In the diagram, two sinusoidal voltages of the same frequency are shown. What is the frequency and the phase relationship between the voltages?
      

	Frequency in Hz	Phase lead of N over M in radians
1.	0.4	–π/4
2.	2.5	–π/2
3.	2.5	+π/2
4.	2.5	–π/4

Which of the following plots may represent the reactance of a series of LC combinations?

1. a

2. b

3. c

4. d

In an ac circuit I= 100 sin 200 $\mathrm{\pi }$t. The time required for the current to reach its peak value will be:

1. \(\frac{1}{100}~sec\)
2. \(\frac{1}{200}~sec\)
3. \(\frac{1}{300}~sec\)
4. \(\frac{1}{400}~sec\)

The potential differences across the resistance, capacitance and inductance are 80 V, 40 V and 100 V respectively in an L-C-R circuit. What is the power factor of this circuit?

1. 0.4             

2. 0.5

3. 0.8             

4. 1.0

A coil of self-inductance L is connected in series with a bulb B and an AC source. The brightness of the bulb decreases when:

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 $\mathrm{3 }\mathrm{\Omega }$, then the phase difference between the applied voltage and the current in the circuit will be:

1. $\mathrm{\pi }/4$                                                
2. $\mathrm{\pi }/2$
3. zero                                                
4. $\mathrm{\pi }/6$

When an ac source of e.m.f. $e=E_0\sin \left(100t\right)$ is connected across a circuit, the phase difference between the e.m.f. e and the current i in the circuit is observed to be \(\frac{\pi}{4}\) as shown in the diagram. If the circuit consists only of RC or LC in series, then what is the relationship between the two elements?

1. $R=\mathrm{1 }k\Omega ,C=\mathrm{10 }\mu F$

2. $R=\mathrm{1 }k\Omega ,C=\mathrm{1 }\mu F$

3. $R=\mathrm{1 }k\Omega ,L=\mathrm{10 }H$

4. $R=\mathrm{1 }k\Omega ,L=\mathrm{1 }H$

The output current versus time curve of a rectifier is shown in the figure. The average value of the output current in this case will be:

1. 0
2. $\frac{I_0}{2}$
3. $\frac{2I_0}{\pi }$
4. I₀

A constant voltage at different frequencies is applied across a capacitance C as shown in the figure.
          
Which of the following graphs accurately illustrates how current varies with frequency?

1.		2.
3.		4.

The variation of the instantaneous current (I) and the instantaneous emf (E) in a circuit are shown in the figure. Which of the following statements is correct?

1. The voltage lags behind the current by π/2.

2. The voltage leads the current by π/2.

3. The voltage and the current are in phase.

4. The voltage leads the current by π.