From which of the following options can the power factor of an $AC$ circuit be zero?

The power factor of the circuit as shown in the figure is:

Define the power for $AC$ circuit. Obtain an equation of average power for $L-C-R$ series $AC$ circuit.

$A$ series $LCR$ circuit is connected to an $AC$ source of $220\,V, 50\,Hz$. The circuit contains a resistance $R = 80\,\Omega$,an inductor of inductive reactance $X_L = 70\,\Omega$,and a capacitor of capacitive reactance $X_C = 130\,\Omega$. The power factor of the circuit is $\frac{x}{10}$. The value of $x$ is:

An alternating supply of $220\,V$ is applied across a circuit with resistance $22\,\Omega$ and impedance $44\,\Omega$. The power dissipated in the circuit is.........$W$.

$A$ lamp consumes only $50 \%$ of maximum power in an $AC$ circuit. What is the phase difference between the applied voltage and the circuit current?