Question

A diamagnetic substance is brought near the north or south pole of a bar magnet. It will be :

Assertion (A) : When a bar of copper is placed in an external magnetic field, the field lines get concentrated inside the bar. Reason (R) : Copper is a paramagnetic substance.

Assertion (A): Diamagnetic substances exhibit magnetism. Reason (R): Diamagnetic materials do not have permanent magnetic dipole moment.

Write the principle and explain the working of a moving coil galvanometer. A galvanometer as such cannot be used to measure the current in a circuit. Why ?