Question

A copper rod is suspended a non-homogeneous magnetic field region. The rod when in equilibrium will align itself:

• A. in the region where magnetic field is strongest
• B. in the region where magnetic field is weakest and parallel to direction of magnetic field there
• C. in the direction in which it was originally suspended
• D. in the region where magnetic field is weakest and perpendicular to the direction of magnetic field there

Answer 1

Answer: (D)

in the region where magnetic field is weakest and perpendicular to the direction of magnetic field there

Copper is a diamagnetic substance and in diamagnetic materials a small magnetisation occurs opposite to the external applied magnetic field, thus are weakly repelled by the magnet.

So, when a rod of diamagnetic substance is suspended in the magnetic field, the rod becomes perpendicular to the field in the region of weakest magnetic field.