Question

What is short circuiting? State one factor, condition that can lead to it Name a device in the household that acts as a safety measure for it State the principle of its working.

CBSE Class X Science SA 2 (3 Marks)

Answer 1

Situation in which live and neutral wire come in direct contact, abruptly increasing the current in the circuit is called short–circuiting. 1 Factor – Insulation of wire is damaged / fault in appliance.
Safety device – Electric fuse.
Electric fuse is an application of Joule’s heating. If there is a current larger than the specified value the temperature of fuse wire increases and it melts to break the electric circuit and stop the flow of unduly high electric current

Answer 2

Direct connection of  phase wire with neutral wire becomes short circuit.

faults in electric appliances, wet electric devices, loose wires, loose  connections, or overheated wires...  connection of very small load between phase or live wire and neutral wire.

Safety fuse or a circuit breaker device is used as a safety measure.

When excess current flows the circuit breaker breaks the connection , because of the force due to larger induced current due to excess current in the mains.

When excess current flows through a fuse wire, the wire melts due to low melting point.  so circuit breaks.