What is the value of inductance L for which the current is maximum in a series LCR circuit with C = 10 $$\mu $$F and $$\omega $$ = 1000 s^$$-$$1 ?

A transistor-oscillator using a resonant circuit with an inductor L (of negligible resistance) and a capacitor C in series produce oscillations of frequency $$f$$. If L is doubled and C is changed to 4C, the frequency will be

The core of a transformer is laminated because

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