Question

In which of the following circuits the maximum power dissipation is observed?

• A. Pure capacitive circuit
• B. Pure inductive circuit
• C. Pure resistive circuit
• D. None of these

Answer 1

The correct option is C Pure resistive circuit

In an AC circuit, the power dissipated in the circuit is given by:

$P=V_{rms}{I}_{rms}cos\varphi$

The $\varphi$ is the phase different between the current and the volatge.

In the purely resistive and capacitive circuits, the phase difference is ${90}^{\circ }$, so the power dissipated will be zero.

But in a purely resistive circuit, the voltage and current are in same phase so phase difference is zero. Therefore, it will have maximum power dissipation as $cos\varphi =1$ in this case.