A series LCR circuit is connected to an a.c. source of $230 \mathrm{~V}, 50 \mathrm{~Hz}$. The circuit contains resistance of $80 \Omega$ an inductor having inductive reactance $70 \Omega$ and a capacitor of capacitive reactance $130 \Omega$. The power factor of the circuit is $x$. The value of $x$ is

An alternating voltage $\mathrm{E}=100 \sqrt{2} \sin (50 \mathrm{t})$ is connected to a $2 \mu \mathrm{~F}$ capacitor through an a.c. ammeter. The ammeter reading will be

The instantaneous value of current in an a.c. circuit is $I=3 \sin \left(50 \pi t+\frac{\pi}{4}\right) \mathrm{A}$. The current will be maximum for the first time at