Question

A current carrying circular coil, suspended freely in a uniform external magnetic field orients to a position of stable equilibrium. In this state:

• A. the plane of the coil is normal to the external magnetic field
• B. the plane of the coil is parallel to the external magnetic field
• C. flux through the coil is minimum
• D. torque on the coil is maximum

Answer 1

Answer: (A)

When a current carrying coil is suspended freely in a uniform magnetic field, the magnetic field exerts a force on coil to bring the axis of coil parallel to the direction of field. Since, axis of coil is perpendicular to its plane. Then when axis of coil is parallel to the direction of magnetic field, then plane of coil will be perpendicular to the magnetic field.