A circuit consists of $3$ ohms of resistance and $4$ ohms of reactance. The power factor of the circuit is:

The power factor of a good choke coil is:

1. Nearly zero

2. Exactly zero

3. Nearly one

4. Exactly one

The phase difference between the current and voltage of LCR circuit in series combination at resonance is 

(1) 0

(2) π/2

(3) π

(4) –π

In a series $LCR$ circuit, resistance $R=10~\Omega$ and the impedance $Z=20~\Omega$. The phase difference between the current and the voltage will be:
1. $30^{\circ}$
2. $45^{\circ}$
3. $60^{\circ}$
4. $90^{\circ}$

The power factor of an ac circuit having resistance (R) and inductance (L) connected in series and an angular velocity ω is 

(1) $R/\omega L$

(2) $R/{(R^2+{\omega }^2{L}^2)}^{1/2}$

(3) $\omega L/R$

(4) $R/{(R^2-{\omega }^2{L}^2)}^{1/2}$

In an LR-circuit, the inductive reactance is equal to the resistance R of the circuit. An e.m.f. $E=E_0\cos \left(\omega t\right)$ applied to the circuit. The power consumed in the circuit is:

(1) $\frac{E_0^2}{R}$

(2) $\frac{E_0^2}{2R}$

(3) $\frac{E_0^2}{4R}$

(4) $\frac{E_0^2}{8R}$

In the circuit shown in the figure, neglecting source resistance, the voltmeter and ammeter reading respectively will be:

1. $0~\text{V}, 3~\text{A}$
2. $150~\text{V}, 3~\text{A}$
3. $150~\text{V}, 6~\text{A}$
4. $0~\text{V}, 8~\text{A}$

An AC source of variable frequency $f$ is connected to an $LCR$ series circuit. Which of the following graphs represents the variation of the current $I$ in the circuit with frequency $f$?

1.		2.
3.		4.

Which of the following plots may represent the reactance of a series LC combination 

(1) a

(2) b

(3) c

(4) d