This question is gaining popularity among the candidates. Although quite a number were unable to state up to three methods of polarizing an unpolarised light, many were able to list correctly three types of wave that can be plane polarized, notably member of the electromagnetic spectrum. The expected answers are:
Three waves other than light that can be plane polarized [ ½ each x 3 = 1 ½ ]
e.g - X- ray
Radio waves
Gamma rays
Infrared radiation
Ultraviolet radiation.
1.) Three methods of polarizing an unpolarised light [ ½ each x 3 = 1 ½ ]
e.g by passing an unpolarised light through a Polaroid
polarizing by pile of plates
By reflection
By double refraction
By selective absorption by crystals
