For a fixed resistor, increasing current requires increasing which quantity?

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

Answer: (B)

Ohm’s law for a resistor says I = V / R. If the resistor is fixed, its resistance R stays constant. To increase the current I, you must increase the voltage V across the resistor, because I scales directly with V when R is unchanged. Doubling the voltage will roughly double the current in this ideal case.

Temperature can shift resistance a bit in real components, but that doesn’t reliably increase current through a fixed resistor; it may even reduce it if the resistance rises. Capacitance doesn’t set a steady DC current through a resistor—the capacitor mainly affects transient behavior or AC conditions, not the steady-state current for a fixed resistor. So the quantity you need to increase to drive more current is the voltage.