Which equation is used to define resistance?
Correct answer: C. Potential difference = current × resistance
- A. Energy = (current)2 × resistance × time
- B. Power = (currency)2 × resistance
- C. Potential difference = current × resistance
- D. Resistivity = resistance × area + length
Explanation
Ohm's Law states that the potential difference (voltage) across a conductor is directly proportional to the current flowing through it, with the proportionality factor being the resistance. This relationship is expressed as V = IR, where V is voltage, I is current, and R is resistance. Therefore, Option C correctly represents this relationship.Options A and B refer to formulas for energy and power dissipation in resistors, but they do not define resistance as per Ohm's Law. Option D incorrectly attempts to mix concepts of resistivity and resistance, and does not align with Ohm's Law.
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Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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