Will the compass needle show deflection when the switch in the circuit shown in Fig.14.24 is closed?

AcademicPhysicsNCERTClass 7


A circuit is shown in Fig.14.24.

To do:

To check whether the compass needle will show deflection when the switch in the circuit shown in Fig.14.24 is closed.


Let us observe the given circuit shown in fig. 14.24:

Observation of the circuit:

The following components are found while observing the circuit shown in the fig. 14.24.

1. Switch in open or 'OFF' position 

2. Connecting wires

3. An electric bulb

4. A coil

5. A compass

On observing the given circuit it can be seen clearly that the switch is in the 'OFF' position. So the circuit is not complete. 

One more thing to be noted is that there is no cell or battery connected to the circuit. So, even if the switch is closed, there will be no current to flow through the circuit.

Now we should get to know when a compass needle can deflect in a circuit.

How a compass needle can deflect:

A magnetic field is required for the deflection in the compass needle. If the current is not flowing through the circuit then no magnetic field will be created. If there is no magnetic field created then there will be no deflection in the needle of the compass.


Based on the observation of the circuit we can conclude that in the given figure, the circuit does not carry current. So, the needle of the compass will not show any deflection even after closing the switch as there is no power source connected to the circuit.

Updated on 10-Oct-2022 13:26:24