In series LCR circuit R $=18 \Omega$ and impedance is $30 \Omega$. An rms voltage 210 V is applied across the circuit. The true power consumed in AC circuit is nearly

A resistor of $5 . \Omega$, inductor of self inductance $\left(\frac{2}{\pi^2}\right) \mathrm{H}$ and a capacitor of unknown capacity are connected in series to an a.c. source of $100 \mathrm{~V}, 50 \mathrm{~Hz}$ supply. When the voltage and current are in phase, the value of capacitance is

$\mathrm{L}, \mathrm{C}$ and R are connected in series to an a. c. source. Which one of the following is true?

Phase relation between current and voltage is such that

In series LCR circuit C $=2 \mu \mathrm{~F}, \mathrm{~L}=5 \mathrm{mH}$ and $\mathrm{R}=5 \Omega$. The ratio of energy stored in the inductor to that in capacitor, when maximum current flows through the circuit is