An inductor of \(20~\text{mH},\) a capacitor of \(50~ \mu \text{F},\) and a resistor of \(40~ \Omega\) are connected in series across a source of emf \(V= 10\sin340t\). What will be the power loss in the AC circuit?

1.	\(0.67~\text{W}\)	2.	\(0.78~\text{W}\)
3.	\(0.89~\text{W}\)	4.	\(0.46~\text{W}\)

The rms value of potential difference V shown in the figure is

(1) ${\mathrm{V}}_{\mathrm{o}}$                                                     

(2) $\frac{{\mathrm{V}}_{\mathrm{o}}}{\sqrt{2}}$

(3)$\frac{{\mathrm{V}}_{\mathrm{o}}}{2}$                                                     

(4) $\frac{{\mathrm{V}}_{\mathrm{o}}}{\sqrt{3}}$   

A coil has resistance $30 \mathrm{\Omega }$ and inductive reactance $20 \mathrm{\Omega }$ at 50 Hz frequency. If an AC source of 200 V, 100 Hz, is connected across the coil, the current in the coil will be:

 1. $4.0 \mathrm{A}$                                          

 2. $8.0 \mathrm{A}$

 3. $\frac{20}{\sqrt{13}}\mathrm{A}$                                         

 4. $2.0 \mathrm{A}$

Power dissipated in an L-C-R series circuit connected to an AC source of emf $\epsilon$ is 

(a) $\frac{{\epsilon }^{2}R}{\left[{\displaystyle R^2+{\left(L\omega -\frac{1}{C\omega }\right)}^2}\right]}$

(b) $\frac{{\epsilon }^2{\sqrt{R^2+\left(L\omega -{\displaystyle \frac{1}{C\omega }}\right)}}^2}{R}$

(c) $\frac{{\epsilon }^2\left[R^2+{\left(L\omega -{\displaystyle \frac{1}{C\omega }}\right)}^2\right]}{R}$

(d) $\frac{{\epsilon }^{2}R}{\sqrt{R^2+{\left(L\omega -{\displaystyle \frac{1}{C\omega }}\right)}^2}}$

The natural frequency of the circuit shown in the figure is:
    

1. $\frac{1}{2\mathrm{\pi }\sqrt{\mathrm{LC}}}$

2. $\frac{1}{\mathrm{\pi }\sqrt{\mathrm{LC}}}$

3. $\frac{2}{\mathrm{\pi }\sqrt{\mathrm{LC}}}$

4. None of these

The root-mean-square value of an alternating current of 50 Hz frequency is 10 A. The time taken by  the alternating current in reaching from zero to maximum value and peak value will be:

(1) 2×10^–2 s and 14.14 A            (2)  1 × 10^–2 s and 7.07 A

(3) 5×10^–3 s and 7.07 A              (4) 5 × 10^–3 s and 14.14 A

Match List I (expression for current) with List II (rms value of current) and select the correct answer.

Turn ratio in a step-up transformer is 1: 2 if a
Lechlanche cell of 1.5 V is connected across the
input, then the voltage across the output will be:

1. 0.1 V     

2. 1.5 V 

3. 0.75 V 

4. zero

In an ideal parallel LC circuit, the capacitor is
charged by connecting it to a D.C. source which
is then disconnected. The current in the circuit:

1. becomes zero instantaneously 
2. grows monotonically
3. decays monotonically
4. oscillates instantaneously