Question

Define the term “Linearly polarised light”.

Answer 1

Light is an electromagnetic wave. Light is an oscillating electric and magnetic field. The oscillations occur in more than one plane. The process of transforming unpolarised light into polarised light is called polarisation.

Complete step by step answer:
The process of transforming unpolarised light into polarised light is known as Polarisation.
The light wave in which the vibrations of the electric field are confined in one plane and parallel to one unique direction is called linearly polarised light. Polarised waves are the light waves in which the vibrations occur in only a single plane. Unpolarised waves are the light waves in which the vibrations occur in more than one plane.The electric field is confined to only a single plane along the direction of propagation of light. According to the law of Malus, the intensity of a beam of plane polarised light after passing through a polarizer (rotatable) changes to the square of the cosine angle through which the polarizer is rotated from the point of maximum intensity.$I = {I_o}{\cos ^2}\theta$, where I is the intensity of the linearly polarised light and ${I_o}$ is the intensity of the plane polarised light.The intensity of transmitted light becomes maximum when the polariser and analyser are parallel.That is when θ = 0.

Note: Difference between Linearly polarised light and plane polarised light is that the photons oscillate along the direction of propagation of light wave in linearly polarised light whereas in plane polarised light the photons oscillate perpendicularly to the direction of propagation of light wave. Do not confuse between these two.