Which component is commonly used in a circuit to vary the resistance?

Correct option is C

Correct Answer: (C) Rheostat

Explanation:

• A rheostat is a variable resistor commonly used in electrical circuits to vary the resistance and control the current flow.
• It allows you to adjust the resistance without changing the physical components of the circuit. Rheostats are often used in applications like dimming lights, controlling motor speeds, or adjusting audio volume.

Information Booster:

• Diode: A semiconductor device that allows current to flow in one direction but not the other, typically used for rectification.
• Voltmeter: A device used to measure voltage (potential difference) in a circuit, not to vary resistance.
• Transformer: An electrical device used to change the voltage level in an AC circuit, not related to varying resistance.