Question

A ray of light exits from a material with a refractive index of 1.75, traveling into air. The angle of refraction is 25°. What was the original angle of incidence?​

Answer 1

Answer:

θi = 47.7°

Explanation:

The formula for the refractive index is as follows:

$n = \frac{Sin\theta_i}{Sin\theta_r}$

where,

n = refractive index = 1.75

θi = angle of incidence = ?

θr = angle of refraction = 25°

Therefore,

$1.75 = \frac{Sin\ \theta_i}{Sin\ 25^o} \\\\(1.75)(Sin\ \ 25^o) = Sin\ \theta_i\\\\\theta_i = Sin^{-1}(0.739)$

θi = 47.7°