Unpolarised light is passed through a polarizer P1. When this polarised beam passes through another polarizer P2, and if the pass axis of P2 makes angle θ with the pass axis of P1, then write the expression for the polarised beam passing through P2. Draw a plot showing the variation of intensity when θ varies from 0 to 2π.

Here, E is unpolarized light passes through a polarizer P1 and again this polarized light passes through a polarizer P2, the pass axis of P2 makes angle θ with the pass axis of P1.

Expression for the polarised beam passing through the P2 is I = I₀cos²θ,

Here I = Intensity of unpolarized light, I₀ = Intensity of polarized light, and θ is the angle between Polarizer P1 and P2. This is known as Malus' law.