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Find those principles, nature displays varieties of events and phenomena, and based on those we have to understand physics. | Find those principles, nature displays varieties of events and phenomena, and based on those we have to understand physics. | en | en_hcverma | neutral | medium | 9.35 | 24,000 | 36.1 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
All our equations, all our formulae, all our derivations are essentially an attempt to understand these basic principles on which nature displays its events. | All our equations, all our formulae, all our derivations are essentially an attempt to understand these basic principles on which nature displays its events. | en | en_hcverma | neutral | medium | 12.8 | 24,000 | 31 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
So we design some of our own experiments so that those rules, those phenomena, those equations, those concepts are understood in a in a better way. So this particular course is | So we design some of our own experiments so that those rules, those phenomena, those equations, those concepts are understood in a better way. So this particular course is | en | en_hcverma | neutral | medium | 15.3 | 24,000 | 35.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Just to show some experiments, simple experiments, self-designed experiments, you can also design and then see how physics is working there and from that. | Just to show some experiments, simple experiments, self-designed experiments, you can also design and then see how physics is working there and from that. | en | en_hcverma | neutral | medium | 13 | 24,000 | 30.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
develop a deeper understanding of physics. So this is about the course. Now, the participants you have registered | Develop a deeper understanding of physics. So this is about the course. Now, the participants you have registered. | en | en_hcverma | neutral | medium | 10.8 | 24,000 | 40.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
So I'm coining a word, you are my physics loving friend. Physics loving friend. So I'll call you P L F. So all my PLFs | So I'm coining a word, you are my physics loving friend. Physics loving friend. So I'll call you pee el eff. So all my pee el effs | en | en_hcverma | happy | medium | 14.6 | 24,000 | 42 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Welcome to this course. I have divided this eight week course in four broad modules, although in experiments you cannot really divide things. All these divisions | Welcome to this course. I have divided this eight week course in four broad modules, although in experiments you cannot really divide things. All these divisions | en | en_hcverma | neutral | medium | 14.55 | 24,000 | 42.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Revisions in chapters is artificial. When you are doing something, then many of the concepts go together in one experiment. But still, broadly I have divided it in four parts. | Revisions in chapters is artificial. When you are doing something, then many of the concepts go together in one experiment. But still, broadly I have divided it in four parts. | en | en_hcverma | neutral | medium | 14.55 | 24,000 | 38.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
that is optics, that will be our first module. and then mechanics and then electricity magnetism and then oscillations and waves. So roughly two weeks on | That is optics, that will be our first module. And then mechanics and then electricity magnetism and then oscillations and waves. So, roughly two weeks on | en | en_hcverma | neutral | medium | 14.4 | 24,000 | 38.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Optics, two weeks on mechanics, two weeks on electricity magnetism, and two weeks on oscillations and waves. So we will start with our first module that is optics, light. | Optics, two weeks on mechanics, two weeks on electricity magnetism, and two weeks on oscillations and waves. So we will start with our first module that is optics, light. | en | en_hcverma | neutral | medium | 13.9 | 24,000 | 41.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Very simple, light, and the day someone comes to this planet and opens eyes, the interaction with light starts. | Very simple, light, and the day someone comes to this planet and opens eyes, the interaction with light starts. | en | en_hcverma | neutral | medium | 14 | 24,000 | 41.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
And after that we experience so many things about light, we learn so many things about light, and then theories are developed and all other phenomena are there. | And after that we experience so many things about light, we learn so many things about light, and then theories are developed and all other phenomena are there. | en | en_hcverma | neutral | medium | 11.5 | 24,000 | 26.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Now what is the first thing that is taught when a chapter on light starts in schools? Perhaps the first thing is light travels in straight lines. | Now what is the first thing that is taught when a chapter on light starts in schools? Perhaps the first thing is light travels in straight lines. | en | en_hcverma | neutral | medium | 13 | 24,000 | 43.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
So, we will also start from that, and how do we know that light travels in straight lines? We can do certain experiments. So, you have a bulb glowing. | So, we will also start from that, and how do we know that light travels in straight lines? We can do certain experiments. So, you have a bulb glowing. | en | en_hcverma | neutral | medium | 14 | 24,000 | 44.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
You can see it. Put some object in between your eyes and the bulb and what happens? I'm not able to see the bulb. Why? This simple experiment tells me. | You can see it. Put some object in between your eyes and the bulb and what happens? I'm not able to see the bulb. Why? This simple experiment tells me. | en | en_hcverma | neutral | medium | 12.8 | 24,000 | 43.6 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
that light travels in straight lines. Light falls on this card, this paper, therefore it is not able to reach my eyes and therefore I am not able to see. | That light travels in straight lines. Light falls on this card, this paper, therefore it is not able to reach my eyes and therefore I am not able to see. | en | en_hcverma | neutral | medium | 13.7 | 24,000 | 39.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
But does light really go in straight lines? We will come to this question. When we say that light travels in straight lines, this is an approximation. | But does light really go in straight lines? We will come to this question. When we say that light travels in straight lines, this is an approximation. | en | en_hcverma | neutral | medium | 13.6 | 24,000 | 39.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
First thing is, we mean a homogeneous medium, transparent homogeneous medium, only then the light travels in straight lines. And | First thing is, we mean a homogeneous medium, transparent homogeneous medium, only then the light travels in straight lines. And | en | en_hcverma | neutral | medium | 11.1 | 24,000 | 39.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
And you know, if the medium changes, the refractive index of medium changes, light can bend. Mirage is one example and many other examples. | And you know, if the medium changes, the refractive index of medium changes, light can bend. Mirage is one example and many other examples. | en | en_hcverma | neutral | medium | 11.1 | 24,000 | 31.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
The approximation, the approximation in which you can represent light by straight line paths is known as | The approximation, the approximation in which you can represent light by straight line paths is known as. | en | en_hcverma | neutral | medium | 12.4 | 24,000 | 44.8 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Ray optics approximation or geometrical optics approximation. In this approximation, light casts shadows. | Ray optics approximation or geometrical optics approximation. In this approximation, light casts shadows. | en | en_hcverma | neutral | medium | 12.5 | 24,000 | 40.8 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
when you walk in sun or under the street lights, you can see your own shadows on the road. So let us make some shadows. Let's do this experiment. Let's make some shadows. So, | When you walk in sun or under the street lights, you can see your own shadows on the road. So, let us make some shadows. Let's do this experiment. Let's make some shadows. So, | en | en_hcverma | neutral | medium | 14.2 | 24,000 | 42.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Again this bulb. Alright, now I will be making shadow of this pen and you watch for the sharpness of the shadow. Look at the shadow. Quite sharp, rectangular. | Again this bulb. Alright, now I will be making shadow of this pen and you watch for the sharpness of the shadow. Look at the shadow. Quite sharp, rectangular. | en | en_hcverma | neutral | medium | 14.7 | 24,000 | 48.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
I'm increasing the distance of pen from the wall and see how the sharpness is changing. It is quite diffused now, very diffused. Very diffused. If I go close to the wall, | I am increasing the distance of pen from the wall and see how the sharpness is changing. It is quite diffused now, very diffused. Very diffused. If I go close to the wall, | en | en_hcverma | neutral | medium | 15.1 | 24,000 | 45.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
It's quite sharp, rectangular. If I go away from the wall, then it is a totally diffused kind of shadow. Now it will be your task. | It's quite sharp, rectangular. If I go away from the wall, then it is a totally diffused kind of shadow. Now it will be your task. | en | en_hcverma | neutral | medium | 13.5 | 24,000 | 41.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
To explain all these phenomena, this intensity, this diffuseness in terms of | To explain all these phenomena, this intensity, this diffuseness in terms of | en | en_hcverma | neutral | medium | 9.1 | 24,000 | 45 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
the path of light rays or straight line paths that light takes. One more observation, keenly watch. I am rotating this bulb now. | The path of light rays or straight line paths that light takes. One more observation, keenly watch. I am rotating this bulb now. | en | en_hcverma | neutral | medium | 13.8 | 24,000 | 46.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
The shadow is very, very diffused. I am rotating the bulb and you see what happens to the shadow. | The shadow is very very diffused. I am rotating the bulb and you see what happens to the shadow. | en | en_hcverma | neutral | medium | 9.1 | 24,000 | 46.1 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
See how the shadow is changing. I have rotated it almost 90 degrees. Go back. And this is the shadow. | See how the shadow is changing. I have rotated it almost Ninety degrees. Go back. And this is the shadow. | en | en_hcverma | neutral | medium | 15 | 24,000 | 41.1 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Rotate it, rotate the bulb. And this is the shadow. So, this also you have to explain why the | Rotate it, rotate the bulb. And this is the shadow. So, this also you have to explain why the | en | en_hcverma | neutral | medium | 12 | 24,000 | 42.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Shadow is changing its character when the light bulb is getting rotated. Now to give you a clue, I will show you the bulb. | Shadow is changing its character when the light bulb is getting rotated. Now to give you a clue, I will show you the bulb. | en | en_hcverma | neutral | medium | 13.7 | 24,000 | 43.1 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
And you see what happens when the bulb is rotating. Look at the bulb. It's a structure inside this glass. | And you see what happens when the bulb is rotating. Look at the bulb. It is a structure inside this glass. | en | en_hcverma | neutral | medium | 12.2 | 24,000 | 43.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Now this is the initial condition. And now I will be rotating it through 90 degrees. So I'm starting the rotation. So just watch. | Now this is the initial condition. And now I will be rotating it through ninety degrees. So I'm starting the rotation. So just watch. | en | en_hcverma | neutral | medium | 15.1 | 24,000 | 40 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
What kind of changes you see? I've almost rotated it by 90 degrees. Going back. | What kind of changes you see? I've almost rotated it by ninety degrees. Going back. | en | en_hcverma | neutral | medium | 7.9 | 24,000 | 39.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Okay? So I hope this helps in explaining what happened to the shadow with rotation of bulb. So I have this cardboard and in this cardboard I have | Okay? So I hope this helps in explaining what happened to the shadow with rotation of bulb. So I have this cardboard and in this cardboard I have | en | en_hcverma | neutral | medium | 14.2 | 24,000 | 40.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
made a hole. And if you see the shape of the hole, it is in the shape of this sign of plus. The intention is I'll | Made a hole. And if you see the shape of the hole, it is in the shape of this sign of plus. The intention is I'll | en | en_hcverma | neutral | medium | 15.3 | 24,000 | 37.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Let sunlight pass through this hole, this opening, and on the other side, I'll collect that light and see the pattern that light makes. | Let sunlight pass through this hole, this opening, and on the other side, I will collect that light and see the pattern that light makes. | en | en_hcverma | neutral | medium | 10.9 | 24,000 | 36 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Similarly, I will have more cardboard boards with different shapes. Okay, so Ranjit is holding the screen and sunlight is passing through this hole and on the other side it is going. | Similarly, I will have more cardboard boards with different shapes. Okay, so Ranjit is holding the screen and sunlight is passing through this hole and on the other side it is going. | en | en_hcverma | neutral | medium | 14.2 | 24,000 | 39.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
and making a pattern on the screen. And as expected, the pattern made by the light on the screen is also in the shape of that mathematical plus sign. | And making a pattern on the screen. And as expected, the pattern made by the light on the screen is also in the shape of that mathematical plus sign. | en | en_hcverma | neutral | medium | 11.7 | 24,000 | 39.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Now see what happens if the screen is taken away from this opening. So Ranjit is taking the screen away. You can see that the boundaries are diffusing. | Now see what happens if the screen is taken away from this opening. So Ranjit is taking the screen away. You can see that the boundaries are diffusing. | en | en_hcverma | neutral | medium | 13.2 | 24,000 | 38.8 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
And by now it is difficult to recognize that there was a plus shape. And now you can see at this distance, it is almost a circular disc. | And by now it is difficult to recognize that there was a plus shape. And now you can see at this distance, it is almost a circular disc. | en | en_hcverma | neutral | medium | 13.3 | 24,000 | 39.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
The opening is in the shape of plus sign. But the light that falls on the screen going through this same opening is making a circular disk on the screen. | The opening is in the shape of plus sign. but the light that falls on the screen going through this same opening is making a circular disk on the screen. | en | en_hcverma | neutral | medium | 13.9 | 24,000 | 39.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Let us change the shape of the opening. This opening is diamond type, parallelogram. And if you see on the screen, you have that diamond shaped spot. | Let us change the shape of the opening. This opening is diamond type, parallelogram. And if you see on the screen, you have that diamond shaped spot. | en | en_hcverma | neutral | medium | 15.2 | 24,000 | 39 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
And now Ranjit take away the screen. Increase the distance. And you see you don't recognize anymore. | And now, Ranjit, take away the screen. Increase the distance. And you see you don't recognize anymore. | en | en_hcverma | neutral | medium | 11.8 | 24,000 | 39.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
That parallelogram type, diamond type shape, and once again it has become a circular disc. One more shape? | That parallelogram type, diamond type shape, and once again it has become a circular disc. One more shape? | en | en_hcverma | neutral | medium | 11.6 | 24,000 | 41.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
This you can see it's a kind of a rectangle. Nearly rectangular shape of the opening and nearly rectangular shape of the pattern made on the screen by light passing through this rectangular opening. | This you can see it's a kind of a rectangle. Nearly rectangular shape of the opening and nearly rectangular shape of the pattern made on the screen by light passing through this rectangular opening. | en | en_hcverma | neutral | medium | 14.7 | 24,000 | 38.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Now take the screen away. Okay, still you can see it is rectangle. Boundaries are diffusing. | Now take the screen away. Okay, still you can see it is rectangle. Boundaries are diffusing. | en | en_hcverma | neutral | medium | 11.2 | 24,000 | 38.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
And by now it has become a circular disk. You can see the periphery of that spot, it's circular. So independent of the shape of the opening. | And by now it has become a circular disk. You can see the periphery of that spot, it's circular. So independent of the shape of the opening. | en | en_hcverma | neutral | medium | 13.4 | 24,000 | 37.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Your final spot is bright circular disk. So, why the that spot becomes circular? | Your final spot is bright circular disk. So, why the that spot becomes circular? | en | en_hcverma | neutral | medium | 14.2 | 24,000 | 43.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Once the distance between the screen and the opening is large, independent of what is the shape of opening, that bright circular disk is in fact image of the sun. | Once the distance between the screen and the opening is large, independent of the shape of the opening, that bright circular disk is in fact image of the sun. | en | en_hcverma | neutral | medium | 13 | 24,000 | 37.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
The sun's disk is circular, and therefore this is also circular. But when you bring this screen closer to this opening, then it is the opening that decides what kind of shape will be there of the brightest spot. | The sun's disk is circular, and therefore this is also circular. But when you bring this screen closer to this opening, then it is the opening that decides what kind of shape will be there of the brightest spot. | en | en_hcverma | neutral | medium | 14.4 | 24,000 | 37.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
You can understand it if you do little bit of drawing. Suppose in the in that opening, you only have a single point opening, what will happen? Wherever you place your screen, | You can understand it if you do little bit of drawing. Suppose in the in that opening, you only have a single point opening, what will happen? Wherever you place your screen, | en | en_hcverma | neutral | medium | 14.3 | 24,000 | 38.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
That sun, that disk will be imaged as a circular disk here at all distances if it is a single point opening. | That sun, that disk will be imaged as a circular disk here at all distances if it is a single point opening. | en | en_hcverma | neutral | medium | 9.3 | 24,000 | 36.8 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
a actual opening can be thought of as a collection of the single point openings. And therefore each of this point will make a circle. Now if the screen is closed | a actual opening can be thought of as a collection of the single point openings. And therefore each of this point will make a circle. Now if the screen is closed | en | en_hcverma | neutral | medium | 14.8 | 24,000 | 41.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
All these circles are small small circles. Suppose these are the suppose your opening is triangular. So, these are the points which are | All these circles are small small circles. Suppose these are the suppose your opening is triangular. So, these are the points which are | en | en_hcverma | neutral | medium | 15.3 | 24,000 | 45.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
You take these as the points. This is all triangular. Each point is making a circular disk. | You take these as the points. This is all triangular. Each point is making a circular disk. | en | en_hcverma | neutral | medium | 10.2 | 24,000 | 46 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
But if the screen is closed, those discs are small. So you have a disc like this, you have a disc like this, you have a disc like this, you have a disc like this, disc like this and so on. So all this will be there. | But if the screen is closed, those discs are small. So you have a disc like this, you have a disc like this, you have a disc like this, you have a disc like this, disc like this and so on. So all this will be there. | en | en_hcverma | neutral | medium | 12.9 | 24,000 | 36.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
From each point, you make circular discs. But then that triangular shape is still maintained. That triangular shape is still maintained. | From each point, you make circular discs. But then that triangular shape is still maintained. That triangular shape is still maintained. | en | en_hcverma | neutral | medium | 12.2 | 24,000 | 40.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
But if the screen is away and these circles becomes large, then if you make that drawing, you have centers here. | But if the screen is away and these circles becomes large, then if you make that drawing, you have centers here. | en | en_hcverma | neutral | medium | 10.5 | 24,000 | 40.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
You have centers here, but then you are drawing large circles. You are drawing large circles. Like this. From these, what you will see is a round thing, a circular thing. | You have centers here, but then you are drawing large circles. You are drawing large circles. Like this. From these, what you will see is a round thing, a circular thing. | en | en_hcverma | neutral | medium | 15.2 | 24,000 | 40.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
So here, it will be essentially the image of the source, and here, it will be essentially image of the opening. Okay, now I will make shadow. | So here, it will be essentially the image of the source, and here, it will be essentially image of the opening. Okay, now I will make shadow. | en | en_hcverma | neutral | medium | 13.3 | 24,000 | 43 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
using a different light source. This is a laser light source and green light is emitted and is going on the wall. The size of the beam is small. | Using a different light source. This is a laser light source and green light is emitted and is going on the wall. The size of the beam is small. | en | en_hcverma | neutral | medium | 12.6 | 24,000 | 40.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
From the spot on the wall you can see how much is the size, or you can see it somewhere here. So this is the size. And the obstacle that I am bringing | From the spot on the wall you can see how much is the size, or you can see it somewhere here. So this is the size. And the obstacle that I am bringing. | en | en_hcverma | neutral | medium | 13 | 24,000 | 43.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
is much wider than the size of the beam. This is opaque. So if light goes in straight lines, then the whole beam will fall on this. | Is much wider than the size of the beam. This is opaque. So if light goes in straight lines, then the whole beam will fall on this. | en | en_hcverma | neutral | medium | 12.3 | 24,000 | 42.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
object, opaque object, and nothing will go there. So let's see. Here it is. | Object, opaque object, and nothing will go there. So let's see. Here it is. | en | en_hcverma | neutral | medium | 11 | 24,000 | 44.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
The entire light is now falling on this object, opaque object, and everything is blocked and nothing goes on the wall. So light does travel in straight lines. Now I will do something else. We will put an object | The entire light is now falling on this object, opaque object, and everything is blocked and nothing goes on the wall. So light does travel in straight lines. Now I will do something else. We will put an object | en | en_hcverma | neutral | medium | 14.9 | 24,000 | 40.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
which size is less than the diameter of this beam. Now we will be putting a thin wire. | which size is less than the diameter of this beam. Now we will be putting a thin wire. | en | en_hcverma | neutral | medium | 7.4 | 24,000 | 46.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
in front of this light beam. So and it will be thin. So it will not block the whole of the light, only the light which falls on the that thin wire should be blocked and other light should pass and you can expect the shadow of wire. | In front of this light beam. So and it will be thin. So it will not block the whole of the light, only the light which falls on the that thin wire should be blocked and other light should pass and you can expect the shadow of wire. | en | en_hcverma | neutral | medium | 16.9 | 24,000 | 39.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
So we have fixed thin wire on this CD disk and carefully see the central hole. | So we have fixed thin wire on this compact disc and carefully see the central hole. | en | en_hcverma | neutral | medium | 11.1 | 24,000 | 46.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
On the vertical diameter of the central hole, you can see the wire. And our plan is to send this light beam. | On the vertical diameter of the central hole, you can see the wire. and our plan is to send this light beam. | en | en_hcverma | neutral | medium | 14.5 | 24,000 | 46.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
on this wire. So from the sides light will go and apparently perhaps we can expect that light will be blocked by this wire and a shadow will form on the other side. | on this wire. So from the sides light will go and apparently perhaps we can expect that light will be blocked by this wire and a shadow will form on the other side. | en | en_hcverma | neutral | medium | 14.3 | 24,000 | 44.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
So I'll request Ranjit, my associate, to fix up this wire and this light source on some stand so that light falls on this wire. | So I'll request Ranjit, my associate, to fix up this wire and this light source on some stand so that light falls on this wire. | en | en_hcverma | neutral | medium | 12 | 24,000 | 40.7 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
This is the point directly in front of the wire. And wire is opaque, doesn't allow light to pass through. So light should have been stopped there at the wire. And here you should have gotten a dark. | This is the point directly in front of the wire. And wire is opaque, doesn't allow light to pass through. So light should have been stopped there at the wire. And here you should have gotten a dark. | en | en_hcverma | neutral | medium | 14.7 | 24,000 | 44 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
But you have maximum intensity here. And then you see one, two, three on left side, one, two, three on right side, you can keep on counting. There are different zones of | But you have maximum intensity here. And then you see one, two, three on left side, one, two, three on right side, you can keep on counting. There are different zones of | en | en_hcverma | neutral | medium | 13.3 | 24,000 | 42.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
high intensity and then low intensity, again high intensity, again low intensity and so on on left of this bright spot at the center and right of the bright spot of the center. So this is the shadow of | high intensity and then low intensity, again high intensity, again low intensity and so on on left of this bright spot at the center and right of the bright spot of the center. So this is the shadow of | en | en_hcverma | neutral | medium | 15.1 | 24,000 | 36.8 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
a thin wire. So what happened? When we used a pen, a pencil, varieties of objects in front of a light beam. | A thin wire. So what happened? When we used a pen, a pencil, varieties of objects in front of a light beam. | en | en_hcverma | neutral | medium | 13.5 | 24,000 | 43.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
Light was partially blocked by the object and there was a darkness in front of that object. But here the things are very very different. Light | Light was partially blocked by the object and there was a darkness in front of that object. But here the things are very very different. Light | en | en_hcverma | serious | medium | 12.6 | 24,000 | 44.1 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
does not go in straight line paths in this particular experiment. So when does light go in straight line paths? In what conditions I cannot use this approximation? | Does not go in straight line paths in this particular experiment. So, when does light go in straight line paths? In what conditions I cannot use this approximation? | en | en_hcverma | neutral | medium | 12.7 | 24,000 | 40.9 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
For that, you also know that light is a wave. And there is something called wavelength of light. So, the openings or obstacles... | For that, you also know that light is a wave. And there is something called wavelength of light. So, the openings or obstacles... | en | en_hcverma | neutral | medium | 12.4 | 24,000 | 43.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
size of these openings and obstacles and the wavelength. They will decide whether light can be treated as rays going in straight lines. | size of these openings and obstacles and the wavelength. They will decide whether light can be treated as rays going in straight lines. | en | en_hcverma | neutral | medium | 13 | 24,000 | 42.3 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
and stopping wherever an opaque object is encountered or light will show some other character. And the rule is that if the size of the opening or obstacle | and stopping wherever an opaque object is encountered or light will show some other character. And the rule is that if the size of the opening or obstacle | en | en_hcverma | neutral | medium | 14.9 | 24,000 | 42.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
is much much larger than the wavelength. 100 times, 1000 times, 10,000 times, 100,000 times. Then you can treat this light as | Is much much larger than the wavelength. One hundred times, one thousand times, ten thousand times, one hundred thousand times. Then you can treat this light as. | en | en_hcverma | neutral | medium | 11.4 | 24,000 | 38.2 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
as rays going in straight lines and those straight lines you call rays. and we call this approximation as ray optics approximation. and that was the case when I used bigger objects. | As rays going in straight lines and those straight lines you call rays. And we call this approximation as ray optics approximation. And that was the case when I used bigger objects. | en | en_hcverma | neutral | medium | 15.3 | 24,000 | 35.5 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
to form shadows. But if the size of the opening or the obstacle is comparable to the wavelength of light, 10 times, 15 times, 20 times, maybe. | To form shadows. But if the size of the opening or the obstacle is comparable to the wavelength of light, ten times, fifteen times, twenty times, maybe. | en | en_hcverma | neutral | medium | 14.55 | 24,000 | 43.4 | -23 | en_01 | https://www.youtube.com/watch?v=bALYnO_HvII | standard-youtube | |
And this approximation is known as geometrical ray approximation. And optics discussed under this proposition is called geometrical optics. | And this approximation is known as geometrical ray approximation. And optics discussed under this proposition is called geometrical optics. | en | en_hcverma | neutral | medium | 13.2 | 24,000 | 38.4 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
So, in this situation you can assume that light travels in straight lines in a homogeneous medium until there is some obstacle or some reflector or some medium change or something. It goes in a straight line. | So, in this situation you can assume that light travels in straight lines in a homogeneous medium until there is some obstacle or some reflector or some medium change or something. It goes in a straight line. | en | en_hcverma | neutral | medium | 15.1 | 24,000 | 31.2 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
which you call light ray. It's also called ray approximation. Now in this ray approximation, the basic assumption is light goes in straight line in a homogeneous medium. | which you call light ray. It's also called ray approximation. Now in this ray approximation, the basic assumption is light goes in straight line in a homogeneous medium. | en | en_hcverma | neutral | medium | 13.9 | 24,000 | 42.3 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
That we can see in our experiments also. Now, light goes in a straight line in a homogeneous medium. | That we can see in our experiments also. Now, light goes in a straight line in a homogeneous medium. | en | en_hcverma | neutral | medium | 9.1 | 24,000 | 45.2 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
can be explained, understood just by symmetry of the space. Our space | Can be explained, understood just by symmetry of the space. Our space. | en | en_hcverma | neutral | medium | 8.1 | 24,000 | 40.7 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
which I call homogeneous, isotropic, unless there is a material and that material has varying properties in varying positions or in varying directions, if that be the case then it's a different story. | Which I call homogeneous, isotropic, unless there is a material and that material has varying properties in varying positions or in varying directions, if that be the case then it's a different story. | en | en_hcverma | neutral | medium | 13.9 | 24,000 | 29 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
But it's a truly homogeneous isotropic medium or vacuum. And light is going in some direction at some point. Then if it has to bend... | But it's a truly homogeneous isotropic medium or vacuum. And light is going in some direction at some point. Then if it has to bend... | en | en_hcverma | neutral | medium | 14.6 | 24,000 | 47.7 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
In which direction it will bend? All directions are equal, equivalent. Suppose light is going like this in two dimensional plane, let me talk. So light is going like this at some instant. | In which direction it will bend? All directions are equal, equivalent. Suppose light is going like this in two dimensional plane, let me talk. So light is going like this at some instant. | en | en_hcverma | neutral | medium | 11.8 | 24,000 | 46.5 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
And now it has to bend. Suppose it doesn't go in straight line. It's all homogeneous medium. Should it bend this way? Or should it bend this way? All directions are equivalent. | And now it has to bend. Suppose it doesn't go in straight line. It's all homogeneous medium. Should it bend this way? Or should it bend this way? All directions are equivalent. | en | en_hcverma | neutral | medium | 11.2 | 24,000 | 45.1 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
All positions are equivalent, is the same medium everywhere, and the medium is isotropic. Isotropic means all directions are same. So if it is going at certain instant in this direction, should it move this way? | All positions are equivalent, is the same medium everywhere, and the medium is isotropic. Isotropic means all directions are same. So if it is going at certain instant in this direction, should it move this way? | en | en_hcverma | neutral | medium | 13.8 | 24,000 | 35.6 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
Should it move this way? How does it choose between these two if the medium is same? | Should it move this way? How does it choose between these two if the medium is same? | en | en_hcverma | neutral | medium | 6.3 | 24,000 | 46.7 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
or similarly if you go out of this plane, you can have a bent like that, bent like that, so many bending directions you can make. It cannot. So it must continue in this direction. So it must go in straight lines. | Or similarly if you go out of this plane, you can have a bent like that, bent like that, so many bending directions you can make. It cannot. So it must continue in this direction. So it must go in straight lines. | en | en_hcverma | neutral | medium | 14.6 | 24,000 | 42.3 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
So many of the physics phenomena can be explained just on the basis of symmetry of space, of medium and so on and this is one of them. | So many of the physics phenomena can be explained just on the basis of symmetry of space, of medium and so on and this is one of them. | en | en_hcverma | neutral | medium | 12.9 | 24,000 | 38.2 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
Now, light going in straight lines has a different aspect, interesting aspect. Suppose I have a point A, and suppose I have a point B. | Now, light going in straight lines has a different aspect, interesting aspect. Suppose I have a point A, and suppose I have a point B. | en | en_hcverma | neutral | medium | 9 | 24,000 | 37.9 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
And the medium is homogeneous isotropic. So I say that light will take path from A to B which will be straight line path. | And the medium is homogeneous isotropic. So I say that light will take path from A to B which will be straight line path. | en | en_hcverma | neutral | medium | 11.2 | 24,000 | 101.3 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube | |
it will go like this, not like this, or not like this, and so on. Okay, so these paths are not allowed. This path, light takes this path. | It will go like this, not like this, or not like this, and so on. Okay, so these paths are not allowed. This path, light takes this path. | en | en_hcverma | neutral | medium | 11.2 | 24,000 | 41.2 | -23 | en_02 | https://www.youtube.com/watch?v=woGREVliFsA | standard-youtube |
End of preview. Expand in Data Studio
🎙️ Vaani: Curated Indian-English + Hindi Speech Corpus
A small, hand-curated single-speaker speech corpus (~62 minutes, 285 clips) for expressive Text-to-Speech. Real Indian voices, accurate transcripts, and emotion tags reviewed by ear.
Built as a data-quality and curation exercise: the pipeline is simple by design; the real work is in the listening, correcting, and selecting.
✨ Highlights
- 🗣️ Two real Indian speakers, one consistent voice per language. No synthetic / AI narration.
- 🎧 Clean, studio-grade audio (no background music), verified with VAD and diarization.
- 📝 Two transcripts per clip: verbatim and TTS-normalized.
- 🎭 Emotion / style tags across 8 categories.
- 🔎 Full provenance: every clip carries its
source_urlandlicense.
📊 Composition
| Language | Code | Clips | Minutes |
|---|---|---|---|
| Indian English | en |
146 | 30.7 |
| Hindi | hi |
139 | 31.6 |
| Property | Value |
|---|---|
| Sample rate | 24 kHz, mono, 16-bit WAV |
| Loudness | -23 LUFS (EBU R128), true-peak ≤ -1 dBFS |
| Clip length | 4 to 20 s, sentence-bounded |
| Speakers | one voice per language (speaker_id) |
🗣️ Speakers
| Language | Speaker | Style |
|---|---|---|
| Indian English | Prof. H.C. Verma | clear, expressive physics lectures |
| Hindi | Kahani Suno | dramatic Premchand literary narration |
🎭 Emotion distribution
| Emotion | Clips |
|---|---|
neutral |
181 |
serious |
53 |
angry |
23 |
sad |
20 |
happy |
4 |
calm |
3 |
excited |
1 |
🧾 Data fields
| Field | Description |
|---|---|
audio |
24 kHz mono waveform |
text |
verbatim transcript (human-corrected) |
normalized_text |
TTS-ready (numbers / abbreviations expanded) |
language |
en or hi |
speaker_id |
consistent per-language speaker |
emotion, intensity |
style tag and its intensity |
duration_sec, snr_db, lufs, sample_rate |
per-clip audio metrics |
source_url, license |
provenance |
🚀 Usage
from datasets import load_dataset
ds = load_dataset("ghostieee11/vaani-speech-corpus", split="train")
ex = ds[0]
print(ex["text"], "|", ex["emotion"])
audio = ex["audio"] # decoded waveform and sampling rate
🛠️ How it was built
YouTube audio (yt-dlp) -> ffmpeg standardize (24 kHz mono) -> Sarvam
diarization single-speaker check -> Silero-VAD segmentation -> Sarvam ASR
(saaras:v3) drafts -> human listening, correction and emotion tagging ->
Sarvam LLM text normalization -> automated QC gates (SNR, loudness, peak,
bandwidth, duration). Full pipeline and curation log are in the GitHub repository.
📄 Licensing and provenance
Audio is sourced from YouTube for research and educational use. Every clip
records its source_url, creator and license. The sources are under YouTube's
standard license (not Creative Commons); curation prioritised audio quality
(clean, single, real-human Indian voices) over license filtering. This dataset
claims no ownership of the source audio and will honour any removal request.
⚠️ Limitations
Small corpus, built to demonstrate curation quality rather than scale. Emotion coverage reflects the chosen speakers (the English physics lectures skew neutral). Emotion labels are subjective guidance, not ground truth. Not validated for production training.
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