Question

Two circular loops lie side by side in the same plane. One is connected to a source that supplies an increasing current, the other is a simple closed ring. Is the induced current in the ring is in the same direction as that in the loop connected to the source or opposite? What if the current in the first loop is decreasing?

Answer 1

As you know according to Faraday's induction law or Lenz's law, an induced current creates a magnetic field that opposes any change in the magnetic flux of the ring. So your answer is that the current in the ring flows in the same direction as the current in the loop connected to the source. When the current increases it creates a magnetic flux which goes through the other loop too. So a current should be induced in that loop which opposes this magnetic flux. Try to imagine the loops side by side, if the magnetic field created by loop A is coming out of the page when it enters loop B it is going into the page. So if the current in loop B is to oppose this magnetic field, it should create a magnetic field which would come out of the page so it should be in the same direction as the current in loop A.

But if the current in the loop connected to the source was decreasing the currents would be in opposite directions.