A circuit draws a power of 550 W from a 220V-50 Hz source. The power factor of the circuit is 0.8. A current in the circuit lags behind the voltage. Show that a capacitor of about `1/(42pi)times10^-2F` will have to be connected in the circuit to bring its power factor to unity.

A circuit draws 280 W from a 110V, 60Hz ac line. The current lags the voltage and the power factor is 0.5. Find the value of a capacitance which can be connected in series to make the power factor of the circuit unity.

An alternating emf of E=20sin 1000tV is applied on a circuit containing a pure resistance of 25Omega in series with a coil of self-inductance 40 mH and resistance 15Omega . Find out the power factor of the circuit , Also , find out this capacitance of a capacitor that should be connected in series to raise the power factory to unity.

Without making any other change, find the value of the additional capacitor C_1 , to be connected in parallel with the capacitor C, in order to make the power factor of the circuit unity.

Power factor of an LR circuit is 1/sqrt2 . If the frequency of ac is doubled, what will be the power factor?

The frequency of applied of ac voltage to an inductive coil is 1000Hz.L=25 mH and the power factor of the circuit is 0.1.Find the resistance of the coil.

60muF capacitor to a 110 V, 60 Hz ac supply. Determine the rms value of the current in the circuit. What is the net power absorbed by the circuit over a complete cycle?

If an unregulated voltage of 10 V is regulated by a Zener diode of rating 4.7 V-1W calculate minimum resistance to be connected to the circuit for safe current.

An ac source is connected in series with an inductor of 5H and a resistor of 1000Omega . The rms value of voltage of the source is 100 V and the frequency of the source is 50cps. What is the rms value of the current in the circuit? What is the phase difference of the voltage and the current in the circuit? What is the power dissipated in the circuit?