1. | \(\frac{1}{100}~\text{sec}\) | 2. | \(\frac{1}{200}~\text{sec}\) |
3. | \(\frac{1}{300}~\text{sec}\) | 4. | \(\frac{1}{400}~\text{sec}\) |
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. \(1.0\)
1. | Frequency of the AC source is decreased |
2. | The number of turns in the coil is reduced |
3. | A capacitance of reactance \(X_C = X_L\) is included in the same circuit |
4. | An iron rod is inserted in the coil |
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 \(3~ \Omega, \) then the phase difference between the applied voltage and the current in the circuit will be:
1. | \( \pi / 4\) | 2. | \( \pi / 2\) |
3. | zero | 4. | \( \pi / 6\) |
1. \(a\)
2. \(b\)
3. \(c\)
4. \(d\)
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. | \(2.5\) | \(-\pi/4\) |
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. | \(R=1 ~\text{k}\Omega, L=1~\text{H}\) |
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. | \(I_0 \over 2\) |
3. | \(2I_0 \over \pi\) | 4. | \(I_0\) |
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 \(\frac{\pi}{2}\). |
2. | The voltage leads the current by \(\frac{\pi}{2}\). |
3. | The voltage and the current are in phase. |
4. | The voltage leads the current by \(\pi\). |