A cylindrical bar magnet is rotated about its axis as in figure. A wire is connected from the axis and is made to touch the cylindrical surface through a contact. Then

Options

A. a direct current flows in the ammeter A.
B. no current flows through the ammeter A.
C. an alternating sinusoidal current flows through the ammeter A with a time period `T=(2pi)/omega`
D. a time varying non-sinusoidal current flows through the ammeter A.

Answer

B

Explanation

When magnet is rotated with respect to its own axis, there is no change in the flux linked with it. As there is no change in the magnetic flux linked with the circuit hence no current is induced in the circuit.