Question

An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by 30° in clockwise direction, the intensity of emerging light will be ______ Lumens.

Options

• 70

• 71

• 75

• 80

Answer 1

An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by 30° in clockwise direction, the intensity of emerging light will be 75 Lumens.

Explanation:

Given, 

I₀ = 100 Lumens

θ = 30°

I = I₀ cos²θ

So,   I = 100 cos²(30°)

= `100xx(sqrt3/2)^2 `

= 25 × 3

75 Lumens.