Question

Question 12
In the circuit shown in Fig, when the key is closed, the compass needle placed in the matchbox deflects. Name the force which causes this deflection.

Answer 1

The force which causes the deflection of the compass needle when the key is closed in a circuit and the electric current flows through the circuit is the magnetic effect of electric current.
The current flowing in the circuit produces a magnetic field around it which causes the compass needle to deflect.