Two point monochromatic and coherent sources of light of wavelength `lambda` are each placed as shown in the figure below. The initial phase difference between the sources is zero. Select the incorrect statement.

Options

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

Answer

D

Explanation

Path difference , `Deltax` at O is d.
So, if `d=(7lambda)/2`, O will be a minima.
If `d=lambda`, O will be maxima .
If `d=(5lambda)/2`, O will be minima and hence intensity is minimum
If d=4.8 `lambda` , then total 10 minimas can be observed on screen, 5 above and 5 below O, which correspond to
`Deltax=pm lambda/2, pm(3lambda)/2 , pm (5lambda)/2 , pm (7lambda)/2, pm(9lambda)/2`