Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then in parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combination would be:

Suppose the resistance of each one of the two wires is R.

Case (i) When both wires are connected in series. Then, net resistance will be R+
R = 2R.


Then, heat produced will be


Case (ii) When both wires are connected in parallel. Then, net resistance will be


Then, heat produced will be


Now, The ratio will be


Thus, option (d) is correct.

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