A ray of light travelling in a transparent medium f refractive index `mu`, falls on a surface separating the medium from air at an angle of incidence of `45^(@)`. For which of the following value of `mu` the ray can undergo total internal reflection ?

Options

A. `mu = 1.33`
B. `mu = 1.40`
C. `mu = 1.50`
D. `mu = 1.25`

Answer

C

Explanation

For total internal reflection,
`sini gt sin C`
where, i = angle of incidence,C = critical angle
But, `sinC = (1)/(mu) :. sini gt (1)/(mu)` or `mu gt (1)/(sini)`
`:. mu gt (1)/(sin45^(@))` or `mu gt sqrt(2)` , (`I = 45^(@)` (Given))
Hence, option (c) is correct.