Q6.14 (e) Figure 6.20 shows a metal rod resting on the smooth rails and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer connects the rails through a switch . Length of the , , resistance of the closed loop containing the . Assume the field to be uniform. Suppose K is open and the rod is moved with a speed of in the direction shown. Give the polarity and magnitude of the induced emf.
(e) How much power is required (by an external agent) to keep the rod moving at the same speed when is closed? How much power is required when is open?