An alternating voltage = 200 $$\sin 100t$$ is applied to a series combination of $$R=30\Omega$$ and an inductor of 400 mH. The power factor of the circuit is,

The AC voltage across a resistance can be measured using a

The formula of capacitative reactance is

For the same resonant frequency, if L is changed from L to $${L \over 3}$$, then capacitance should change from C to