A short-circuit happens when:
ALive and neutral wires touch directly
BEarth wire breaks
CVoltage is too low
DInsulation is too thick
Answer & Solution
Correct answer: A. Live and neutral wires touch directly
1. Short-circuit: live and neutral wires come into direct contact (low-resistance path).
2. Current shoots up dramatically (I = V/R, R very small).
3. Generates intense Joule heat — fire hazard.
4. A correctly rated fuse should melt instantly and break the circuit.
_Source: NCERT Class 10 Science Ch 12 §12.8.1 Short-Circuit_
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