Two heater wires of identical length and material but different thicknesses are joined in series across a supply. In which wire is more power dissipated?

Equal in both
More in the thinner wire
More in the thicker wire
Cannot be determined

Correct answer: More in the thinner wire

Solution

Same length and material means R is inversely proportional to area; the thinner wire has higher R and, with equal series current, dissipates more power (P = I² R).

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