The value of the quality factor is:
1. ωLR

2. ωRC

3. LC

4. L/R

Subtopic:  Different Types of AC Circuits |
 79%
Level 2: 60%+
AIPMT - 2000
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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 \(C\) is:
1. \(\frac{1}{2 \pi f(2 \pi f L-R)}\)
2. \(\frac{1}{2\pi f(2 \pi f L+R)}\)
3. \(\frac{1}{ \pi f(2 \pi f L-R)}\)
4. \(\frac{1}{\pi f(2 \pi f L+R)}\)

Subtopic:  Different Types of AC Circuits |
 62%
Level 2: 60%+
AIPMT - 2005
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Turn ratio of a step-up transformer is \(1: 25\). If current in load coil is \(2~\text{A}\), then the current in primary coil will be:

1. \(25~\text{A}\) 2. \(50~\text{A}\)
3. \(0.25~\text{A}\) 4. \(0.5~\text{A}\)
Subtopic:  Transformer |
 89%
Level 1: 80%+
AIPMT - 1998
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A coil of \(40\) H inductance is connected in series with a resistance of \(8~\Omega\) and the combination is joined to the terminals of a \(2~\text{V}\) battery. The time constant of the circuit is:
1. \(1/5~\text{s}\)
2. \(40~\text{s}\)
3. \(20~\text{s}\)
4. \(5~\text{s}\)

Subtopic:  Different Types of AC Circuits |
 70%
Level 2: 60%+
AIPMT - 2004
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For a series \(\mathrm{LCR}\) circuit, the power loss at resonance is:
1. \(\frac{V^2}{\left[\omega L-\frac{1}{\omega C}\right]}\)

2. \( \mathrm{I}^2 \mathrm{~L} \omega \)

3. \(I^2 R\)

4. \( \frac{\mathrm{V}^2}{\mathrm{C} \omega} \)

Subtopic:  Power factor |
 81%
Level 1: 80%+
AIPMT - 2002
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A capacitor of capacity \(C\) has reactance \(X\). If capacitance and frequency are doubled, then the reactance will be:
1. \(4X\)
2. \(\frac{X}{2}\)
3. \(\frac{X}{4}\)
4. \(2X\)

Subtopic:  Different Types of AC Circuits |
 82%
Level 1: 80%+
AIPMT - 2001
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An inductor of inductance \(L\), a capacitor of capacitance \(C\) and a resistor of resistance \(R\) are connected in series to an AC source of potential difference \(V\) volts as shown in Figure. The potential difference across \(L\), \(C\) and \(R\) is \(40~\text{V}\), \(10~\text{V}\) and \(40~\text{V}\), respectively. The amplitude of the current flowing through the \(LCR\) series circuit is \(10\sqrt{2}~\text{A}\). The impedance of the circuit will be:

      

1. \(4~\Omega\) 2. \(5~\Omega\)
3. \(4\sqrt{2}~\Omega\) 4. \(\dfrac{5}{\sqrt{2}}~\Omega\)
Subtopic:  Different Types of AC Circuits |
Level 3: 35%-60%
NEET - 2021
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A step-down transformer connected to an AC mains supply of \(220~\text{V}\) is made to operate at \(11~\text{V},\) \(44~\text{W}\) lamp. Ignoring power losses in the transformer, what is the current in the primary circuit?
1. \(2~\text{A}\)
2. \(4~\text{A}\)
3. \(0.2~\text{A}\)
4. \(0.4~\text{A}\)
Subtopic:  Transformer |
 70%
Level 2: 60%+
NEET - 2021
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A series \(LCR\) circuit containing \(5.0~\text{H}\) inductor, \(80~\mu \text{F}\) capacitor and \(40~\Omega\) resistor is connected to \(230~\text{V}\) variable frequency AC source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be:

1. \(46~\text{rad/s}~\text{and}~54~\text{rad/s}\)
2. \(42~\text{rad/s}~\text{and}~58~\text{rad/s}\)
3. \(25~\text{rad/s}~\text{and}~75~\text{rad/s}\)
4. \(50~\text{rad/s}~\text{and}~25~\text{rad/s}\)

Subtopic:  Different Types of AC Circuits |
Level 3: 35%-60%
NEET - 2021
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A coil has a resistance of \(30~ \text{ohm}\) and inductive reactance of \(20 ~\text{ohm}\) at a \(50~\text{Hz}\) frequency. If an \(AC\) source of \(200~\text{volts,}\) \(100~\text{Hz}\) is connected across the coil, the current in the coil will be:
1. \(2.0~\text{A}\) 2. \(4.0~\text{A}\)
3. \(8.0~\text{A}\) 4. \(20/\sqrt{13}~\text{A}\)
Subtopic:  Different Types of AC Circuits |
 63%
Level 2: 60%+
AIPMT - 2011
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