Which statements are correct for the superposition of two coherent sinusoidal waves having intensities I₁ and I₂ and phase difference φ?
Select all that apply

Question

Which statements are correct for the superposition of two coherent sinusoidal waves having intensities I₁ and I₂ and phase difference φ?

G1 Physics · Accepted Answer

The general resultant intensity is I = I₁+I₂+2√(I₁I₂) cosφ. For φ = 0, Iₘₐₓ = (√I₁+√I₂)². For φ = π, Iₘᵢₙ = (√I₁−√I₂)². For complete cancellation, Iₘᵢₙ = 0, which requires √I₁ = √I₂, so the amplitudes must be equal. Therefore all four statements are correct.