Question

what happens to the deflection of needle when current in conductor is increased

Answer 1

The deflection also increase towards the direction of the magnetic field

Answer 2

(a) If we increase the current in the conductor, the deflection of the compass needle increases. This shows that, the magnitude of the magnetic field produced at a given point is directly proportional to the current passing through the wire. That is B∝ Ι

(b) On changing the direction of flow of current, the direction of deflection of compass needle is reversed.

(c) For a given current, if we move the compass needle away from the wire, its deflection decreases. This shows that the magnitude of the magnetic field produced by a given current in the wire is inversely proportional to the distance from the wire.