Fuses prevent electrical overloads in appliances

Steps:

• Identify the role of a fuse: it contains a thin wire that melts under excessive current.
• Understand overload: high current from faults can cause overheating and fires.
• Fuse action: melting wire breaks the circuit, stopping current flow.
• Result: protects the appliance and wiring from damage.

Why B is correct:

• A fuse protects by breaking the circuit when current exceeds the rated value, per Ohm's law where I = V/R, preventing excess heat (P = I²R).

Why the others are wrong:

• A: Earthing grounds excess charge to prevent shocks, not a fuse's function.
• C: Fuses do not alter power output; they only interrupt flow.
• D: Voltage regulation uses transformers, not fuses.

Final answer: B