In an $AC$ circuit,current is $3 \ A$,voltage is $210 \ V$,and power is $63 \ W$. The power factor is . . . . . . .

The $r.m.s.$ current in an $AC$ circuit is $2 \ A$. If the wattless current is $\sqrt{3} \ A$,what is the power factor?

$A$ coil of inductive reactance $31\,\Omega$ has a resistance of $8\,\Omega$. It is placed in series with a capacitor of capacitive reactance $25\,\Omega$. The combination is connected to an $A$.$C$. source of $110\,V$. The power factor of the circuit is:

When a voltage $V = V_0 \cos \omega t$ is applied across a resistor of resistance $R$,the average power dissipated per cycle in the resistor is given by

In an $A.C.$ circuit,$V$ and $I$ are given by:
$V = 100 \sin(100 t) \text{ V}$
$I = 100 \sin(100 t + \pi/3) \text{ mA}$
The power dissipated in the circuit is:

Can the instantaneous power output of an $AC$ source ever be negative? Can the average power output be negative?