Which component restricts the flow of electric current?

Which component restricts the flow of electric current?

• A. Relay (relay switch)
• B. Two-way switch
• C. Resistor (nonvariable)
• D. Dual on/off switch

Answer: (C)

The key idea is that a resistor is the component designed to limit how much current can flow in a circuit. Resistors have a fixed resistance, and according to Ohm’s law, current is equal to voltage divided by resistance (I = V/R). When you increase the resistance, the current drops; when you decrease it, more current flows—within the limits of the supply. This ability to set a specific current makes resistors essential for protecting components, biasing devices, and dropping voltage to safe levels. The other devices are primarily switches. A relay is an electrically controlled switch that can turn a circuit on or off; it may have some resistance in its coil and contacts, but that’s not its purpose. A two-way switch simply routes current along one of two paths, and a dual on/off switch provides toggling between connections. They don’t impose a controlled, fixed resistance to limit current, so they aren’t the component that restricts current.

The key idea is that a resistor is the component designed to limit how much current can flow in a circuit. Resistors have a fixed resistance, and according to Ohm’s law, current is equal to voltage divided by resistance (I = V/R). When you increase the resistance, the current drops; when you decrease it, more current flows—within the limits of the supply. This ability to set a specific current makes resistors essential for protecting components, biasing devices, and dropping voltage to safe levels.

The other devices are primarily switches. A relay is an electrically controlled switch that can turn a circuit on or off; it may have some resistance in its coil and contacts, but that’s not its purpose. A two-way switch simply routes current along one of two paths, and a dual on/off switch provides toggling between connections. They don’t impose a controlled, fixed resistance to limit current, so they aren’t the component that restricts current.