Answer

.......................................................................................................................................................... l A solenoid has a crosssectional area of 7.7 x 10'4 m2, consists of 390 turns per meter, and carries a current of 0.51 A. A 18-turn coil is wrapped tightly around the circumference of the solenoid. The ends of the coil are connected to a 2.1-5: resistor. Suddenly, a switch is opened, and the current in the solenoid dies to zero in a time of 0.064 5. Find the average current induced in the coil