Q. No.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. \( \pi / 6\)
1. \( \pi / 3 \)
2. \( \pi / 2 \)
3. \( \pi / 4 \)
4. \( \pi / 6\)
The capacity of a pure capacitor is 1 farad. In dc circuits, its effective resistance will be
(1) Zero
(2) Infinite
(3) 1 ohm
(4) 1/2 ohm
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. | \(\dfrac{\sqrt{R^{2} + \omega^{2} L^{2}}}{V^{2}}\) |
In an \(LCR\) circuit, the potential difference between the terminals of the inductance is \(60\) V, between the terminals of the capacitor is \(30\) V and that between the terminals of the resistance is \(40\) V. The supply voltage will be equal to:
1. \(50\) V
2. \(70\) V
3. \(130\) V
4. \(10\) V
In a circuit, \(L, C\) and \(R\) are connected in series with an alternating voltage source of frequency \(f.\) The current leads the voltage by \(45^{\circ}\). The value of \(C\) will be:
| 1. | \(\dfrac{1}{2 \pi f \left( 2 \pi f L + R \right)}\) | 2. | \(\dfrac{1}{\pi f \left(2 \pi f L + R \right)}\) |
| 3. | \(\dfrac{1}{2 \pi f \left( 2 \pi f L - R \right)}\) | 4. | \(\dfrac{1}{\pi f \left(2 \pi f L - R \right)}\) |
For the series LCR circuit shown in the figure, what is the resonance frequency and the amplitude of the current at the resonating frequency ?
1. 2500 rad/s and
2. 2500 rad/s and 5A
3. 2500 rad/s and
4. 25 rad/s and
In an LR-circuit, the inductive reactance is equal to the resistance R of the circuit. An e.m.f. applied to the circuit. The power consumed in the circuit is:
(1)
(2)
(3)
(4)
One 10 V, 60 W bulb is to be connected to 100 V line. The required induction coil has a self-inductance of value: (f = 50 Hz)
(1) 0.052 H
(2) 2.42 H
(3) 16.2 mH
(4) 1.62 mH
In the circuit given below, what will be the reading of the voltmeter
(1) 300 V
(2) 900 V
(3) 200 V
(4) 400 V
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