The electric fields of two light sources with nearby frequencies o and o2, and wave vectors k and k2, are expressed as e- epiee-ot)and e, = eoi e-) respectively

The electric fields of two light sources with nearby frequencies o and o2, and wave vectors k and k2, are expressed as E- EpieE-ot)and E, = Eoi e-) respectively. The interference pattern on the screen is photographed at t = lo; denote (k,-k,)z- (o-0,), by . For this patten (A) abright fringe will be obtained for cos0=-1 (B) a bright fringe intensity is given by (E0) +(E0) (C) adark fringe will be obtained for cos=1 D) adark fringe intensity is given by (Eo-Ez)