Question

Consider two coherent sources S1 and S2 producing monochromatic waves to produce interference pattern.

Answer 1

Given, 

For sources S₁ and S₂ 

y₁ = a cos ωt

y₂ = a cos (ωt + φ)

Resultant intensity I = 4 a² cos² (φ/2)

For wave - 1, A₁ = A = a

For - 2

A₂ = a, Δφ = φ