question_answer

Two coherent plane light waves of equal amplitude makes a small angle a (« 1) with each other. They fall almost normally on a screen. If \[\lambda \] the wavelength of light waves, the fringe width \[\Delta x\]of interference patterns of the two sets of waves on the screen is     JEE Main  Online Paper (Held On 19  May  2012)

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

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

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

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