Question

Unpolarised light is incident from air on a plane surface of a material of refractive index $'\mu'$. At a particular angle of incidence $'i'$, it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation ?

• A. $ i = \tan^{-1} (\frac{1}{\mu})$
• B. Reflected light is polarised with its electric vector parallel to the plane of incidence
• C. $ i = \sin^{-1} (\frac{1}{\mu})$
• D. Reflected light is polarised with its electric vector perpendicular to the plane of incidence

Answer 1

Answer: (D)

When reflected light rays and refracted rays are perpendicular, reflected light is polarised with electric field vector perpendicular to the plane of incidence.

Also, $\tan \, i = \mu$ (Brewster angle)