A fan blade of length 0.5 m rotates perpendicular to a magnetic field of 5x10 -5 T. If the e.m.f induced between the centre and the end of the blade is 10 -2 V . Find the rate of rotation Share with your friends Share 4 Vaibhav T. answered this Dear Student, Let n be the required number of rotation in one second. The magnitude of induced emf is given bye=Ndϕdte=NddtBAe=BdAdt ......because N=1where, A is the area swept by the blade in one revolution and dt is the time taken to complete one revolution.e=10-2 V, B=5×10-5 T, A=π×0.52, dt=1ns10-2=5×10-5×π×0.521nn=10-25×10-5×π×0.52n=254.77 rev/s 10 View Full Answer