Which expression correctly defines electrical power using current and voltage?

Which expression correctly defines electrical power using current and voltage?

• A. I x E = P
• B. E / I = P
• C. P / I = E
• D. P = I / E

Answer: (A)

Power is the rate at which energy is transferred in a circuit. When current I flows through a voltage difference E, the energy transfer rate is given by P = I × E. This is the standard relation P = VI, so with voltage denoted as E, it becomes P = I × E. In watts, volts times amperes equals watts, which makes this form intuitive. You can rearrange the same equation to P/I = E (or E = P/I), but the direct and clearest expression for power in terms of current and voltage is P = I × E. The other forms would imply dividing by voltage or by current in ways that don’t match the power definition.

Power is the rate at which energy is transferred in a circuit. When current I flows through a voltage difference E, the energy transfer rate is given by P = I × E. This is the standard relation P = VI, so with voltage denoted as E, it becomes P = I × E. In watts, volts times amperes equals watts, which makes this form intuitive. You can rearrange the same equation to P/I = E (or E = P/I), but the direct and clearest expression for power in terms of current and voltage is P = I × E. The other forms would imply dividing by voltage or by current in ways that don’t match the power definition.