Consider Fraunhoffer diffraction pattern obtained with a single slit illuminated at normal incidence. At the angular position of the first diffraction minimum the phase difference (in radians) between the wavelets from the opposite edges of the slit is

Options

A. `pi/4`
B. `pi/2`
C. `2pi`
D. `pi`

Answer

C

Explanation

Path difference between the opposite edges is `lamda`.
For a phase difference of `2pi` we get a path diff. of `lamda`