Question

A magnetic compass shows a deflection when placed near a current-carrying wire. How will the deflection of the compass get affected if the current in the wire is increased? Support your answer with a reason.

Answer 1

Magnetic field produced by the current-carrying wire:

1. A magnetic compass is made by using magnetized iron and that iron points towards the pole of the earth.
2. When another magnet is brought near, the compass will basically point on towards the other magnet as its magnetic strength is known to be stronger than the earth’s magnetic strength.
3. When a current-carrying wire is brought close to a magnetic compass then there will be a deflection in the magnetic compass due to the magnetic field formation.
4. The magnetic field around a wire carrying an electric current will form concentric circles around the wire.
5. Based on the orientation of the magnet, one of the ends will attract and the other end will repel.
6. $B=\frac{{\mu }_{0}I}{2\mathrm{\pi R}}$ Here B is directly proportional to the current I.

Affected on the magnetic field if the current in the wire is increased:

1. The deflection will tend to increase when the current in the wire is increased.
2. The strength of the magnetic field is directly proportional to the magnitude of the electric current through the wire.
3. When a current-carrying wire is brought close to a magnetic compass then there will be a deflection in the magnetic compass due to the magnetic field formation.
4. The deflection increase with the increased current in the wire because the magnetic force is directly proportional to the magnetic field strength.
5. Thus, we can say that the stronger the current, the stronger the magnetic force acting on the needle of the magnet.

Hence, if the current is increased in the conductor then the deflection of the compass needle increases, this is because the strength of the magnetic field varies directly as the magnitude of the electric current or the current passing through the wire.