Question

A ray of light travels in a block of material and exits to the water (n_w = 1.33). The angle of incidence in the block is 55^o . Select the CORRECT value(s) of an index of refraction for the total internal reflection to occur for the ray in the block.

A. 1.3

B. 1.5

C. 1.7

D. 2.4

Answer 1

$$\sin\theta=\frac{n_w}{n}\\\sin 55=\frac{1.33}{n}\\n=1.62$$