Unpolarized light falls from air onto a planar air-glass interface (refractive index of glass is 1.5) at an angle θ1. If the reflected light is observed to be completely plane polarized, then the angle θ1 (in degrees) to the nearest integer is:

Which Indian independence movement leader was primarily known for his philosophy and practice of non-violent civil disobedience?

Who gave the call for 'Do or Die' during the Quit India Movement in 1942?

Which of the following revolutionary pairs were imprisoned together in Cellular Jail and faced harsh conditions, contributing significantly to the Indian independence movement?