What term describes a resistor whose resistance can be adjusted to vary current flow?

What term describes a resistor whose resistance can be adjusted to vary current flow?

• A. Fixed resistor
• B. Variable resistor
• C. Capacitor
• D. Inductor

Answer: (B)

Understanding how resistance relates to current is key here. A resistor whose resistance can be adjusted to vary current flow is called a variable resistor. By turning its knob or slider, you change the resistance, and with a fixed voltage source, that changes the current according to I = V/R. Increase the resistance and the current drops; decrease the resistance and the current rises. This is exactly what a variable resistor is designed to do—let you tune how much current passes through a circuit. A fixed resistor has a constant resistance, so it doesn’t change current unless you replace the component. A capacitor stores energy in an electric field and presents an impedance that depends on frequency, not a simple adjustable resistance. An inductor stores energy in a magnetic field and opposes changes in current through inductive reactance, again not a simple, adjustable resistance.

Understanding how resistance relates to current is key here. A resistor whose resistance can be adjusted to vary current flow is called a variable resistor. By turning its knob or slider, you change the resistance, and with a fixed voltage source, that changes the current according to I = V/R. Increase the resistance and the current drops; decrease the resistance and the current rises. This is exactly what a variable resistor is designed to do—let you tune how much current passes through a circuit.

A fixed resistor has a constant resistance, so it doesn’t change current unless you replace the component. A capacitor stores energy in an electric field and presents an impedance that depends on frequency, not a simple adjustable resistance. An inductor stores energy in a magnetic field and opposes changes in current through inductive reactance, again not a simple, adjustable resistance.