Question

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:

(1) \(0\ \%\)

(2) \(100\ \%\)

(3) \(50\ \%\)

(4) \(25\ \%\)

Answer 1

Correct option is : (3) \(50 \ \%\) 

\(\beta = \frac{D \lambda}{d} \propto \frac{1}{d}\)

If d is doubled then \(\beta\) is half so \(50 \ \%\) decrement.