question_answer

In a double slit experiment, when a thin film of thickness t having refractive index m is introduced in front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of t is (\[\lambda \]is the wavelength of the light used) :                    [JEE Main Held on 12-4-2019 Morning]

A) \[\frac{\lambda }{2(\mu -1)}\]                       

B) \[\frac{\lambda }{(2\mu -1)}\]

C) \[\frac{2\lambda }{(\mu -1)}\]                       

D) \[\frac{\lambda }{(\mu -1)}\]

Correct Answer: D

Solution :

\[\Delta X=(\mu -1)t=1\lambda \]for one maximum shift \[\]