A rheostat is a variable resistor used to control the flow of current by adjusting resistance.

A rheostat is a variable resistor used to control the flow of current by adjusting resistance.

• A. Voltage
• B. Capacitance
• C. Current
• D. Resistance

Answer: (D)

A rheostat works by changing the opposition to current flow. It’s a variable resistor, so turning its control adjusts the resistance the circuit sees. With a fixed supply, current follows I = V/R, meaning increasing resistance lowers current and decreasing resistance raises current. Capacitance deals with storing charge and isn’t what a rheostat uses to regulate current. Voltage is the driving force, but the rheostat’s job is to alter resistance to control how much current actually flows. So understanding that the device’s function is to adjust resistance makes the choice best.

A rheostat works by changing the opposition to current flow. It’s a variable resistor, so turning its control adjusts the resistance the circuit sees. With a fixed supply, current follows I = V/R, meaning increasing resistance lowers current and decreasing resistance raises current. Capacitance deals with storing charge and isn’t what a rheostat uses to regulate current. Voltage is the driving force, but the rheostat’s job is to alter resistance to control how much current actually flows. So understanding that the device’s function is to adjust resistance makes the choice best.