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. `n lt (1)/(sqrt(2))`
B. `n gt sqrt(2)`
C. `n gt (1)/(sqrt(2))`
D. `n lt sqrt(2)`

Answer

B

Explanation

` i=45^(@) " for TIR" i gt C`
` or sin i gt sin C`
`or sin 45^(@) gt (1)/(n) rArr n gt (1)/(sqrt(2))`