Different Cases #8211; Case I : When AC circuit contains ohmic resistance. In this case, ɸ = 0. ∴ cosɸ = 1 ⇒ P<sub>ev</sub> = V<sub>rms</sub> times; I<sub>rms</sub> = V<sub>rms</sub> = V<sub>rms</sub> times; V<sub>rms</sub>/R = V<sup>2</sup><sub>rms</sub>/R, Case II : When AC circuit contains only capacitor. In this case, ɸ = -π/2 ∴ cosɸ = cos(-π/2) = 0 ⇒ P<sub>av</sub> = 0 Case III : When AC circuit contains only inductance. In this case, ɸ = π/2 ⇒ cosɸ = cosπ/2 = 0 Case IV : When AC circuit contains resistance and capacitance both. P<sub>av</sub> = V<sup>2</sup><sub>rms</sub> R/(R<sup>2</sup> + 1/⍵<sup>2</sup> C<sup>2</sup>) Case V : When AC circuit contains resistance and inductance both. P<sub>av</sub> = V<sup>2</sup><sub>rms</sub> R/(R<sup>2</sup> + ⍵L<sup>2</sup>) Case VI : When AC circuit contains inductance, capacitance and resistance. P<sub>av</sub> = V<sup>2</sup><sub>rms</sub>R/R<sup>2</sup> + (⍵L #8211; 1/⍵C)<sup>2</sup>