00:01
All right, so we have a fiber optic cable, which we are producing a curve in, and the width of this fiber optic cable is d.
00:07
And what we want to know is what is the minimum radius that this curve can have, the outside radius, basically, that this curve can have so that light can still be transmitted down the cable.
00:19
And so light is coming in in this direction.
00:22
And so if we follow these paths of light, the light that is most likely to be reflected as a light.
00:30
The light sort of along the innermost region because as it travels through the fiber, it's going to strike the interface at this point and this angle of incidents we can get from kind of drawing an angle between, it's called this angle theta, between the normal surface and the, let's see, the center of this curve.
00:55
So if i do this correctly, i have to bear with me while i get my lines working.
01:03
So this is.
01:04
Is about where our angle of incidence is going to be.
01:07
And you can see that we have basically a triangle here with the hypotenuse length of r.
01:15
And then this side length is going to be r minus d, like the bottom length.
01:22
And so this angle theta is our angle of incidence.
01:25
We want this to be equal to the critical angle.
01:27
And we know the critical angle or something is going to be like 1 over n, where n is the index of refraction of the fiber optic cable...