Three coherent slits A, B and C are arranged as shown. Given BP₀-AP₀=λ/3 and d=√(2λD/3), find the ratio of intensity at P₀ to the intensity due to one slit.

Question

G1 Physics · Accepted Answer

Using the given geometry and the relation d²=2λD/3, the path differences of the three equal-amplitude waves at P₀ give phasors whose resultant amplitude is √3 times one-wave amplitude. Hence I(P₀)=3the one-wave intensity. Option D.