Question

At polarising angle, the angle between the reflected ray and refracted ray from a surface _______.

Answer 1

${90}^o$.

The polarization angle ( also called Brewster's angle)is defined as the angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection.

Brewster's Law states that the tangent of the angle of polarization is numerically equal to the refractive index of the medium.

$\mu$ = tan i ...................... (1)

From Snell's law:

$\mu$ = $\frac{sini}{sinr}$ ....................(2)

Comparing (1) and (2)

cos i = sin r = cos ($\frac{\pi }{2}$ - r)

i.e. i = ($\frac{\pi }{2}$ - r)

So, i + r = $\frac{\pi }{2}$

So, as seen from the diagram, if i + r = ${90}^o$ Then the angle between reflected ray and refracted ray will be ${180}^o$ - ${90}^o$ = ${90}^o$