question_answer

In Young's double slit experiment, one of the slit is wider than other, so that amplitude of the light from one slit is double of that other slit. If\[{{I}_{m}}\]be the maximum intensity, the resultant intensity I when they interfere at phase difference\[\phi \] is given by

A) \[\frac{{{I}_{m}}}{9}(4+5\cos \phi )\]   

B) \[\frac{{{I}_{m}}}{3}(1+2{{\cos }^{2}}\frac{\phi }{2})\]

C) \[\frac{{{I}_{m}}}{5}(1+4{{\cos }^{2}}\frac{\phi }{2})\]

D)        \[\frac{{{I}_{m}}}{9}(1+8{{\cos }^{2}}\frac{\phi }{2})\]