Practice MCQ Questions and answers on Physics-GK

Magnetism is caused by the motion of electric charges.

Hammering a rod will either allow it to become slightly magnetic if laid along a magnetic field (i.e.North - South) or demagnetise it if laid across the field lines (i.e. East-West). A current passing through a coil will produce a magnetic field.

Magnetic keepers are pieces of soft iron that are placed across the poles of a bar magnet or a horseshoe magnet. They help prevent the loss of magnetism.

Curie point, also called Curie Temperature, temperature at which certain magnetic materials undergo a sharp change in their magnetic properties.

Tesla is a unit of magnetic field.

The domain theory of magnetism applies to Cobalt.

The paramagnetic theory of magnetism applies to Platinum.

A compass, which is used to assist in navigation, is an instrument that shows magnetic north. You must apply a correction to determine the direction of true north. The ability to steer a boat by a compass is useful if land is out of sight, visibility is reduced, or the boat operator is disoriented.
Mount a boat compass away from iron, magnets, and electrical wiring and equipment.

Hysteresis is found only in ferromagnetic materials.

Magnetic field lines about a current-carrying wire circle the wire in closed loops.