Short Circuit in Damaged Kettle

Steps:

• Fuse blows when current exceeds safe limit due to low-resistance path.
• Damage in kettle exposes wires, allowing unintended contact.
• Live wire contact with earth creates direct short circuit.
• High current flows, heating and melting fuse wire.

Why A is correct:

• Direct contact between bare live and earth wires forms a short circuit, drawing excessive current that exceeds fuse rating and causes it to blow (per Ohm's law: I = V/R, where low R yields high I).

Why the others are wrong:

• B: Casing touching live shorts via earth connection but specifies casing, not wires directly; fuse may blow, but A precisely describes internal wire fault.
• C: Neutral-earth contact creates minimal potential difference, so low current flows without blowing fuse.
• D: Earth-live contact in cable affects supply line, not kettle damage specifically.

Final answer: A