Question

A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each

• A. Two revolutions
• B. One revolution
• C. Half revolution
• D. One-fourth revolution

Answer 1

The correct option is C

Half revolution

1. The direction of the induced current in a rectangular copper coil changes once per half revolution when rotated in a magnetic field.
2. As a result, the direction of the current in the coil remains unchanged.
3. The current induced by the magnetic field in the rectangular coil composed of copper wire is rotated in order to rotate in the magnetic field.
4. At each turn, the direction of the induced current changes, and because the induced current is a vector quantity, it changes every half revolution.
5. Because the direction of relative motion of the coil and the magnetic field changes every half cycle, the direction of the induced current changes once every half rotation.

Hence, option c is correct.