Malus’s Law:

I = I₀ cos²θ

where I = transmitted intensity

I₀ = initial intensity

θ = angle between polarizer and analyzer

Brewster’s Law:

tan θ_p = n

where θ_p = polarizing angle

n = refractive index of medium

Intensity of Polarized Light:

I = I₀/2 (for unpolarized light through polarizer)

I = I₀ cos²θ (for polarized light through analyzer)

Amplitude Relation:

A = A₀ cosθ

where A = transmitted amplitude

A₀ = initial amplitude

θ = angle between polarization directions