A ray of light in incident on a glass sphere of refractive index `3//2`. What should be the angle of incidence so that the ray which enters the sphere does not come out of the sphere ?

Options

A. `tan^(-1)(2//3)`
B. `60^(@)`
C. `90^(@)`
D. `30^(@)`

Answer

C

Explanation

`/_ABO=/_OAB=theta_(C)`
`sin theta_(c)=(1)/(mu)=(2)/(3)`
Applying Snell,s law at `A,(sin i)/(sin theta_(theta))=(3)/(2)`
`sin i=((3)/(2))((2)/(3))=1`
or `i=90^(@)`