In an AC circuit, the current is given by; \(i=5\sin\left(100t-\frac{\pi}{2}\right)\) and the AC potential is \(V =200\sin(100 t)~\text V.\) The power consumption is:
1. \(20~\text W\)
2. \(40~\text W\)
3. \(1000~\text W\)
4. zero

Subtopic:  Power factor |
 86%
Level 1: 80%+
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In an \(LCR\) circuit having \(L = 8.0~\text{H}\), \(C= 0.5~\mu\text{F}\) and \(R = 100~\Omega\) in series, what is the resonance frequency?
1. \(600\) radian/sec
2. \(600\) Hz
3. \(500\) radian/sec
4. \(500\) Hz

Subtopic:  Different Types of AC Circuits |
 71%
Level 2: 60%+
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A circuit consists of \(3\) ohms of resistance and \(4\) ohms of reactance. The power factor of the circuit is:

1. \(0.4\) 2. \(0.6\)
3. \(0.8\) 4 \(1.0\)
Subtopic:  Power factor |
 77%
Level 2: 60%+
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The power factor of a good choke coil is:

1. Nearly zero

2. Exactly zero

3. Nearly one

4. Exactly one

Subtopic:  Power factor |
 56%
Level 3: 35%-60%
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In a series \(LCR\) circuit, resistance \(R=10~\Omega\) and the impedance \(Z=20~\Omega\). The phase difference between the current and the voltage will be:
1. \(30^{\circ}\)
2. \(45^{\circ}\)
3. \(60^{\circ}\)
4. \(90^{\circ}\)

Subtopic:  Different Types of AC Circuits |
 84%
Level 1: 80%+
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In the circuit shown in the figure, neglecting source resistance, the voltmeter and ammeter reading respectively will be:

          

1. \(0~\text{V}, 3~\text{A}\)
2. \(150~\text{V}, 3~\text{A}\)
3. \(150~\text{V}, 6~\text{A}\)
4. \(0~\text{V}, 8~\text{A}\)

Subtopic:  Different Types of AC Circuits |
 87%
Level 1: 80%+
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An AC source of variable frequency \(f\) is connected to an \(LCR\) series circuit. Which of the following graphs represents the variation of the current \(I\) in the circuit with frequency \(f\)?

1.   2.
3. 4.
Subtopic:  Different Types of AC Circuits |
 78%
Level 2: 60%+
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An inductor of \(20~\text{mH},\) a capacitor of \(50~ \mu \text{F},\) and a resistor of \(40~ \Omega\) are connected in series across a source of emf \(V= 10\sin340t\). What will be the power loss in the AC circuit?
1. \(0.67~\text{W}\) 2. \(0.78~\text{W}\)
3. \(0.89~\text{W}\) 4. \(0.46~\text{W}\)
Subtopic:  Power factor |
Level 3: 35%-60%
NEET - 2016
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A step–down transformer transforms a supply line voltage of \(2200\) volt into \(220\) volt. The primary coil has \(5000\) turns. The efficiency and power transmitted by the transformer are \(90\%\) and \(8\) kilowatts respectively. How many turns are there in the secondary one?
1. \(5000\)
2. \(50\)
3. \(500\)
4. \(5\)
Subtopic:  Transformer |
 82%
Level 1: 80%+
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Match List I (expression for current) with List II (rms value of current) and select the correct answer.

List I List II
(a) \(I=I_0 \sin \omega t \cos \omega t\) (i) \(I_0\)
(b) \(I=I_0 \sin \left(\omega t+\frac{\pi}{3}\right)\) (ii) \(I_0/\sqrt{2}\)
(c) \(I_0(\sin \omega t+\cos \omega t)\) (iii) \(I_0e\)
(d) \(I=I_0(e)\) (iv) \(I_0/2\sqrt{2}\)
 
A B C D
1. (iv) (ii) (i) (iii)
2. (iv) (ii) (iii) (i)
3. (ii) (iv) (iii) (i)
4. (ii) (iv) (i) (iii)
Subtopic:  RMS & Average Values |
 67%
Level 2: 60%+
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