Which component is used to limit current flow in a circuit?

• A. Battery
• B. Resistor
• C. Switch
• D. Light bulb

Answer: (B)

Current in a circuit is controlled by resistance. According to Ohm’s law, current equals voltage divided by total resistance, so adding a known resistance sets how much current can flow for a given supply voltage. A resistor is designed to provide that fixed resistance, making it the standard way to limit current and protect other components from drawing too much. The battery supplies the push that creates current but doesn’t limit it by itself. A switch simply connects or breaks the circuit, controlling whether current can flow. A light bulb is a load that consumes energy and has its own changing resistance as it heats, so it’s not a dedicated current-limiting device. Thus, the resistor is the component used to limit current flow.