In YDSE, the source placed symmetrically with respect to the slit is now moved parallel to the plane of the slits it is closer to the upper slit, as shown then

Options

A. the fringe width will increase and fringe pattern will shift down
B. the fringe width will remain same but fringe pattern will shift up
C. the fringe width will decrease and fringe pattern will shift down.
D. the fringe width will remain same but fringe pattern will shift down.

Answer

D

Explanation

Fringe width remains unchanged `beta=(lamdad)/(D)`
But central bright fringe (zero path difference shift downwards therefore whole fringe pattern shifts downwards).