Ohm's law: a 5 Ω resistor carries 2 A. What is the voltage across it?

Ohm's law: a 5 Ω resistor carries 2 A. What is the voltage across it?

• A. 10 V
• B. 2 V
• C. 7 V
• D. 0.4 V

Answer: (A)

Voltage across a resistor comes from multiplying the current through it by its resistance: V = I × R. With a current of 2 A flowing through a 5 Ω resistor, the voltage is 2 × 5 = 10 V. So the voltage across it is 10 volts. The other options don’t fit these given values because they would require different current or resistance (for example, 2 V would need a different combination than 2 A through 5 Ω).

Voltage across a resistor comes from multiplying the current through it by its resistance: V = I × R. With a current of 2 A flowing through a 5 Ω resistor, the voltage is 2 × 5 = 10 V. So the voltage across it is 10 volts. The other options don’t fit these given values because they would require different current or resistance (for example, 2 V would need a different combination than 2 A through 5 Ω).