- 1(current)
Q. No.| 1. | resistive circuit | 2. | \({LC}\) circuit |
| 3. | inductive circuit | 4. | capacitive circuit |
An AC source given by \(V=V_m\sin(\omega t)\) is connected to a pure inductor \(L\) in a circuit and \(I_m\) is the peak value of the AC current. The instantaneous power supplied to the inductor is:
| 1. | \(\dfrac{V_mI_m}{2}\mathrm{sin}(2\omega t)\) | 2. | \(-\dfrac{V_mI_m}{2}\mathrm{sin}(2\omega t)\) |
| 3. | \({V_mI_m}\mathrm{sin}^{2}(\omega t)\) | 4. | \(-{V_mI_m}\mathrm{sin}^{2}(\omega t)\) |
An AC voltage source is connected to a series \(LCR\) circuit. When \(L\) is removed from the circuit, the phase difference between current and voltage is \(\dfrac{\pi}{3}\). If \(C\) is instead removed from the circuit, the phase difference is again \(\dfrac{\pi}{3}\) between current and voltage. The power factor of the circuit is:
1. \(0.5\)
2. \(1.0\)
3. \(-1.0\)
4. zero
An inductor of \(20~\text{mH}\), a capacitor of \(100~\mu \text{F}\), and a resistor of \(50~\Omega\) are connected in series across a source of emf, \(V=10 \sin (314 t)\). What is the power loss in this circuit?
1. \( 0.79 ~\text{W} \)
2. \( 0.43 ~\text{W} \)
3. \( 2.74 ~\text{W} \)
4. \( 1.13 ~\text{W}\)
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. | over a full cycle, the capacitor \(C\) does not consume any energy from the voltage source. |
| 2. | current \(I(t)\) is in phase with voltage \(V(t)\). |
| 3. | current \(I(t)\) leads voltage \(V(t)\) by \(180^{\circ}\). |
| 4. | current \(I(t)\), lags voltage \(V(t)\) by \(90^{\circ}\). |
| 1. | \(0.67~\text{W}\) | 2. | \(0.76~\text{W}\) |
| 3. | \(0.89~\text{W}\) | 4. | \(0.51~\text{W}\) |
- 1(current)
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