question_answer

In a Young's double slit experiment with light of wavelength\[\lambda \]the separation of slits is d and distance of screen is D such that \[D>>d>>\lambda .\]If the Fringe width is \[\beta ,\] the distance from point of maximum intensity to the point where intensity falls to half of maximum intensity on either side is :[JEE MAIN 11-04-2015]

A) \[\frac{\beta }{2}\]

B) \[\frac{\beta }{4}\]

C) \[\frac{\beta }{3}\]

D) \[\frac{\beta }{6}\]

Correct Answer: B

Solution :

[b]

Now