Question

If I keep the north pole of a bar magnet facing a conducting loop and move it towards the loop, I find a current flowing through it, let's say in the clockwise direction. If I want a current to flow in the counter-clockwise direction using the same bar magnet, I should

• A. Move the north pole towards the loop in the same way but faster.
• B. Keep the south pole facing the loop and move it towards the loop.
• C. Keep the north pole facing the loop and move it away.
• D. Both (b) and (c).

Answer 1

The correct option is D

Both (b) and (c).

If the north pole is brought closer to the loop, that face of the loop will become north pole (Lenz law). Now as we want to reverse the current hence, we need to develop a south pole on the loop that can be done either by moving the north pole away from the loop or moving south pole towards the loop.