In a Young's double slit experiment, the slits are separated by 0.2 mm. If the slits separation is increased…
In a Young's double slit experiment, the slits are separated by 0.2 mm. If the slits separation is increased to 0.4 mm , the percentage change of the fringe width is:
$0 \%$
$100 \%$
$50 \%$
$25 \%$
Solution
$\beta=\frac{\mathrm{D} \lambda}{\mathrm{~d}} \propto \frac{1}{\mathrm{~d}}$ If d is doubled then $\beta$ is half so $50 \%$ decrement.