KVPY 2019 SB SX Exam Previous Papers

Unpolarised red light is incident on the surface of a lake at incident angle ${\mathit{\theta }}_{\mathit{R}}$. An observer seeing the light reflected from the water surface through a polarizer notices that on rotating the polarizer, the intensity of light drops to zero at a certain orientation. The red light is replaced by unpolarised blue light. The observer sees the same effect with reflected blue light at incident angle ${\mathit{\theta }}_{\mathit{B}}$. Then,