Which value equals the product of voltage and current in an electric circuit?

Which value equals the product of voltage and current in an electric circuit?

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

Answer: (D)

Power in an electrical circuit is the rate at which energy is transferred, and it equals the product of voltage and current. This means P = V × I, so the energy-per-second the circuit uses or delivers depends on both how strong the pushing force (voltage) and how much charge is moving (current). The resulting unit is watts, and 1 watt equals 1 volt × 1 ampere. For example, with 12 volts across a device drawing 2 amperes, the power is 24 watts. Voltage alone is just the potential difference, current alone is the flow of charge, and resistance relates voltage and current via V = IR or I = V/R; none of those are the product of voltage and current. The product VI accurately gives the power.

Power in an electrical circuit is the rate at which energy is transferred, and it equals the product of voltage and current. This means P = V × I, so the energy-per-second the circuit uses or delivers depends on both how strong the pushing force (voltage) and how much charge is moving (current). The resulting unit is watts, and 1 watt equals 1 volt × 1 ampere. For example, with 12 volts across a device drawing 2 amperes, the power is 24 watts. Voltage alone is just the potential difference, current alone is the flow of charge, and resistance relates voltage and current via V = IR or I = V/R; none of those are the product of voltage and current. The product VI accurately gives the power.