question_answer

Two coherent plane light waves of equal amplitude makes a small angle \[\alpha (<<1)\] with each other. They fall almost normally on a screen. If \[\lambda \]is the wavelength of light waves, the fringe width \[\Delta x\] of interference patterns of the two sets of waves on the screen is

A) \[\frac{2\lambda }{\alpha }\]                  

B)        \[\frac{\lambda }{\alpha }\]

C) \[\frac{\lambda }{(2\alpha )}\]    

D)        \[\frac{\lambda }{\sqrt{\alpha }}\]