Question

When the angle of incidence on a material is 60$^{\circ}$, the reflected light is completely polarized. The velocity of the refracted ray inside the material is (in $ms^{-1}$)

• A. $3 \times 10^8$
• B. $\bigg[\frac{3}{\sqrt2}\bigg] \times 10^8$
• C. $\sqrt3 \times 10^8$
• D. $0.5 \times 10^8$

Answer 1

Answer: (C)

$\sqrt3 \times 10^8$

Answer 2

From Brewster's law, $\mu = tan \, i_p$
$\Rightarrow \frac{c}{v} = tan \, 60^\circ = \sqrt3$
$\Rightarrow v = \frac{c}{\sqrt3} = \frac{3 \times 10^8}{\sqrt3}$
$= \sqrt3 \times 10^8 \, ms^{-1}$