Question 340: Ray Optics

Question

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

Accepted Answer

For total internal reflection, sini $>$ sinC
where, i = angle of incidence, C = critical angle
But, sinC = ${1 \over \mu }$
$ 	herefore $ sini $>$ ${1 \over \mu }$
$ \Rightarrow $ $\mu $ $>$ ${1 \over {\sin i}}$
$ 	herefore $ $\mu $ $>$ ${1 \over {\sin 45^\circ }}$
$ \Rightarrow $ $\mu $ $>$ $\sqrt 2 $

Answer

$\mu $ = 1.33

Answer

$\mu $ = 1.40

Answer

$\mu $ = 1.50

Answer

$\mu $ = 1.25

Ray Optics

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

Choose the correct answer: