Which formula correctly defines electrical power in a DC circuit?

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

Answer: (B)

Power is the rate at which energy is transferred in a circuit. In a DC circuit this rate comes from how much energy per charge (voltage) and how many charges per second (current) are moving. The direct way to express that is P = V × I, which gives power in watts. You can also get power from P = I^2R or P = V^2/R if you know resistance and use Ohm’s law (V = IR), but the fundamental definition remains P = VI. The other formulas in the options don’t define power: V ÷ I gives resistance, not power; I × R is not the general power expression unless you substitute R; and V^2 alone isn’t power without multiplying by a current or applying the proper context.