If a heating element in a cigarette lighter develops a fault that reduces resistance, what is the immediate electrical consequence when plugged in?

• A. a higher current draw that can blow the fuse.
• B. a lower current draw.
• C. the current remains unchanged.
• D. the device will reverse polarity.

Answer: (C)

The main idea is Ohm's law: with a fixed supply, current through a resistor changes inversely with its resistance. The heating element in a cigarette lighter acts as a resistor connected to the car’s ~12 volts. If a fault reduces its resistance, more current will flow because I = V/R. That immediate consequence is a higher current draw than normal. If the circuit has protection, the fuse or circuit breaker may trip or blow due to this surge, cutting power to prevent damage. The current wouldn’t stay the same, and polarity reversal isn’t something caused by a resistance drop in this setup.