A ray of light travelling in a transparent medium falls on a surface separating the medium from air at an angle of incidence of 45 degree. The ray undergoes total internal reflection. If n is the refractive index of the medium with respect to air, select the possible value (s) of n from the following:

Options

A. 1.3
B. 1.4
C. 1.5
D. 1.2

Answer

C,D

Explanation

For total internal reflection to take place :
Angle of incidence , i`gt "critical angle " , theta_(C)`
`implies "sini" gt "sin" theta_(C)`
`implies "sin" 45^(@) gt (1)/(n)`
`implies (1)/(sqrt(2)) gt (1)/(n)`
`implies n lt sqrt(2) implies n gt 1.414`
Therefore , possible values of n can be `1.5` or `1.6` in the given options .