The series combination of resistance R and inductance L is connected to an alternating source of e.m.f. E=311sin(100πt). If the peak value of wattless current is 0.5 A and the impedance of the circuit is 311 Ω, the power factor will be
Now we can write
and I0=E0Z=311311=1 A
Or,
∴sinϕ=12 or ϕ=30∘
Power factor
cosϕ=√32
Hence the power factor is √32