Problem 3PE

Referring to Figure 23.57(a), what is the direction of the current induced in coil 2: (a) If the current in coil 1 increases? (b) If the current in coil 1 decreases? (c) If the current in coil 1 is constant? Explicitly show how you follow the steps in the Problem-Solving Strategy for Lenz's Law.

Solution 3PE

a.) Since the resultant magnetic flux in the coil 2 due to coil 1 is into the plane of the coil, as current in the coil 1 increases, the induced current in the coil 2 will be to oppose the flux due to coil 1. Hence the direction of the induced current in the coil 2 will be counter clock wise.

b.) Since the resultant magnetic flux in the coil 2 due to coil 1 is into the plane of the coil, as current in the coil 1 decreases, the induced current in the coil 2 will be to aid the flux due to coil 1. Hence the direction of the induced current in the coil 2 will be clock wise.

c.) Since the flux due to the coil 1 in coil 2 does not change (the current in coil 1 is constant), the induced current in the coil is zero.