Question

A solenoid coil.has 10^4 turns of fine insulated conducting wire. The main cross sectional area of the coil is 4000m^2. The magnetic field through the coil changes at a uniform rate of 0.8T to -0.4T in a time of 3s. If the circuit resistance of the coil is 12ohms. Calculate (1).the charge made to pass a cross section of the circuit. (2).the average current (3).the instantaneous current when the magnetic field is zero