A ray of light travelling through rarer medium is incident at very small angle i on a glass slab and after refraction its velocity is reduced by 20%. The angle of deviation

Options

A. `i/8`
B. `i/5`
C. `i/2`
D. `(4i)/5`

Answer

B

Explanation

According to question, at glass-air interface velocity is reduced by 20% of the velocity of light.
So, deviation =20% of I
= `(20xx i)/(100)=(i)/(5)`