Question

An unpolarized light with an intensity of 20W/m^2 is passed through a pair of polarizers. The first polarizer is set at an angle of 60° and the second is set at an angle of 20°. Using Malus' law, what is the intensity of light as it passes through the second polarizer?

Answer 1

4.416 W/m²

Step-by-step explanation:

Malus' law is given mathematically as

I = I₀ cos² θ

For the first polarizer, θ = 60°

I₁ = I₀ cos² 60°

I₁ = I₀ (0.5)² = 0.25I₀

For the second polarizer, θ = 20°

I₂ = I₁ cos² 20°

I₂ = I₁ (0.9397)² = 0.883 I₁

I₂ = 0.883 × 0.25I₀ = 0.2208 I₀

Note that

I₀ = 20 W/m²

I₂ = 0.2208 × 20 = 4.416 W/m²

Hope this Helps!!!