Ohm's law states that, at constant temperature, the current through a conductor is
- A. inversely proportional to the potential difference across it
- B. directly proportional to the potential difference across it
- C. independent of the potential difference
- D. proportional to the square of the potential difference
Explanation
A graph of current against voltage for an ohmic conductor is a straight line through the origin whose gradient is the reciprocal of the resistance. The condition of constant temperature matters, since a filament lamp heats up as the current rises and its graph curves. Semiconductor diodes are non ohmic for a different reason, conducting in one direction only.
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