Different Types Of Ac Circuits

A transistor-oscillator using a resonant circuit with an inductance (of negligible resistance) and a capacitance has a frequency If is doubled and is changed to the frequency will be:
1.
2.
3.
4.

A coil of inductive reactance has a resistance of
. It is placed in series with a condenser of capacitive reactance . The combination is connected to an a.c. source of
. The power factor of the circuit is:
1.
2.
3.
4.

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?

1. 100 mH

2. 1 mH

3. cannot be calculated unless R is known

4. 10 mH

The power dissipated in an L-C-R series circuit connected to an AC source of emf E is:

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

1. 150 V, 2.2 A

2. 220 V, 2.2 A

3. 220 V, 2.0 A

4. 100 V, 2.0 A

An AC voltage is applied to a resistance R and an inductor L in series. If R and the inductive reactance are both equal to 3 $\Omega$, the phase difference between the applied voltage and the current in the circuit is:

1. $\frac{\mathrm{\backslash pi}}{4}$

2. $\frac{\mathrm{\backslash pi}}{2}$

3. zero

4. $\frac{\mathrm{\backslash pi}}{6}$

A series circuit is connected to an alternating voltage source. Consider two situations:
(1) When the capacitor is air-filled.
(2) When the capacitor is mica filled.
The current through the resistor is and the voltage across the capacitor is then:
1.
2.
3.
4.

Which of the following combinations should be selected for better tuning of an circuit used for communication?
1.
2.
3.
4.

A light bulb and an inductor coil are connected to an AC source through a key as shown in the figure below. The key is closed and after some time an iron rod is inserted into the interior of the inductor. The glow of the light bulb:

1.	decreases	2.	remains unchanged
3.	will fluctuate	4.	increases

An inductor of inductance , a capacitor of capacitance and a resistor of resistance are connected in series to an AC source of potential difference volts as shown in Figure. The potential difference across , and is , and , respectively. The amplitude of the current flowing through the series circuit is . The impedance of the circuit will be:

1.
2.
3.
4.

A series circuit containing inductor, capacitor and $\mathrm{}$ resistor is connected to variable frequency AC source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be:

1.
2.
3.
4.

A series circuit with inductance , capacitance , resistance is connected to an AC source of voltage, . If the resonant frequency of the circuit is and the frequency of the AC source is , then:

1.
2.
3.
4.

An AC source is connected to a capacitor . Due to decrease in its operating frequency:

1.	capacitive reactance remains constant
2.	capacitive reactance decreases.
3.	displacement current increases.
4.	displacement current decreases.

In a series circuit, the inductance is , capacitance is and resistance is . The frequency at which resonance occurs is:

1.		2.
3.		4.

The net impedance of the circuit (as shown in the figure) will be:

1.		2.
3.		4.

To an AC power supply of at a resistor of a capacitor of reactance and an inductor of reactance are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is, respectively:

1.		2.
3.		4.