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

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Prepare for the Electrical Academy Level 1 Test. Study with multiple choice questions, flashcards, and detailed explanations. Assess your knowledge and ace the exam!

Multiple Choice

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

Explanation:
Power is the rate at which electrical energy is transferred to a component. For a resistor, the current through it is I = V / R by Ohm’s law. The power delivered to that resistor is P = V × I. Substituting I gives P = V × (V / R) = V^2 / R. So, when you know the voltage across a component and its resistance, the power is P = V^2 / R. This also aligns with the other equivalent forms, like P = VI or P = I^2R, which are just different ways to write the same relationship using Ohm’s law. The form P = V^2 would not generally represent power, since it lacks the division by resistance.

Power is the rate at which electrical energy is transferred to a component. For a resistor, the current through it is I = V / R by Ohm’s law. The power delivered to that resistor is P = V × I. Substituting I gives P = V × (V / R) = V^2 / R. So, when you know the voltage across a component and its resistance, the power is P = V^2 / R. This also aligns with the other equivalent forms, like P = VI or P = I^2R, which are just different ways to write the same relationship using Ohm’s law. The form P = V^2 would not generally represent power, since it lacks the division by resistance.

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