Question

A piece of a diamagnetic material, free to move when placed in a uniform magnetic field:

• A. moves along the field
• B. moves opposite to the field
• C. moves perpendicular to the field
• D. does not move at all

Hint:

Diamagnetic materials move only in non-uniform magnetic fields where they experience a net repulsive force. In uniform fields, there is no movement.

Answer 1

The Correct Option is D

Diamagnetic materials are repelled by magnetic fields because they create an induced magnetic moment in a direction opposite to the applied magnetic field. However, in a uniform magnetic field, the magnetic force on a diamagnetic object is zero because the net force depends on the gradient of the magnetic field. In a non-uniform field, the object would move toward the region of weaker field. Since the field is uniform here, the diamagnetic piece experiences no net force, and hence does not move.