Which equation correctly expresses electrical power?

Which equation correctly expresses electrical power?

• A. Amps x Volts
• B. Volts x Ohms
• C. Joules x Seconds
• D. Watts x Seconds

Answer: (A)

Power is the rate at which electrical energy is transferred, so it comes from multiplying the amount of current by the voltage. When you multiply current in amperes by voltage in volts, you get power in watts. This is because watts are defined as joules per second, and amperes times volts simplifies to joules per second. So the correct form is current times voltage. For example, if you have 2 A at 5 V, the power is 2 × 5 = 10 watts, the rate at which energy is being transferred. The other expressions don’t describe power directly. Volts times ohms isn’t a standard expression for power (ohms relate current and voltage, and power can be expressed as I²R or V²/R). Joules times seconds is energy times time, not a rate. Watts times seconds gives energy, not power.

Power is the rate at which electrical energy is transferred, so it comes from multiplying the amount of current by the voltage. When you multiply current in amperes by voltage in volts, you get power in watts. This is because watts are defined as joules per second, and amperes times volts simplifies to joules per second.

So the correct form is current times voltage. For example, if you have 2 A at 5 V, the power is 2 × 5 = 10 watts, the rate at which energy is being transferred.

The other expressions don’t describe power directly. Volts times ohms isn’t a standard expression for power (ohms relate current and voltage, and power can be expressed as I²R or V²/R). Joules times seconds is energy times time, not a rate. Watts times seconds gives energy, not power.