• question_answer A series combination of R, L and C is connected to an AC source. If the resistance is 30 and reactance is $4\Omega$. The power factor of the circuit is: A)  $0.4$                         B)  $0.6$C)  $0.8$                         D)  $1.0$

As, the power factor $\cos \,\phi =\frac{R}{Z}=\frac{R}{\sqrt{{{R}^{2}}+{{X}^{2}}}}\frac{3}{5}=0.6$ Here,            X= reactance = $4\Omega$