called glancing angle of reflection. Okay. So coming to loss of reflection. Incident ray reflected ray normal line lies on the same plane.

[00:11:47]Angle of incident is equal to angle of reflection. Okay. So I hope it is very clear here. Now we can observe angle of incidence plus angle of reflection plus angle of deviation equal to 180°. Angle of incidence plus angle of reflection plus angle of deviation equal to 180°.

[00:12:06]So in the place of angle of reflection I'm substituting angle of incidence then I'll get angle of deviation equal to 180 minus 2 angle of incidence. in the place of angle of incidence if I substitute angle of reflection then I'll get angle of deviation equal to 180 minus 2 angle of reflection okay so I hope it is very clear now so we'll discuss about so now we'll discuss about regular reflection and irregular reflection. So now we will discuss about regular reflection and irregular reflection. So what do you mean by regular reflection and irregular reflection? So here you can see so I'm taking the plane surface here plain surface.

[00:13:03]Okay. So incident light rays are parallel. Then these are incident light rays. Incident light rays are parallel.

[00:13:14]Then reflect light rays are also parallel to each other.

[00:13:19]Incident light rays are par. Then reflect light rays are also parallel to each other. So this type of reflection is called regular reflection. Regular reflection. Understood or not? Incident light rays are par then reflector light rays are also parallel to each other.

[00:13:37]Incident light rays are par then reflector light rays are also parallel to each other. understood or not? So regular reflection regular regular reflection regular reflection. So incident beam parallel incident beam. So here you can see regular reflection.

[00:14:05]Regular reflection.

[00:14:10]Regular reflection here. Incident parallel beam.

[00:14:16]Incident parallel beam.

[00:14:21]And here reflected reflected parallel beam.

[00:14:33]Okay. So this is about regular reflection.

[00:14:40]So this is about regular reflection.

[00:14:43]Coming to irregular reflection.

[00:14:45]Irregular reflection. So here you can see.

[00:14:50]So irregular reflection.

[00:15:03]Okay. Incident light rays are par then reflector light rays are also par to each other.

[00:15:10]So here you can see these are incident light rays.

[00:15:20]Incident light rays are par then reflector lighters are not parallel to each other.

[00:15:27]So these light rays are moving in different directions.

[00:15:33]So here in regular reflection incident uh so this is about regular reflection in regular reflection incident light rays are par then reflector light rays are also parall to each other.

[00:15:49]Yes irregular reflection or diffused reflection. So irregular reflection is also known as diffused reflection.

[00:15:56]Irregular reflection is also known as diffused reflection. understood or not?

[00:16:01]So I hope it is very clear once again.

[00:16:04]So observe carefully. So regular reflection, regular reflection, incident light are parallel. Then reflect light rays are also parallel to each other.

[00:16:13]Coming to irregular reflection, incident light are parallel but reflect light are not parallel to each other. So irregular reflection or diffused reflection.

[00:16:23]Irregular reflection are diffused reflection. So I hope it is very clear.

[00:16:27]So this is about regular reflection and irregular reflection. So coming to the next one.

[00:16:34]Coming to the next one. And here one more point. Regular reflection takes place on smooth surface whereas irregular reflection takes place on rough surface. Regular reflection takes place on smooth surface whereas irregular reflection takes place on rough surface. Understood or not? Yes.

[00:17:09]Coming to the object and image.

[00:17:12]Object and image.

[00:17:15]So we'll discuss about object and image.

[00:17:17]Let's discuss about object and image. So here I'm taking the plane mirror.

[00:17:28]So lighters are coming from the point.

[00:17:39]Okay. So after reflection light rays are meeting at one point. After reflection light rays are meeting at one point. The point of intersection of incident light is called real image. The point of intersection of incident light is called real image. Okay. So this is a real image. And if you're extending this light rays, so here virtual object is there. Virtual object. Virtual object.

[00:18:10]Understood or not?

[00:18:12]So the point of intersection of the point of intersection of reflectitis reflect it directly meeting at one point that point is called real image. Whereas extended incident lighters are meeting at one point. Extended incident light are meeting at one point. So that point is called virtual object. That is called virtual object. Understood or not? So and one more thing here you can see.

[00:18:46]So from the point light rays are coming this is the point from this point light rays are coming.

[00:18:54]So that point is a real object this point is called real object. So after reflection this is a real object. Real object light rays are coming from this point. After reflection those light rays are moving away from it. So here you can see these light rays are moving away from it like this.

[00:19:20]Understood or not? So here if you are extending this light rays extended reflector light rays are meeting at one point that's a virtual image. Virtual image real object and virtual image real object and virtual image. Understood or not? So here you can see so in this point so directly light tracer meeting at one point directly light tracer meeting at one point reflect a light ray. So this is called real image. The point of intersection of reflector light rays is called real image. And here you can see we are extending the incident light rays. Extended incident light rays are meeting at one point their virtual object is there. and coming to here. So from this point light rays are coming.

[00:20:10]From this point light rays are coming after reflection those are moving away from it. Those are moving away from it.

[00:20:16]If you are extending this light rays extended light rays are meeting at one point. Extended reflector light rays.

[00:20:23]Extended reflector light rays are meeting at one point. Their image is forming. That is a virtual image. That is a virtual image. So we can conclude that we can conclude that from these two diagrams from these two diagrams we can conclude that object and image object is real image is virtual object is virtual image is real. Understood or not? If the object is real, image is virtual. If the object is virtual, image is real. So here you can see so object is real. This is a real object. This is a real object.

[00:21:00]What about image? Image is virtual.

[00:21:03]Object is real. Image is virtual. And coming to the object is virtual. This is the object virtual. What about image?

[00:21:11]Image is real. Image is real. Understood or not? So vice versa. If the object is real, image is virtual. If the object is virtual, image is real. Understood or not? So this is about nature of the image. Okay. Nature of the image. So virtual image and real image. virtual object and real object. Okay. So here you need to understand one thing if light rays are directly meeting if those light rays are meeting directly that that image or object. Okay. If light rays incident light rays are meeting incident light are coming from the point that is a real object. So reflector light rays are meeting directly that is a real image. Extended reflector light are meeting that is a virtual image.

[00:21:57]extended incident light traer meaning that is virtual object virtual object so I hope it is very clear so that's enough so this is about object and image object and image so next one we will discuss about nature of the image formed by the plane mirror nature of the image formed by the plane mirror let's discuss about it let's discuss about it nature of the image formed by the plane mirror So nature of the image nature of the image formed by the plane mirror. Let's discuss about it. Okay. So here you can see so plane mirror. This is a plane mirror, right? Yes. So here I'm taking this object this object A and B. So plane mirror.

[00:23:03]Okay. How many light rays are required to form the image of the object? Minimum two light rays are required to form the image of the object. Yes or no? How many light rays are required to form the image of the object? Minimum two light rays. So one light ray I'm taking like this. So when light ray is incidenting along the normal line, if the light ray is incidenting along the normal line like this, so it will be reflected back into the same path. It will be reflected back into the same path. Understood or not? Yes or no? So I hope it is very clear, right? Yes. So here if the lighter is moving along the normal line so it reflect back and one more lighter I'm taking like this. So after reflection it is moving away from it.

[00:23:52]And here if you are taking like this so those light rays are moving away from it. Okay. So if you're extending this light rays extender light are meeting at one point here you can observe Here B dash and A dash.

[00:24:33]Here B dash.

[00:24:36]B dash and A dash. B dash and A dash.

[00:24:40]Okay. So if the object is real, image is virtual. Object is real. Image is virtual. So object is real.

[00:24:49]Image is virtual. Object is virtual.

[00:24:52]Image is real. So coming to the second point. So object distance is equal to image distance.

[00:25:00]Okay. So object distance is equal to image distance.

[00:25:05]So here you can see the distance between object to mirror is called object distance. The distance between mirror to image is called image distance. And here you can see the height of the object. So this the height of the object. And here you can see this the height of the image. Height of the image.

[00:25:26]Okay. So third one is height of the object is equal to height of the image and fourth one magnification of the plane mirror is + one.

[00:25:39]Magnification of the plane mirror is + one. So what do you mean by magnification is + one? Height of the image by height of the object. Height of the image by height of the object. And coming to the fifth one. So it also shows lateral inversion.

[00:25:55]Lateral inversion.

[00:25:59]So lateral inversion. What do you mean by lateral inversion?

[00:26:04]Okay. So first one object is real, image is virtual, object is virtual, image is real. So second point is object distance is equal to image distance. And height of the object is equal to height of the image. And the next one magnification is + one. Magnification is + one. And it also shows lateral inversion. So what do you mean by lateral inversion? Lateral inversion is nothing but the phenomena of converting of right side of the object appears to be left side of the image. Left side of the object appears to be right side of the image. So that mirrored image is called lateral inversion. Lateral inversion. Understood or not? So I hope it is very clear. This is about nature of the image formed by the plane mirror. Nature of the image formed by the plane mirror. Okay. So let's see one look at once.

[00:27:40]Okay. So next one we will discuss about next one. So we are going to discuss about spherical mirror. The mirror which is in the form of curved surface. So let's start discuss about it. Spherical mirror.

[00:27:59]Spherical mirrors.

[00:28:27]spherical mirror. So what do you mean by spherical mirror? The mirror which is in the form of curved surface. Okay. The mirror which is in the form of curved surface is called spherical mirror. The mirror which is in the form of curved surface.

[00:29:36]Okay. So the mirror which is in the form of curved surface is called spherical mirror. So there are two types of spherical mirrors. One is concave mirror, another one is convex mirror.

[00:29:48]One is concave mirror, another one is convex mirror. Let's discuss about it.

[00:29:53]So here so concave mirror is also known as converging mirror.

[00:30:06]Concave mirror is also known as converging mirror. So why? So here you can see when our light rays are incidenting on it. After reflection those light rays are meeting.

[00:30:20]So after reflection those light rays are meeting towards the principal axis. Understood or not?

[00:30:26]Whenever refle whenever light rays are incidenting on it after reflection those light rays are meeting at one point.

[00:30:33]Okay. That's why concave mirror is also known as converging mirror. Concave mirror is also known as converging mirror. Concave mirror.

[00:30:45]Concave mirror is also known as converging mirror.

[00:30:54]Converging mirror. Whereas convex mirror.

[00:30:58]So here you can see.

[00:31:01]So pole focus center curvature pole focus and center curvature after reflection. So light rays are moving away from it. Light rays are moving away from it. So here you can see after reflection those light rays are moving away from it. That's why. So if you like the content if you like the channel do like share and subscribe to story in the brand. Share to everyone.

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[00:31:41]Okay. So here you can see this is about convex mirror. Convex mirror is also known as diverging mirror. Convex mirror is also known as diverging mirror. Okay.

[00:31:54]So this about diverging mirror.

[00:31:58]diverging mirror.

[00:32:02]Okay. So concave mirror concave mirror is also known as converging mirror. So why concave mirror is also known as converging mirror. Whenever light rays are incident on it after reflection those light rays moving towards the principal axis that's why concave mirror is also known as converging mirror.

[00:32:19]Whereas convex mirror whenever light rays are incidenting on it after reflection the light rays are moving away from it. That's why it is called diverging mirror. So concave mirror is also known as converging mirror. Convex mirror is also known as diverging mirror. So now we will discuss about terms related to spherical mirror. Terms related to spherical mirror. Let's start.

[00:33:05]So terms related to spherical mirror. So here you can see so I'm taking the pank mirror.

[00:33:20]So the center of the imaginary sphere.

[00:33:24]So the midpoint of the mirror is called pole. So this the center of the imaginary sphere. Actually is a part of the sphere.

[00:33:34]So here we are taking the center of the imaginary sphere in which mirror is a part. So midpoint of the mirror is called pole. The line joining. So the distance between center of curvature to pole is called radius of curvature. The distance between central curvature to pole is called radius of curvature.

[00:33:55]Okay. So and here after reflection those light rays are meeting at one point on the principal axis.

[00:34:03]So here you can see after reflection.

[00:34:08]So this the focus principal focus principal focus. So the distance between focus to pole is called focal length.

[00:34:17]The distance between focus to P is called focal length. Okay. So point number one, center of the imaginary sphere in which mirror is a part.

[00:34:29]Midpoint of the mirror is called pole.

[00:34:32]So the distance between center of curvature to pole is called radius of curvature.

[00:34:38]Radius of curvature.

[00:34:40]And so we can also take principal focus.

[00:34:45]And the distance between focus to pole is called focal length. And 61 width of the reflecting surface is called aperture.

[00:34:56]Width of the reflecting surface is called aperture. And so the line joining of center curvature of pole is called principal axis.

[00:35:08]Principle axis.

[00:35:13]Understood or not? So I hope it is very clear. So these are the points. One is center of the imaginary sphere in which a mirror is a part. Center of the imaginary sphere in which a mirror is a part is called center of curvature.

[00:35:28]Midpoint of the mirror is called pole.

[00:35:30]And so the distance between center of curvature to pole is called radius of curvature. After reflection all light are meeting at one point of the principal axis is called focus. The distance between focus to pole is called focal length small f and the width of the reflecting surface is called apachure and the line joining of central curvature and p is called principal axis. Okay. So these are the terms.

[00:35:58]So these are the terms related to spherical mirror. Terms related to spherical mirror. So next one we will discuss about rare roles. Rails.

[00:36:37]Okay. So now we'll discuss about uh ray rules concave mirror and convex mirror.

[00:36:44]So let's discuss about it concave mirror and convex mirror. So here concave mirror I'm taking. So every time you are drawing the concave mirror you have to mention. So pole focus center curvature.

[00:36:59]Pole focus and center curvature. So this is the pole focus center curvature.

[00:37:08]Pole focus and center curvature. Light ray is coming from infinity. After reflection passes through focus. Here you can see light ray is coming from infinity.

[00:37:20]After reflection passes through focus.

[00:37:25]Okay. So that is the first one. Coming to the second one.

[00:37:32]So pole focus center curvature pole focus and center curvature. So light ray is coming light ray is passing through focus after reflection moves towards infinity.

[00:37:50]Light ray is passing through focus after reflection moves towards infinity.

[00:37:56]So that is the second one.

[00:37:59]Second rare role and coming to third rare rule is third one.

[00:38:09]So pole focus center curvature pole focus and center curvature. So light ray is passing through center curvature.

[00:38:22]So after reflection it moves in the same direction. It retains its original path.

[00:38:28]Okay. So this is the these are three points and coming to the fourth one.

[00:38:35]So here you can see if the light is incidenting pole focus center curvature light ray is incidenting at the pole it reflect back.

[00:38:47]Reflect back. Understood or not?

[00:38:54]1 2 3 4. This is the fourth one.

[00:38:58]Fourth one. I hope it is very clear understood. So just check these are four rules of concave mirror. So in the first case light ray is coming from infinity after reflection passes through focus.

[00:39:11]And here light ray is passing through focus after reflection moves towards infinity. And here light ray is passing through central curvature.

[00:39:20]Light ray is passing through central curvature. It retains its original path.

[00:39:24]And your light ray is incidenting at the pole it reflect back. So these are four roles of concave mirror. So next one we'll discuss about convex mirror. So let's discuss.

[00:39:41]Okay let's discuss about it.

[00:39:50]So very good. Congratulations.

[00:40:07]So next one, next one we will discuss about so convex mirror. So till now we discussed about concave mirror. Next one we will discuss about convex mirror. So let's see convex mirror.

[00:40:30]So pole focus center curvature pole focus and central curvature light ray is coming from infinity after reflection passes through focus and coming to the second one.

[00:40:54]So pole focus center curvature.

[00:40:59]Pole focus and center curvature.

[00:41:02]Light rays passing through focus after reflection moves towards infinity.

[00:41:09]Coming to the third one.

[00:41:16]So pole focus center curvature pole focus and center curvature light ray is passing through central curvature after reflection it moves so it retrace its original path and coming to the fourth one.

[00:41:41]So pole focus central curvature light rays incidenting at the pole after reflection it moves.

[00:41:53]So these are ray rules of convex mirror.

[00:41:58]Ray rules of convex mirror. Here you can see light ray is coming from infinity after reflection passes through focus.

[00:42:06]Light ray is passing through focus.

[00:42:08]After reflection moves towards infinity, light ray is passing through central curvature retrace its original path.

[00:42:14]Light is incident at the pole. It reflect back. So these are four four rules of convex mirror. Convex mirror.

[00:42:23]Next it will discuss about image formations.

[00:42:29]Image formations.

[00:42:54]So image formations.

[00:43:01]So image formations by concirror. Let's discuss about it.

[00:43:07]So here you can see first one. So I'm taking the point camera like this.

[00:43:26]Oh thank you so much Sahil.

[00:43:32]Thank you.

[00:43:35]So pole focus center curvature pole focus and center curvature.

[00:43:44]So now object is placed at infinity.

[00:43:49]Object is placed at infinity. One light I'm taking like this. So after reflection those light rays are moving.

[00:43:58]Here you can see object is placed at infinity. image is formed at f. Nature of the image is real and inverted.

[00:44:09]Size of the image is highly diminished.

[00:44:12]So object is placed at infinity.

[00:44:15]Object is placed at infinity. Image is formed at focus.

[00:44:20]Okay. So nature of the image is real and inverted. Size of the image is highly diminished. Size of the image is highly diminished. Understood or not? So coming to the next one, second one here you can see here.

[00:44:40]So pole pole focus center curvature. Pole focus and center curvature. Object is placed beyond center curvature.

[00:44:54]Object is placed beyond center curvature. So one light I'm taking like this.

[00:45:00]After reflection passes through focus, another light ray is passing through central curvature.

[00:45:08]Those light rays will be meeting between C and F.

[00:45:12]Okay. So, object is placed beyond C.

[00:45:19]Object is placed beyond C. Image is formed between C and F.

[00:45:25]Between C and F. Nature of the image is real and inverted.

[00:45:29]Nature of the image is real and inverted. Size of the image is diminished.

[00:45:36]Size of the image is diminished compared to the object. Image size is reduced.

[00:45:42]Image size is decreased. Understood or not? So I hope it is very clear. So object is atinity. Image is formed at focus. So nature of the image is real and inverted. Size of the image is highly diminished. And coming to the second one, object is placed beyond central curvature. Image is formed between C and F. Nature of the image is real and inverted. Size of the image is diminished. Size of the image is diminished. Understood or not? So I hope it is very clear. So these are the two points. And coming to the next one.

[00:46:21]Third one.

[00:46:38]So object is placed at center of curvature.

[00:46:42]So third one.

[00:46:45]Third one you can see.

[00:46:48]So here so pole focus center curvature pole focus and center curvature object is placed at C. So image also will form at C.

[00:47:09]One light taking like this it passes through focus like this. Another light is incident at the pole. it reflect back.

[00:47:21]Okay. So, object is placed.

[00:47:25]Object is placed. Image is also formed at C only. Nature of the image is real and inverted. Size of the image is same size. Size of the image is same size.

[00:47:38]Understood or not? Same size of the image will form at C. Same size. And coming to the fourth one.

[00:47:47]Coming to the fourth one here you can see.

[00:47:50]Coming to the fourth one.

[00:47:56]So pole this the pole focus center curvature. Pole focus and center curvature. Object is placed between C and F.

[00:48:08]Object is placed between C and F. One light I'm taking like this. It passes through focus.

[00:48:19]So another lighter is incident at the pole.

[00:48:23]Those light rays are meeting here. So beyond central curvature.

[00:48:30]So see the image will form here. Beyond center curvature.

[00:48:36]Okay. So object is placed between C and F. Image will form beyond C.

[00:48:44]Bey and see nature of the image is real and inverted. Size of the image is enlarged.

[00:48:53]Size of the image is enlarged compared to the object. Image size is increased compared to the object. Image size is increased. Understood or not? So coming to the fifth one. So fifth image formations are there. Fifth one I'll explain.

[00:49:38]So Pole focus center curvature pole focus and center curvature object is placed at F one light I'm taking like this it passes through focus another light is incident at the pole it reflect so object is at f image is forming at infinity nature of the image is real and inverted size of the image image is highly enlarged.

[00:50:12]Highly enlarged. Size of the image is highly enlarged because at infinity the image is formed. Okay. At infinity image is formed so highly enlarged. Understood or not? So I hope it is very clear. So coming to the sixth one. Sixth one is very very important.

[00:50:35]Sixth one is very very important. 61 so three marks question so expected for board exam three marks question just check once here I'm taking the concave mirror so pole this the pole focus center curvature pole focus and center curvature so object is placed between F and One light I'm taking like this it passes through focus.

[00:51:12]Okay. One light I'm taking passes through focus. Another light is incident at the pole. It reflect.

[00:51:21]Okay. So here you can see object is placed between F and P. Object is placed between F and P. One light I'm taking passes through focus. Another light incident at the pole. So if you're extending this light rays, so extended light rays are meeting here.

[00:51:42]So behind the mirror.

[00:51:46]Okay. So object is placed between F and P.

[00:51:51]Object is placed between F and P. So image is formed behind the mirror.

[00:51:59]Behind the mirror.

[00:52:02]Nature of the images.

[00:52:05]Nature of the image is virtual, erect and enlarged. virtual, erect and enlarge. Very very important. Very very important. Three marks question.

[00:52:16]Virtual, erect and elded images formed at form behind the mirror. Okay. Nature virtual and erect. So enlarged.

[00:52:30]enlarging in the sense compared to the object image size is increased compared to the object image size is increased.

[00:52:37]So do like share and subscribe to student brand if you like the content if you like the channel do like share okay share to your friends share to everyone So next one.

[00:53:37]So next one we will discuss about convex mirror.

[00:53:42]Convex mirror. Let's start discuss about convex mirror. Okay.

[00:53:48]So here two cases are there for convex mirror. One is infinity case. Another one is object is placed between f P and infinity.

[00:53:59]So I'm taking here like this.

[00:54:04]So pole focus center curvature pole focus and center curvature object is placed at infinity.

[00:54:14]So one light I am taking like this after reflection those are moving away from it.

[00:54:23]Okay. Object is placed at infinity.

[00:54:26]Image is formed at F.

[00:54:30]Nature of the image is virtual, erect and highly diminished. Virtual, erect and highly diminished because point size image is formed at focus. Point size image is formed at focus. Okay. is the mirror which forms always virtual erect and diminished that that is convex mirror mirror convex mirror so we can see the fil of the traffic uh so we can see the fil of the object if you place in front of it okay that's why field view of the convex mirror is more field view of convex mirror is more understood or not so for plane compared to plane mirror and concave mirror. For convex mirror field is more that's why we are using for side view mirror that is rear view mirror.

[00:55:29]Okay, we can see the traffic behind of us. Okay, so that's enough. And coming to the next one here you can see.

[00:55:40]So convex mirror.

[00:55:48]So pole focus center curvature. Pole focus and center curvature.

[00:55:57]Object is placed here. While light I'm taking like this. After reflection it moves. It passes through focus. Another light ray is incident the pole. It reflect back. Okay. So now you can see here object is placed between P and infinity. Image is formed between P and F. So here the image will form between P and F. P and F nature of the image is virtual and erect. Virtual and erect.

[00:56:29]Size of the image is diminished.

[00:56:32]Size of the image is diminished compared to the object. Compared to the object image size is decreased compared to the object. Image size is decreased.

[00:56:42]Understood or not? So I hope it is very clear. In the first case if you observe in the first case object is placed at infinity image is formed at focus.

[00:56:54]Nature of the image is virtual erect and highly diminished point sized. And in the second case, so here you can see in the second case object is placed between P and infinity. Between P and infinity image will form between P and F. Nature of the image is virtual erect and size of the image is diminished. Compared to the object image size is decreased. So these are real image formations by convex mirror. Image formations by convex mirror. So next we'll discuss about Next we will discuss about sign conventions. Okay, let's discuss about sign conventions.

[00:58:02]So here you can see so pole focus center curvature.

[00:58:16]Pole focus and center curvature.

[00:58:19]All measurements will be taken from the pole. All measurements will be taken from the pole. In the direction of incident r all are positive. In the direction of incident r all are positive. Opposite to incident r all are negative. So here it is positive.

[00:58:36]Opposite to incident r negative. Above the principal axis positive and below the principal axis negative.

[00:58:45]Okay. All measurements will be taken from the pole. All measurements will be taken from the pole in the direction of incident r all are positive. Like object distance, image distance, focal length and radius of curvature all are positive in the direction of incident trace.

[00:59:02]Opposite to incident trace, object distance, image distance, focal length and radius of curvature all are negative. Above the principal axis, height of the image and height of the object both are positive. below the principal axis height of the image and height of the object negative. Okay. So as like you can take coordinate axis coordinate axis if you are taking coordinate axis positive x-axis negative x-axis positive yaxis negative yaxis.

[00:59:33]Okay. So here you can see so all measurements will be taken from the origin. So in this direction positive opposite direction negative above it is positive below it is negative. As like all measurements will be taken from the pole. In the direction of incident is object distance image distance focal length radius the curvature all are positive. Opposite incident object distance image distance focal length radius of curvature all are negative.

[00:59:59]Above the principal axis all are positive. Below the principal axis all are negative. So here you can see so I created a song related to this one.

[01:00:10]Okay. So seeant new sventition sino convention all distance measure from the pole.

[01:00:30]Distance are positive to along the instant is distance.

[01:00:40]Opposite to instant is distance above the principle axis.

[01:00:52]Dist below the principal axis. New cartition.

[01:01:01]New cartition sign convention. New cartition sign convention.

[01:01:10]Okay. So likewise so discussed new cartition sign conventions. Understood or not? All measurements will be taken from the pole in the direction of incident is positive. Opposite incident is negative. Above the princip is positive. Below the princip is negative.

[01:01:27]Okay. So these are all about sign conventions. These are all about sign conventions. And the next one so we can take mirror formula and magnification.

[01:01:54]So coming to mirror formula and magnification.

[01:01:58]So here 1x f = 1x v + 1x u magnification equal to height of the image by height of the object minus v by u height of the height of the male by height of the object. Sorry height of the male by height of the object.

[01:02:18]Understood or not? So that is about magnification and mirror formula 1x f= 1x v + 1x u 1 1x f = 1x v + 1x u and coming to the next one.

[01:02:40]Coming to the next one sign convention.

[01:02:42]So here till now we discussed about mirrors. So like a plane mirrors uh reflection of light, loss of reflection, reflection of light, loss of reflection, angular angle of deviation, regular reflection, irregular reflection. So nature of the image formed by the plane mirror object and image and after that spherical mirrors terms related to spherical mirrors ray rules of concave mirror rules of convex mirror image formation by concave mirror image formation by convex mirror sign conventions mirror formula and magnification. Now we'll discuss about refraction. Okay. So refraction refraction of light.

[01:03:25]So everything we'll discuss.

[01:03:29]Okay.

[01:05:04]Okay. So, let's start the topic.

[01:05:11]Okay.

[01:05:23]So next so refraction let's discuss about refraction.

[01:05:32]Refraction of light when light passes from rarer to denser at the interference of the two media it bends. at the interference of the two media the light ra understood or not so let's here so I'm taking this here you can see this a rarer medium denser medium speed of light is more in the medium that is rarer medium. Speed of light is less. Okay. Speed will be more in the rare medium. Speed will be less in the denser medium. When light ray passes from rare to denser, bends towards the normal line. If it is passing from denser to it, it moves away from the normal line. So here you can see if the light ray is passing from rar to denser.

[01:06:33]So I'm taking this the normal line.

[01:06:36]So here you can see it bends towards the normal line. The angle between incident and normal is called angle of incidence.

[01:06:44]Angle between refractor and normal is called angle of refraction. Understood or not? Angle between incident and normal line is called angle of incidence. Angle between refracted normal line is called angle of refraction. So angle between refracted and normal line is called angle of refraction. And here you can observe angle of incidence is greater than the angle of refraction.

[01:07:09]angle of incidence is greater than the angle of refraction. Understood? And here so if the light ray is passing from rarer to d so denser to rarer if the lighter is passing from denser to rarer.

[01:07:33]If the light ray is passing from denser to error, it moves away from the normal line. If light ray is passing from denser to error, it moves away from the normal line. So the angle between incident and normal is called angle of incidence. Angle between refracted normal line is called angle of refraction.

[01:07:53]Understood or not? So here in this case angle of refraction is greater than the angle of incidence. angle of refraction is greater than the angle of incidence.

[01:08:04]Understood or not? So here when light ray is passing from rarer to denser bends towards the normal line if it is passing from denser to it moves away from the normal line. It moves away from the normal line. Understood or not? So the path of the light changes when it is passing from rarer to denser. Okay. So when it is passing from rarer to density bends towards the normal line. If it is moving from denser to it moves away from the normal light understood or not so I hope it is very clear so next one so we'll discuss about uh loss of refraction that is about snails that is about snails law here you can see so here I'm taking like this this Arban line ray is passing from rarer to denser.

[01:09:04]This a rarer medium denser medium.

[01:09:08]Light ray is passing from rarer to denser. Understood or not? So here if it is passing from rarer to denser, the angle between incident and normal is called angle of incidence. Angle between refractor and normal end is called angle of refraction.

[01:09:25]Okay. So point number one, loss of refraction.

[01:09:32]Loss of refraction loss of refraction.

[01:09:39]So incident ray refra refracted ray normal line. Incident ray incident ray refracted ray normal line lies on the same plane. And coming to the second one, the sign of angle of incidence to sign of angle of refraction equal to constant.

[01:10:03]Sine of angle of incident to s of angle of refraction equal to constant. Once again observe carefully here. So incident refractor normal line. So when light ray is passing from rar to dens bends towards the normal line. We know that. So loss of refraction incident ray refracted ray normal line lies on the same plane. So the ratio of sign of angle of incident to sign of angle of refraction equal to constant that is n.

[01:10:35]So here we can also take absolute refractive index and relative refract index. So n = c by v. So n = c by v that is absolute refractive index. speed of light in vacuum by speed of light in medium. So relative refract index n_sub_21 = n_sub_2 by n_sub_1 that is equal to v_sub_1 by v_sub_2 n12 that is equal to n_sub_1 by n_sub_2 = v_sub_2 by v_sub_1.

[01:11:06]So this is about relative refract index.

[01:11:10]Absolute refract index is nothing but n= c by v. relative refract index n_sub_21 n_sub_2 by n1 = v_sub_1 by v_sub_2 ns12 = n1 by n2= v_sub_2 by v_sub1 understood or not so I hope it is very clear so this is about loss of refraction so and refractive index this is about refractive index understood or not so next one so I'll discuss about Now we'll discuss about light passes through the glass slab how it will be.

[01:12:06]So here I'm taking the glass slab.

[01:12:11]So rarer medium, denser medium, rarer medium and denser medium.

[01:12:19]Light ray is passing from rarer to denser.

[01:12:23]So this the normal line.

[01:12:26]So it is passing from denser to rarer.

[01:12:31]So it moves away from the normal line here like this.

[01:12:35]Okay. So here we are extending the incident ray.

[01:12:40]So the angle between incident ral is called angle of incidence. Angle between refracted ray and normal line is called angle of refraction. Angle between emergent ray and normal is called angle of emergence. And the distance between so the distance between eent ray and extended incident or initial direction of the incident ray is called lateral shift. Lateral shift.

[01:13:09]Lateral shift understood or not? I hope it is very clear. This is about lateral shift. And coming to the next one. So here is a beaker. This the beaker. So I place the coin at the bottom of the beaker. The person is standing over here. So from this from point A you can't able to see the coin after pouring water. So here you can see after pouring water the coin position rises up. So this actual position this one is operent. So actual position of the coin apparent position of the coin. So the distance between actual position to upend position of the coin is called vertical shift. The distance between actual position to append position of the coin is called.

[01:13:58]So this actual position this upend position. So the distance between actual position apparent position is called vertical shift. So even if you're taking the pencil so here you can obser I'm placing the pencil over here. So here like this.

[01:14:16]Okay. At this position so at the interface between air and water. So at this position the pencil appears to be bent. The pencil appears to be bent.

[01:14:28]Understood or not? So due to refraction of light due to refraction of light. So even if you place the lemon inside of the uh glass so the lemon appears bigger due to refraction of light. Due to refraction of light understood or not?

[01:14:48]So I hope it is very clear. So these are the points once again. If the light ray is passing from rad to denser bends towards the normal line. If it is passing from denser to rate it moves away from the normal line. So angle between incident normal line is called angle of incidence. Angle between refractor and normal line is called angle of refraction. Angle between emergent ray and normal line is called angle of emergence. And here emergent ray and initial direction of the incident ray. The distance between emergent ray and initial direction of the incident ray is called lateral shift. And here you can observe so the distance between actual position to append position of the coin is called vertical shift. And here so the pencil is placed in the beaker it appears to be bent and if you place the lemon it appears bigger. Okay. So these are all about refraction of light. These are all about refraction of light. Understood.

[01:15:44]Next one.

[01:16:12]So next one we will discuss about rail rules of convex lens.

[01:16:16]Rail rules of convex lens. I'm taking the convex lens here like this.

[01:16:22]So optic center f_sub_1 to f_sub_1 f_sub_2 to f_sub_2.

[01:16:32]So light ray is coming from minity after refraction passes through focus point number one coming to the point number two. So here you can see optic center f_sub_1 to f_sub_1 f_sub_2 to f_sub_2.

[01:16:59]Okay. So light ray is passing through focus after refraction it will become it become parall to the principal axis.

[01:17:09]parall to the principal axis. And coming to the third one. So here convex lens.

[01:17:17]So optic center f_sub_1 to f_sub_1 f_sub_2 to f_sub_2.

[01:17:27]So light ray is passing through optic center.

[01:17:33]Then no deviation takes place.

[01:17:37]So lighter is passing through par. Light ray is passing parall to the principal axis after refraction passes through focus. Light ray is passing through focus after refraction become parall to the principal axis. Light ray is passing through optic center. No deviation takes place. Understood or not? These are rare rules of convex lens. Rail rules of convex lens. Coming to concave lens.

[01:18:10]Convex concave lens. So these are all about convex lens. So now we'll discuss about concave lens.

[01:18:20]Concave lens.

[01:18:29]So optic center f_sub_1 to f_sub_1 f_sub_2 to f_sub_2.

[01:18:40]Okay. So object is lighter is coming from infinity after reflection.

[01:18:48]So after refraction right after refraction it passes through focus. And coming to the second one.

[01:19:03]So optic center f_sub_1 2 f_sub_1 f_sub_2 2 f_sub_2.

[01:19:13]Okay. So light rays passing through four occurs after refraction become parall to the principal axis.

[01:19:23]Then next so optic center f_sub_1 to f_sub_1 f_sub_2 to f_sub_2. So light ray is passing through optic center.

[01:19:40]No deviation takes place.

[01:19:44]understood or not? So these are three real rules of convex lens and concave lens. And coming to the image formations, image formations by convex lens and concave lens.

[01:20:00]Convex lens and concave lens. Let's discuss about it.

[01:20:06]Let's discuss about it.

[01:20:32]So convex lens optic center f_sub_1 2 f_sub_1 F_sub_1 F_sub_2 to F_sub_2.

[01:20:46]Okay. Now, no object is placed at infinity.

[01:20:53]The object is placed at infinity.

[01:20:56]So, one light I'm taking like this.

[01:20:59]Another light I'm taking. After refraction, those light rays are meeting at f_sub_2.

[01:21:07]Object is at infinity. image is forming at f_sub_2. Nature of the image is real and inverted. Size of the image is highly diminished.

[01:21:17]Okay. And coming to the next one, Arctic center F_sub_1 2 F_sub_1 F_sub_2 2 F_sub_2.

[01:21:32]Okay. So, object is placed.

[01:21:37]Object is placed beyond to f_sub_1. How many light rays are required to form the image of the object? Minimum two light rays are required to form the image of the object. One lighter I'm taking like this. So it passes through focus.

[01:21:52]Another light ray is passing through optic center.

[01:21:58]The image will form between f_sub_1 to f_sub_2.

[01:22:02]Object is placed beyond to f_sub_1.

[01:22:06]beyond to f_sub_1.

[01:22:10]Image is formed between f_sub_2 and to f_sub_2.

[01:22:16]Nature of the image is real and inverted. Size of the image is diminished. Nature of the image is real and inverted. Size of the image is diminished. Understood or not? So I hope it is very clear. Next one.

[01:22:43]So next one object is placed head to f_sub_1.

[01:22:51]So optic center f_sub_1 to f_sub_1 f_sub_2 to f_sub_2.

[01:23:00]Object is placed at F1. One light I'm taking like this. It passes through focus.

[01:23:07]Another light ray is passing through optic center.

[01:23:12]Those light rays will be meeting here.

[01:23:16]Okay. Object is at f_sub_2 f_sub_1.

[01:23:18]Image also will format to f_sub_2.

[01:23:22]Object is placed at f_sub_1. Image also will format to f_sub_2. Nature of the image is real and inverted. size of the image is same size. Okay. So, next one.

[01:23:36]So, object is placed.

[01:23:44]Object is placed in between F_sub_2 to F_sub_2.

[01:23:53]Optic center f_sub_1 to f_sub_1 f_sub_2 to f_sub_2 object is placed between f_sub_1 and f_sub_1 object is placed between f_sub_1 and f_sub_1. So one light I'm taking like this after reflection passes through focus another light is passing through optic center light will be meeting beyond okay object is placed between to f_sub_1 and f_sub_1 image will form beyond to f_sub_2 beond to f_sub_2 nature of the image is real and inverted size of the image is enlarged Nature of the image is real and inverted. Size of the image is enlarged.

[01:24:44]Okay. So this about fourth one. Coming to the fifth one.

[01:24:55]Coming to the fifth one.

[01:25:03]Arctic center f_sub_1 2 f_sub_1 f_sub_2 to f_sub_2 object is placed at f_sub_1 okay so one light I'm taking like this after that passes through focus another lighter is passing through optic center f1 image will form at infinity nature of the image real and inverted size of the image is highly enlarged size of the image is highly enlarged.

[01:25:37]Okay. So coming to the last one, last image formations for convex lens.

[01:25:48]Last image formations for convex lens.

[01:25:52]So do like, share and subscribe to student brand.

[01:25:57]So this the last image formations f_sub_1 2 f_sub_1 f_sub_2 2 f_sub_2 do like share and subscribe to student brand if you like the content if you like the channel if you like my explanation share to your friends click on like button okay so this is the last image formations for convex lens so do support the channel so I'm placing the object between f_sub_1 One light I'm taking like this after that passes through focus another light ray is passing through optic center so if you're extending these light rays those light rays are meeting here so object is placed between f_sub_1 and image is forming same side of the object nature of the image is virtual erect and enlarged nature of the image is virtual erect and enlarged. Okay. So very very important very very important make sure that you are practicing this question twice or thrice.

[01:27:09]And coming to the concave lens so concave lens only two cases are there.

[01:27:16]Concave lens only two cases are there.

[01:27:18]So let's discuss about it. So I'm taking the concave lens. This is a concave lens.

[01:27:26]Okay. Optic center f_sub_1 2 f_sub_1 f_sub_2 to f_sub_2.

[01:27:35]So one light I'm taking like this it reflected back another light I'm taking like this. So if you are explaining here also object is at infinity image is forming at f_sub_1 nature of the image is virtual erect and diminished highly diminished point size image is formed at focus and coming to the next one optic center f_sub_1 2 f_sub_1 f_sub_2 F_sub_2 2 F_sub_2.

[01:28:15]So object is placed here.

[01:28:19]One light ray taking like this.

[01:28:22]Another light ray is passing through optic center.

[01:28:26]The image will form between F_sub_1 and V.

[01:28:30]So object is placed between optic center and infinity. Image will form between F_sub_1 and V. Nature of the image is virtual, erect and diminished. Okay.

[01:28:41]Sign conventions will follow approximate. So as per mirror so in the direction of incident is positive opposite incident is negative of the princip positive below the princip negative. So all measurements will be taken from the optic center here. So lens formula 1x f= 1x v minus 1x u mirror formula sorry magnification height of the image by height of the object v by u and for power of convex lens is positive for power of lens is positive for convex lens power of lens is negative for concave lens the degree of converging or diverging of lens achieved by lens achieved is known as power of lens P equal to 1x F the reciprocal of focal length is called power of lens of power of lens is dapter. So here P equal to 1x F F in meters.

[01:29:30]Okay. So I hope it is very clear. Do like, share and subscribe to student the brand. This is our signing off. If you like the content, if you like the channel, do like, share and subscribe to shooting the brand. Share to your friends. Ask your friends to join to the class. Thank you so much for joining, attending, listening and giving an opportunity to teach. So if you like the end do like, share and subscribe. Share to your friends. Thank you so much.