Question

A ray of light incident normally on one face of a right isosceles prism is totally reflected as shown in fig. What must be the minimum value of refractive index of glass?
Give relevant calculations.

Answer 1

We know that light incident normally on one face of right isosceles prism is totally reflected.

$\mu =\frac{1}{sin\left(c\right)}$ (Total internal reflection)

C is a critical angle, which is 45

$\mu =\frac{1}{sin\left(45\right)}$

$\mu =\sqrt{2}$

Thus minimum value of refractive index is 1.414