Question

If a transparent material has a refractive of 2.0;
a) calculate the critical angle
b) if the refractive index were less than 2,0, would the critical angle be greater or less than before?

Im super confused at this :(

Answer 1

If a ray of light INSIDE a medium of index N is incident at an angle of A or more upon a surface with index 1.00 outside, the light will be totally reflected. A is called the critical angle. It is given by the equation

sinA = 1/N

(a) In this case, N = 2, so

A = sin^-1 (1/2) = 30 degrees

(b) If N<2,
sin A > 1/2 and A > 30 degrees.

The answer is "greater".

Answer 2

I can't understand how you find that answer