Question

A coil ABCD mounted on an axle is placed between the poles N and S of a permanent magnet as shown in figure. In which direction will be coil begin to rotate when current is passed through the coil in direction ABCD by connecting a battery at the ends A and D of the coil?

• A. clockwise
• B. anticlockwise
• C. both A & B
• D. none of the above

Answer 1

The correct option is B anticlockwise

When a steady current flows through the circuit, a magnetic field is set up by the rectangular coil ABCD due to the passage of current. The magnetic field in the coil is at right angles to the magnetic field of the permanent magnet. Thus, a magnetic couple acts, which rotates the coil. When current is passed through the coil in direction ABCD by connecting a battery at the ends A and D of the coil, the rectangular coil ABCD will rotate about its axis. The arm CD of the coil will move out of the plane of paper and arm AB will move into the plane of paper.
Thus, the coil will move in the anticlockwise direction.