Q. No.The power factor of a good choke coil is:
1. Nearly zero
2. Exactly zero
3. Nearly one
4. Exactly one
1. \(LC\)
2. \((LC)^{\frac{-1}{2}}\)
3. \(\left(\frac{L}{C}\right)^{\frac{-1}{2}}\)
4. \(\frac{C}{L}\)
| 1. | \(\frac{R}{4}\) |
| 2. | \(\frac{R}{2}\) |
| 3. | \(R\) |
| 4. | Cannot be found with the given data |
The phase difference between the current and voltage of LCR circuit in series combination at resonance is
1. 0
2. π/2
3. π
4. –π
In a series resonant circuit, the ac voltage across resistance R, inductance L and capacitance C are 5 V, 10 V and 10 V respectively. The ac voltage applied to the circuit will be
1. 20 V
2. 10 V
3. 5 V
4. 25 V
In a series LCR circuit, resistance R = 10Ω and the impedance Z = 20Ω. The phase difference between the current and the voltage is
1. 30°
2. 45°
3. 60°
4. 90°
In the circuit shown below, the AC source has voltage \(V = 20\cos(\omega t)\) volts with \(\omega =2000\) rad/sec. The amplitude of the current is closest to:
1. \(2\) A
2. \(3.3\) A
3. \(\frac{2}{\sqrt{5}}\)
4. \(\sqrt{5}~\text{A}\)
In an ac circuit the reactance of a coil is \(\sqrt{3}\) times its resistance, the phase difference between the voltage across the coil to the current through the coil will be:
1. \(
\pi / 3
\)
2. \( \pi / 2
\)
3. \( \pi / 4
\)
4. \( \pi / 6\)
The power factor of an ac circuit having resistance (R) and inductance (L) connected in series and an angular velocity ω is
1.
2.
3.
4.
An inductor of inductance \(L\) and resistor of resistance \(R\) are joined in series and connected by a source of frequency \(\omega\). The power dissipated in the circuit is:
| 1. | \(\dfrac{\left( R^{2} +\omega^{2} L^{2} \right)}{V}\) | 2. | \(\dfrac{V^{2} R}{\left(R^{2} + \omega^{2} L^{2} \right)}\) |
| 3. | \(\dfrac{V}{\left(R^{2} + \omega^{2} L^{2}\right)}\) | 4. | \(\dfrac{\sqrt{R^{2} + \omega^{2} L^{2}}}{V^{2}}\) |
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