In a DC circuit, which statement best describes what determines the current with a given voltage and resistance?

In a DC circuit, which statement best describes what determines the current with a given voltage and resistance?

• A. The voltage of 28V only
• B. The resistance of 7Ω only
• C. Both the voltage and resistance, per Ohm's law
• D. The color of the wires

Answer: (C)

Ohm's law shows how current is set by voltage and resistance in a DC circuit: I = V / R. When both voltage and resistance are given, the current is determined by both values. You can’t find the current from voltage alone without knowing resistance, and you can’t find it from resistance alone without the voltage. If you increase the voltage while keeping the resistance the same, the current increases; if you increase the resistance with the same voltage, the current decreases. The color of the wires has no effect on the current in an ideal circuit. So the current depends on both the voltage and the resistance.

Ohm's law shows how current is set by voltage and resistance in a DC circuit: I = V / R. When both voltage and resistance are given, the current is determined by both values. You can’t find the current from voltage alone without knowing resistance, and you can’t find it from resistance alone without the voltage. If you increase the voltage while keeping the resistance the same, the current increases; if you increase the resistance with the same voltage, the current decreases. The color of the wires has no effect on the current in an ideal circuit. So the current depends on both the voltage and the resistance.