Question

Obtain an expression of average power for alternating circuit, whenever pure resistance in circuit.

Answer 1

Average power dissipated in an RLC circuit is given by $P_{avg}=V_{rms}{I}_{rms}\cos \varphi$
where $\cos \varphi =\frac{R}{Z}$
In pure resistive circuit, impedence $Z=R$
$⟹P_{avg}=V_{rms}{I}_{rms}$
Also, we know that $V_{rms}=I_{rms}Z=I_{rms}R$ $(\because Z=R)$
$⟹P_{avg}=I_{rms}^{2}R$