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 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-sinosoidal flows through the ammeter `A`.

Answer

B

Explanation

When cyllindrical bar magnet is rotated about its axis, no charge in flux linked with the circuit tajes place consequently no emf induced and hence, no current flows through the ammeter `A`