Question

If Young's double slit experiment, is performed in water

• A. the fringe width will decrease
• B. the fringe width will increase
• C. the fringe width will remain unchanged
• D. there will be no change

Answer 1

Answer: (A)

the fringe width will decrease

Answer 2

Fringe width
$\beta = \frac{D \lambda}{d}....(i)$
and $\lambda ? \frac{1}{\mu} ....(ii)$
From Eqs. (i) and (ii)
$\beta ? \lambda ? \frac{1}{\mu}$
$\therefore \beta ? \frac{1}{\mu}$
Hence, (a) is correct.