SSC JE Electrical Engineering 23 Jan 2018 Evening Paper

Tellegen's theorem is based on the principle of low of conservation of energy.
$\sum _{\mathit{k}=1}^{\mathit{n}}{\mathrm{V}}_{\mathit{k}}{\mathrm{I}}_{\mathit{k}}=0$
Tellegen's theorem states that sum of power delivered is zero for each branch of any electrical network at any instant of time.