Two points nonochromatic and coherent sources of light of wavelength `lambda` each are placed as shown in figure. The initial phase difference between the sources is zero O. `(d gt gt d)`. Mark the correct statement(s).

Options

A. If `d = (7lambda)/(2)`, the point 'O' will be minima.
B. If `d = lambda` , only one maxima can be observed on screen
C. If `d = 4.8lambda` , then a total 10 minimas would be there on screen.
D. If `d = (5lambda)/(2)` , then Intensity at 'O' would be minimum.

Answer

A, B, C, D

Explanation

Path difference at 'O' is `Delta x = d`, which is maxima
(A) If `d = (7lambda)/(2)`, the point 'O' will be minima.
(B) If `d = lambda` , The point 'O' will be maxima.
(C ) If `d = 4.8 lambda` , then a total 10 minimas can be obsetved on screen 5 above 'O' and 5 below 'O', which corresponding to
`Delta x = +- (lambda)/(2), +- (3lambda)/(2), +- (5lambda)/(2), +- (7lambda)/(2) , +- (9lambda)/(2)` .
(D) If `d = (5 lambda)/(2)` , then 'O' will be minimum and hence intensity is minimum.