What is the formula for electrical power in terms of voltage and current?

• A. P = I × R
• B. P = V × I
• C. P = V × R
• D. P = V^2 / R

Answer: (B)

Power is the rate at which electrical energy is delivered or used. When you know the voltage across a component and the current flowing through it, the power is simply the product of voltage and current: P = V × I. This direct relationship ties the driving force (voltage) to how much charge is moving per second (current), giving energy per second.

From Ohm's law, you can derive alternative forms like P = I^2 × R or P = V^2 / R, which show how resistance also influences power. But for a direct expression using voltage and current, the simplest form is P = V × I. The other options involve mixing in resistance in ways that aren’t the straightforward voltage–current product, though they can be related through substitution.