Question

The transverse nature of light waves is verified by
A. reflection of light
B. polarisation of light
C. refraction of light
D. interference of light

Answer 1

Hint: Light is a transverse wave. That means the vibrating electric field is perpendicular to the direction of propagation of light. However, ordinary light has the plane of electric field in all the directions called polarised light. Polarised light has a specific plane of electric field. If the light can be polarised then it will be proved that it is a transverse wave.

Complete step by step answer:
Let us first understand what is an ordinary light. We all know that light is a wave. A wave has direction of propagation and a direction of the vibrations. If the vibrations and the propagation of waves are in the same direction that the waves is called a longitudinal wave. If the vibrations are in a plane perpendicular to the propagation then the wave is called a transverse wave.
In light, the vibrations are of electric and magnetic fields. Here, the pLane of vibrations in an electric (oscillating electric field) is perpendicular to the direction of propagation of the light wave. Therefore, light is a transverse wave.
The plane of vibrations of electric fields may be in all the directions. When this plane is not in a specific direction, the light is called unpolarised light.
When the plane of vibrations of an electric field is in a specific direction, the light is called polarised light.
An unpolarised light can be polarised. And this proves the transverse nature of light. When an unpolarised light is passed through a crystal called polariser, the light is polarised. The process of converting an unpolarised light into a polarised light is called polarisation of light.
A polariser has the plane of transmission in a specific direction. Therefore, when the unpolarised light passes through the polariser, the transmitted light has the plane of vibrating electric field in that specific direction. Hence, the light is polarised.
Hence, the correct option is B.

Note: Let us understand what are the phenomena mentioned in the options in brief.
(i) Reflection of light : It is the phenomenon of bouncing back of light when it falls on the surface of a body.
(ii) Refraction of light : It is the phenomenon of bending of light when the light passes from one medium to another.
(iii) Interference of light : It is the phenomenon of two waves of light superimposing to form a resulting wave of different amplitude.