Q. No.An ac source of variable frequency f is connected to an LCR series circuit. Which one of the graphs in the figure represents the variation of the current I in the circuit with frequency f :
1. 
2. 
3. 
4. 
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 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. \(\dfrac{I_0}{2}\)
3. \(\dfrac{2I_0 }{ \pi}\)
4. \(I_0\)
The current 'i' in an inductance coil varies with time 't' according to the following graph.
Which one of the following plots shows the variations of voltage in the coil?
1.
2.
3.
4.
When an AC source of emf \(e = E_0 \sin (100t)\) is connected across a circuit, the phase difference between the emf \(e\) 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. | \(R=1~\text{k} \Omega, C=10 ~\mu \text{F}\) |
| 2. | \(R=1~\text{k}\Omega, C=1~\mu \text{F}\) |
| 3. | \(R=1 ~\text{k}\Omega, L=10 ~\text{H}\) |
| 4. | \(R=1 ~\text{k}\Omega, L=1~\text{H}\) |
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. | \(0.4\) | \(-\pi/4\) |
| 2. | \(2.5\) | \(-\pi/2\) |
| 3. | \(2.5\) | \(+\pi/2\) |
| 4. | \(2.5\) | \(-\pi/4\) |
1. \(a\)
2. \(b\)
3. \(c\)
4. \(d\)
Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?
1.
2.
3.
4.
The potential differences across the resistance, capacitance and inductance are \(80\) V, \(40\) V and \(100\) V respectively in an \(LCR\) circuit.
What is the power factor of this circuit?
1. \(0.4\)
2. \(0.5\)
3. \(0.8\)
4. \(1.0\)
A 100 resistance and a capacitor of 100 reactance are connected in series across a 220 V source. When the capacitor is 50% charged, the peak value of the displacement current is
1. 2.2 A
2. 11A
3. 4.4A
4. 11A
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