A DC circuit has a 10 m run of conductors with resistance 0.02 Ω/m and carries 5 A. What is the voltage drop across the run?

A DC circuit has a 10 m run of conductors with resistance 0.02 Ω/m and carries 5 A. What is the voltage drop across the run?

• A. 0.5 V
• B. 2 V
• C. 5 V
• D. 1 V

Answer: (D)

Voltage drop in a DC conductor follows V = I × R. The total resistance of the 10 m run is its length times resistance per meter: 10 m × 0.02 Ω/m = 0.2 Ω. With a current of 5 A, the drop is V = 5 A × 0.2 Ω = 1 V. So the voltage drop across the run is 1 volt. The other numbers would require different total resistance (for example, 0.4 Ω for 2 V, or 1 Ω for 5 V), which isn’t the case here.

Voltage drop in a DC conductor follows V = I × R. The total resistance of the 10 m run is its length times resistance per meter: 10 m × 0.02 Ω/m = 0.2 Ω. With a current of 5 A, the drop is V = 5 A × 0.2 Ω = 1 V. So the voltage drop across the run is 1 volt. The other numbers would require different total resistance (for example, 0.4 Ω for 2 V, or 1 Ω for 5 V), which isn’t the case here.