Question

When the angle of incidence on a material is ${60}^o$, the reflected light is completely polarised. The velocity of the refracted ray inside the material is

• A. $3\times {10}^8$
• B. $\frac{3}{\sqrt{2}}\times {10}^8$
• C. $\sqrt{3}\times {10}^8$
• D. $0.5\times {10}^8$

Answer 1

The correct option is C $\sqrt{3}\times {10}^8$

From Brewster's law
$\mu =\tan i_p$
$\Rightarrow$ $\frac{c}{v}=\tan {60}^o$
$=\sqrt{3}$
$\Rightarrow$ $v=\frac{c}{\sqrt{3}}$
$=\frac{3\times {10}^8}{\sqrt{3}}=\sqrt{3}\times {10}^{8}m/s$