A circular coil of radius 8.0 cm and 20 turns is rotated about its vertical diameter with an angular speed of 50 rads−1 in a uniform horizontal magnetic field of magnitude 3.0×10−2T. Obtain the maximum and average emf induced in the coil. If the coil forms a closed loop of resistance 10Ω , calculate the maximum value of current in the coil. Calculate the average power loss due to Joule heating. Where does this power come from?
Maximum induced emf e=NωAB;N=no. of turns,ω=angular speed,A=Area of coil,B=Magnetic field⇒e=0.603VOver a full cycle, the average emf induced in the coil is zero.
Maximum current, I=e/R=0.0603
Average power loss due to joule heating is P=eI2=0.018 W