Alternating Current

In the given circuit the reading of voltmeter V1 and V2 are 300 volts each. The reading of the voltmeter V3 and ammeter A are respectively

A condenser of capacity C is charged to a potential difference of V1. The plates of th condenser are then connected to an ideal inductor of inductance L. The current through the inductor when the potential difference across the condenser re...

Power dissipated in an LCR series circuit connected to an A.C. source of emf \(\varepsilon\) is

In an a.c. circuit the e.m.f. (\(\varepsilon\)) and the current
(i)  at any instant are given respectively by
\(\varepsilon\) = E0sin\(\omega\)t,   \(i\) = \(I\)0sin(\(\omega\)t \(-\) \(\phi\))
The average power in the circuit over o...

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 ?

The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux \(\phi\) linked with the primary coil is given by \(\phi\) = \(\phi\)0 + 4t, where \(\phi\) is webers, t is time in seconds and $...

A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 amp, the efficiency of the transformer is approximately

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 t...

The core of a transformer is laminated because

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

In a circuit L, C and R are connected in series with an alternating voltage source of frquency \(f.\) The current leads the voltage by 45o. The value of C is

A coil of 40 henry inductance is connected in series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is

For a series LCR circuit the power loss at resonance is

The value of quality factor is

A capacitor of capacity C has reactance X. If capacitance and frequency become double then reactance will be