NEET2026PhysicsChapterActual
A beam of unpolarised light is incident on a transparent liquid surface at Brewster's angle. A Polaroid analyzer is placed first in the path of the reflected ray and then in the path of the refracted ray. As the analyzer is rotated completely through 360^ about the direction of wave propagation in each path, the intensity of the light transmitted through it:
Options
- Abecomes zero twice for both the reflected and refracted rays.
- Bbecomes zero twice for the reflected ray, but never becomes zero for the refracted ray.
- Cnever becomes zero for the reflected ray, but becomes zero twice for the refracted ray.
- Dremains constant for the reflected ray, but varies for the refracted ray.
Correct answer
B. becomes zero twice for the reflected ray, but never becomes zero for the refracted ray.
Step-by-step solution
When unpolarised light is incident at Brewster's angle, the reflected light is completely plane-polarised, with its electric field vector perpendicular to the plane of incidence. The refracted light is partially polarised, containing a mixture of both parallel and perpendicular components of the electric field. When a Polaroid analyzer is placed in the path of the completely plane-polarised reflected ray and rotated through 360^ , the transmitted intensity varies according to Malus's law, I = I₀ ^2 . The intensity