A series R-C 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. 
Current through the resistor is I and the voltage across the capacitor is V then:

1. $V_a<V_b$

2. $V_a>V_b$

3. $i_a>i_b$

4. $V_a=V_b$

A resistance ' R' draws power 'P' when connected to an AC source. If an inductance is now placed in series with the resistance, such that the impedance of the circuit becomes 'Z', the power drawn will be:

1. \(P\Big({\large\frac{R}{Z}}\Big)^2\)

2. \(P\sqrt{\large\frac{R}{Z}}\)

3. \(P\Big({\large\frac{R}{Z}}\Big)\)

4. \(P\)

A transformer has an efficiency of \(90\)% working on \(200\) V and \(3\) kW power supply. If the current in the secondary coil is \(6\) A, the voltage across the secondary coil and the current in the primary coil, respectively, are:
1. \(300\) V, \(15\) A
2. \(450\) V, \(15\) A
3. \(450\) V, \(13.5\) A
4. \(600\) V, \(15\) A

In an electrical circuit \(R,\) \(L,\) \(C\) and an \(\mathrm{AB}\) voltage source are all connected in series. When \(L\) is removed from the circuit, the phase difference between the voltage and the current in the circuit is \(\tan^{-1}\sqrt{3}\). If instead, \(C\) is removed from the circuit, the phase difference is again \(\tan^{-1}\sqrt{3}\). The power factor of the circuit is:
1. \(1 / 2 \)
2. \(1 / \sqrt{2} \)
3. \(1 \)
4. \(\sqrt{3} / 2\)

The instantaneous values of alternating current and voltages in a circuit are given as,
\(i=\frac{1}{\sqrt{2}}sin\left ( 100\pi t \right )~Ampere\)
\(e=\frac{1}{\sqrt{2}}\left ( 100\pi t+\pi /3 \right )~Volt\)
What is the average power consumed by the circuit in watts?

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.  $\frac{\mathrm{\pi }}{4}$

2.  $\frac{\mathrm{\pi }}{2}$

3.  zero

4.  $\frac{\mathrm{\pi }}{6}$

The r.m.s. value of the potential difference V shown in the figure is:

1. ${\mathrm{V}}_0/\sqrt{3}$

2. ${\mathrm{V}}_0$

3. ${\mathrm{V}}_0/\sqrt{2}$

4. ${\mathrm{V}}_0/2$

A coil has a resistance of \(30~ \mathrm{ohm}\) and inductive reactance of \(20 ~\mathrm{ohm}\) at a \(50~\mathrm{ Hz}\) frequency. If an \(\mathrm{ac}\) source of \(200 ~\mathrm{volts,}\) \(100~\mathrm{ Hz}\) is connected across the coil, the current in the coil will be: