00:01
In this question, it is about total internal reflection.
00:05
So now we have a glass fiber, so much inside water.
00:15
So yeah, so much inside.
00:19
So outside is water.
00:22
Here you have glass.
00:25
So in the glass, the refractive index is 1 .5.
00:31
For water the refractive index is 1 .3 we want to find a 1 .33 we want to find a critical angle such that the light stays inside the fiber so which means that we want light ray 2 to stay inside like this okay so the critical angle will be such that okay at critical angle.
01:15
Okay, so what happens is that this water, this glass, what happens is that you want the light ray to hit the interface, and then it goes 90 degrees, so data c, and then here 90 degrees, so this is what we want to get...