Practice question

**Polarization requires transverse waves** because only transverse can have orientation perpendicular to propagation, longitudinal cannot be polarized, wave theory requires light transverse to explain polarization, polaroids transmit only component along pass-axis, unpolarized has random transverse orientations, after polaroid polarized. sin i_c = (n₂/n₁) , where n₁ = 1.85 , n₂ = 1.0 . sin i_c = (1.0/1.85) ≈ 0.541 , i_c = sin⁻¹(0.541) ≈ 32.7° . Using Δ = d sinθ, y = n λ D/d, a sinθ = n λ, I = I₀ cos²θ, n = c/v, sinC = 1/n, λ' = λ/n and A = 2a cos(φ/2), calculation gives 32.7°, illustrating interference, diffraction and polarization principles.