Question

Four independent waves are expressed as:

1. y₁ = A₁ sin ωt
2. y₂ = A₂ sin 2ωt
3. y₃ = A₃ cos ωt
4. y₄ = A₄ sin(ωt + π/3)

The interference between two of these waves is possible in ______.

Options

• (i) and (iii) only

• (iii) and (iv) only

• (i), (iii) and (iv) only

• All of them

Answer 1

The interference between two of these waves is possible in (i), (iii) and (iv) only.

Explanation:

Interference requires waves to be coherent, meaning they must have the same frequency. Waves y₁, y₃, and y₄ all have an angular frequency of ω, whereas y₂ has a different frequency (2ω), making it incoherent with the others.