Two coils A and B have, initially, a mutual inductance of 250 mH, and the current in coil A is 2 A. Then, in a time interval of length 0.2 seconds, coil A is moved closer to coil B, so that, at the end of these 0.2 seconds, the mutual inductance increases from 250mH to 500mH. Assuming that the current in coil B is kept constant at 2 A during these 0.2 seconds, calculate, approximately, the average value of the voltage induced in coil B during this 0.2 second period.

Two coils A and B have, initially, a mutual inductance of 250 mH, and the current in coil A is 2 A. Then, in a time interval of length 0.2 seconds, coil A is moved closer to coil B, so that, at the end of these 0.2 seconds, the mutual inductance increases from 250mH to 500mH. Assuming that the current in coil B is kept constant at 2 A during these 0.2 seconds, calculate, approximately, the average value of the voltage induced in coil B during this 0.2 second period.