Question

At the time of the short circuit, the current in the circuit.

• A. reduces substantially
• B. does not change
• C. increases heavily
• D. vary continuously

Answer 1

The correct option is C

increases heavily

Explanation for the correct answer,

In the case of option C,

1. When the torn plastic insulation of neutral wires touches each other, then an electric short circuit occurs due to this direct touching of the two wires.
2. The current flowing through the wires increases heavily because the resistance of the circuit formed is very small.
3. A short circuit occurs when the current in the circuit rises rapidly and the electrical connection draws an excessive amount of current from the supply.
4. By Ohm's Law, $V=IR$, Since $V$ remains the same and $R$ is reduced significantly, the current suddenly increases.
5. During this time, the current has a very large magnitude. It occurs when the neutral and live wires come into contact.
6. The live wire carries current to the appliance at high voltage.
7. The neutral wire completes the circuit and carries current away from the appliance.
8. Resistance is a measure of how hard it is for the current to flow through the circuit.
9. When live wire touches neutral wire due to defect, worn out, or damaged wiring, the resistance becomes zero, and a large current flows through it, there will be a short circuit.
10. If the insulation on the wires in the circuit is damaged or the appliance is defective, the live and neutral wires come into direct contact, causing current to rise in the circuit and a short circuit to arise.
11. In that case the protective device such as a circuit breaker or line fuse is supposed to operate or trip.
12. Short circuit means there is no voltage difference between the two points in the circuit.
13. It is characterized by infinitely small resistance.
14. Hence by ohms law large current flows through it.
15. So, at the time of the short circuit, the current in the circuit increases heavily.

Hence option C is the correct option.