Which statement best defines electrical power in a DC circuit?

Which statement best defines electrical power in a DC circuit?

• A. The energy stored in a capacitor.
• B. The rate of doing work; P = V × I.
• C. Power equals voltage divided by resistance.
• D. Power is independent of current.

Answer: (B)

Power in a DC circuit is the rate at which electrical energy is delivered or converted. It is defined by the product of voltage and current: P = V × I. This means how much energy per second is transferred to or from a component. For example, with 12 volts across a load drawing 2 amperes, the power is 24 watts, so 24 joules of energy pass per second. The energy stored in a capacitor is not power; it’s energy stored in the electric field, given by a different expression. You can also relate power to resistance using Ohm’s law: P = I^2 R or P = V^2 / R, but the fundamental relationship is P = V × I. Power depends on current, so saying it’s independent of current isn’t correct. The statement P = V / R would give current (I = V/R), not power.

Power in a DC circuit is the rate at which electrical energy is delivered or converted. It is defined by the product of voltage and current: P = V × I. This means how much energy per second is transferred to or from a component. For example, with 12 volts across a load drawing 2 amperes, the power is 24 watts, so 24 joules of energy pass per second.

The energy stored in a capacitor is not power; it’s energy stored in the electric field, given by a different expression. You can also relate power to resistance using Ohm’s law: P = I^2 R or P = V^2 / R, but the fundamental relationship is P = V × I. Power depends on current, so saying it’s independent of current isn’t correct. The statement P = V / R would give current (I = V/R), not power.