Voltage, Current and Resistance - Engineering

Q1:

Current flows in a circuit when

A a switch is opened

B a switch is closed

C the switch is either open or closed

D there is no voltage

ANS:B - a switch is closed

Current flow always in a closed circuit.

For eg:

If you have two Wire and a lamp.
Then both wire first terminal you connect to the lamp and second terminal you connect only one wire. Then the lamp can't blow.

The reason is the circuit is not complete.
And again we connected both wires then lamp give light.

So the flow of current is important to close the circuit.