A cylindrical bar magnet is rotated about its axis (Figure). A wire is connect from the axis and is made to touch the cylindrical surface through a contact. Then

Options

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

Answer

B

Explanation

As there is no change in magnetic flux associated with the circuit, no current is induced in the circuit. The ammeter A shows no deflection. Choice (b) is correct.