Question 392: 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 45o. 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 45o. For which of the following value of \mu $ the ray can undergo total internal reflection ?

Choose the correct answer: