Q. In the figure shown, a uniform magnetic field 0.5 T is perpendicular to the plane of circuit. The sliding rod of length l = 0.25m moves uniformly with constant speed v = 4ms-1. If the resistance of the slides is 2Ω, then the current flowing through the sliding rod is
Sol: The rod can be replaced by a battery of emf e=Bvl and internal resistance r= 2 Ω .
Since , 12 Ω & 4Ω are in parallel . R ‘ = (12×4)/(12+4) = 3 Ω
Now 3 Ω is in series with 2 Ω , Req = 3 + 2 = 5 Ω
Hence current i = e/ Req = Bvl/5 = 0.5 × 4×0.25/5 = 0.1 A