Question

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

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

Answer 1

Answer: (A)

${90}^{\circ }-i$

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