If a conductor carries 2 A and has a resistance of 5 ohms, what is the voltage across it?

• A. 10 V
• B. 6 V
• C. 5 V
• D. 15 V

Answer: (A)

Ohm's law connects voltage, current, and resistance with V = I × R. With 2 A flowing through 5 Ω, the voltage is V = 2 × 5 = 10 volts. So the voltage across the conductor is 10 V. The other options would require different combinations: 6 V would come from 2 A with 3 Ω, 5 V from 2.5 Ω, and 15 V from 7.5 Ω.