Find VC if element C generates 3W of power

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Direction: Statement for Q. 10 to Q. 15.
In the circuit shown below, the voltages, currents and powers of some elements have been measured.

Find V_C if element C generates 3W of power—

1. + 1V
2. 9V
3. – 1V
4. – 9V

Correct Option: C

The element C generated 3W of power. However from the given circuit current enters at the positive terminal it means current is negative or we can say power is negative i.e.,

P_C = – V_C × I_C
or
3W = – V_C × 3A
or
V_C = – 1V