Question

A beam of light is incident on a glass slab $(\mu =1.54)$ in a direction as shown in the figure. The reflected light is analysed by a polaroid prism. On rotating the polaroid (take, tan ${57}^0$ = 1.54).

Answer 1

Because $\mu$ = 1.53

and i = ${57}^0$

tan ${57}^0$ = 1.53 = $\mu$

$\theta ={57}^0$ is angle of polarisation.

Hence by brewster' law reflected ray will be plane polarised.

so, on rotating polaroid intensity decreases to zero and again increases