At the first minimum adjacent to the central maximum of a single-slit diffraction pattern the phase difference between the Huygens wavelet from the edge of the slit and the wavelet from the mid-point of the slit is

Options

A. `(pi)/(8) radian`
B. `(pi)/(4) radian`
C. `(pi)/(2) radian`
D. `pi radian`

Answer

D

Explanation

Path difference between `AP` and `MP` for the first minima
`MP - AP = (lambda)/(2)` `(because n = 1)`

Phase difference `phi = (2pi)/(lambda) xx` path diff.
`= (2pi)/(lambda) xx (lambda)/(2) = pi` radian