Question

Light is incident at an angle $i$ on a glass slab. The reflected ray is completely polarised. The angle of refraction is

• A. $90^{°}-i$
• B. $180^{°}-i$
• C. $90^{°}+i$
• D. $i$

Answer 1

Answer: (A)

Brewster discovered that when a beam of unpolarised light is reflected from a transparent medium (refractive index $=\mu$ ), the reflected light is completely plane polarised at a certain angle of incidence (called the angle of polarisation $i)$

From figure it is clear that $i+r=90^{\circ }$
$r=(90-i)$