Question

What happens to the deflection of a compass needle placed at a point near the current-carrying straight conductor if

1. The current is increased
2. The direction of the current is reversed
3. The compass is moved away from the conductor?

Answer 1

Part i:

1. If the current is increased, the deflection also increases.
2. It means on increasing the current through the conductor, the magnetic field also increases.

Part ii:

1. If the direction of the current is reversed, the deflection of the compass needle is also reversed.
2. It means that on reversing the current, the direction of the magnetic field is reversed.

Part iii:

1. If the compass is moved away from the conductor, the deflection of the needle decreases.
2. It means that the strength of the magnetic field decreases as the distance from the current-carrying conductor increases.