Question

At the first minimum adjacent to the central maximum of a single-slit diffraction pattern. the phase difference between the Huygen's wavelet from the edge of the slit and the wavelet from the midpoint of the slit is

(a) π radian

(b) π/8 radian

(c) π/4 radian

(d) π/2 radian

Answer 1

Correct option  (a) π radian

Explanation:

The situation is shown in the figure.

In figure A and B represent the edges of the slit AB of width a and C represents the midpoint of the slit. For the first minimum at P,

asinθ = λ ..............(i)

where λ  is the wavelength of light.

The path difference between the wavelets from A to C is