Question

In Young’s double-slit experiment with slits of equal width, a point P on the screen is at a distance equal to one-fourth of the fringe width from the central maximum. If the intensity at the central maximum is I , find the intensity at P.

Answer 1

Data : y = \(\cfrac{W}4\)

path difference,

Since, the slits have equal width, the intensities of the two interfering waves are equal, say I₀. Then the intensity at a point on the screen is

I = 4I₀ cos² \(\cfrac{ϕ}2\)

At the central maximum, φ = 0.

The intensity at P is half that at the central maximum.