In YDSE, water is filled in the space between the slits and screen. Then

Options

A. Fringe pattern shifts upward but fringe width remains unchanged
B. fringe width decreases and fringe pattern shifts upward
C. fringe width remains unchanged and central fringe does not shift
D. fringe width decreases and fringe pattern does not shift

Answer

d

Explanation

Fringe width `= (lambda_("medium") D)/(d) = (lambda D)/(mu d)`
As `mu gt 1`, so fringe width decreases. Fringe pattern doesn't shift because same path length change is introduced in both the waves.