When a ray of light enter from one medium to another, its velocity is doubled. The critical angle for the ray for two internal reflection will be

Options

A. `30^(@)`
B. `60^(@)`
C. `90^(@)`
D. Informatino is incomplete

Answer

C

Explanation

`mu=(1)/(sini_(c))=(v_(1))/(v_(2))=(2v_(2))/(v_(2))=2,sini_(c)=(1)/(2)thereforei_(c)=30^(@)`