A conducting rod of mass m, length l, free to rotate in a vertical plane, is hinged at point O. There exists a uniform magnetic field vector B in horizontal direction. The rod is released form the position shown. The potential difference between the two ends of the rod, when it reaches a position at an angle θ below the initial position, is proportional to
(a) √sinθ
(b) l2
(c) B
(d) l3/2
