Key Idea: The power is defined as the rate at which work is being done in the circuit. Power = rate of work done in one complete cycle. Paν=TWPaν=T(E0I0cosϕ)T/2Paν=2E0I0cosϕ where cosϕ is called the power factor of an AC circuit.
In an AC circuit the emf (e) and the current (i) at any instant are given respectively by e=E0sinωt i=I0sin(ωt−ϕ) The average power in the circuit over one cycle of AC is
Held on 30 Apr 2008 · Verified 9 Jul 2026.
2E0I0
2E0I0sinϕ
2E0I0cosϕ
E0I0
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