Physics Resistance Problem

The resistance in the circuit on the right (R_r) is twice that of the circuit on the left (R), so the current (I_r) is half that of the left circuit (I).  Power dissipated is equal to I_r²*R_r , so the power dissipated in the right circuit is given by:  P_r = (I/2)²*(2R)

so P_r = I²*R/2,  but P = I²*R  so P_r = P/2

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