A light ray is incident perpendicularly to one face of a `90^circ` prism and is totally internally reflected at the glass-air interface. If the angle of reflection is `45^circ`, we conclude that the refractive index n

Options

A. Less than `1.41`
B. Equal to `1.41`
C. Greater than `1.41`
D. None of these

Answer

C

Explanation

For total internal reflection `thetagtC`
`impliessin thetagtsin Cimpliessin thetagt(1)/(mu)`
or`mugt(1)/(sin theta)implies mugt(1)/(sin 45^(@))implies mugtsqrt(2)impliesmu gt 1.41`
`impliesmugt1.41`