_____ is defined as the potential difference between two points of a conducting wire carrying a constant current of one amp when the power dissipated between these points is one watt.

_____ is defined as the potential difference between two points of a conducting wire carrying a constant current of one amp when the power dissipated between these points is one watt.

• A. Current
• B. Resistance
• C. Power
• D. Voltage

Answer: (D)

Voltage is the potential difference that drives current between two points. The power dissipated in a conductor is the product of voltage and current, P = V × I. With a current of 1 amp and power of 1 watt, the voltage is V = P / I = 1 W / 1 A = 1 volt. So the potential difference between the two points is 1 volt. This is exactly what voltage measures—the driving force for current. Note that current is the flow of charge, power is the rate of energy transfer, and resistance would be V/I = 1 V / 1 A = 1 ohm, but the question is asking for the potential difference, which is voltage.

Voltage is the potential difference that drives current between two points. The power dissipated in a conductor is the product of voltage and current, P = V × I. With a current of 1 amp and power of 1 watt, the voltage is V = P / I = 1 W / 1 A = 1 volt. So the potential difference between the two points is 1 volt. This is exactly what voltage measures—the driving force for current. Note that current is the flow of charge, power is the rate of energy transfer, and resistance would be V/I = 1 V / 1 A = 1 ohm, but the question is asking for the potential difference, which is voltage.