00:01
In this question we have a triangular glass prism of refractive index and it has an apex angle of phi.
00:09
We want to find the smallest angle of incidence so that light can still emerge from the prism.
00:19
So here i've drawn some red, like the rays, light rays, travels from the left side, enters the prism, enters the prism, from the left phase with incident angle of incidence data i and then it has to go out so for the smallest angle data i okay you would hit the right phase at the critical angle okay so like alpha would be the critical angle of the prism okay the reason is that only then um your uh the ray that emerge will be parallel to the right phase.
01:10
So that's the reason why the smallest angle of incidents will give critical angle over here.
01:22
All right, so given that refractive index equals to n, we have the critical angle, sign, data c is equal to 1 over n okay and then alpha equals to data c is equal to axi 1 over n k okay then next we'll examine this diagram for a while we also have snows law okay let's say is that and side data i is equal to and sign data r.
02:09
Okay, now the air has refractive index 1.
02:13
So, it's now slow will give us sign data i equals 2 and sign data r...