A series R-C circuit is connected to an alternating voltage source. Consider two situations:

 
1) When the capacitor is air-filled. 
2) When the capacitor is mica filled. 
Current through the resistor is I and the voltage across the capacitor is V then:

1. Va<Vb

2. Va>Vb

3. ia>ib

4. Va=Vb

Subtopic:  Different Types of AC Circuits |
 67%
From NCERT
NEET - 2015
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A resistance ' R' draws power 'P' when connected to an AC source. If an inductance is now placed in series with the resistance, such that the impedance of the circuit becomes 'Z', the power drawn will be:

1. \(P\Big({\large\frac{R}{Z}}\Big)^2\)

2. \(P\sqrt{\large\frac{R}{Z}}\)

3. \(P\Big({\large\frac{R}{Z}}\Big)\)

4. \(P\)

Subtopic:  Power factor |
 62%
From NCERT
NEET - 2015
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A transformer has an efficiency of \(90\)% working on \(200\) V and \(3\) kW power supply. If the current in the secondary coil is \(6\) A, the voltage across the secondary coil and the current in the primary coil, respectively, are:
1. \(300\) V, \(15\) A
2. \(450\) V, \(15\) A
3. \(450\) V, \(13.5\) A
4. \(600\) V, \(15\) A

Subtopic:  Transformer |
 77%
From NCERT
AIPMT - 2014
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The primary of a transformer when connected to dc battery of \(10\) Volt draws a current of \(1~\mathrm{mA}\). The number of turns of the primary and secondary windings are 50 and 100 respectively. The voltage in the secondary and the current drawn by the circuit in the secondary are respectively:
1. \(20~\mathrm{V}\)  and \(2.0~\mathrm{mA}\)
2. \(10~\mathrm{V}\) and \(0.5~\mathrm{mA}\)
3. zero and therefore no current
4. \(20~\mathrm{V}\) and \(0.5~\mathrm{mA}\)

 
Subtopic:  Transformer |
From NCERT
NEET - 2013
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In an electrical circuit \(R,\) \(L,\) \(C\) and an \(\mathrm{AB}\) voltage source are all connected in series. When \(L\) is removed from the circuit, the phase difference between the voltage and the current in the circuit is \(\tan^{-1}\sqrt{3}\). If instead, \(C\) is removed from the circuit, the phase difference is again \(\tan^{-1}\sqrt{3}\). The power factor of the circuit is:
1. \(1 / 2 \)
2. \(1 / \sqrt{2} \)
3. \(1 \)
4. \(\sqrt{3} / 2\)

Subtopic:  Power factor |
 81%
From NCERT
AIPMT - 2012
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The instantaneous values of alternating current and voltages in a circuit are given as,
\(i=\frac{1}{\sqrt{2}}sin\left ( 100\pi t \right )~Ampere\)
\(e=\frac{1}{\sqrt{2}}\left ( 100\pi t+\pi /3 \right )~Volt\)
What is the average power consumed by the circuit in watts?

1. \( \frac{\sqrt{3}}{4} \) 2. \( \frac{1}{2} \)
3. \( \frac{1}{8} \) 4. \( \frac{1}{4}\)
Subtopic:  Power factor |
 74%
From NCERT
AIPMT - 2012
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In an AC circuit, an alternating voltage \(\varepsilon=200 \sqrt{2} \sin (100 t)~\text{V}\) is connected to a capacitor of capacity \(1~\mu \text{F}.\) The RMS value of the current in the circuit is:
1. \(100~\text{mA}\) 
2. \(200~\text{mA}\)
3. \(20~\text{mA}\)
4. \(10~\text{mA}\)
Subtopic:  RMS & Average Values | Different Types of AC Circuits |
 76%
From NCERT
AIPMT - 2011
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An AC voltage is applied to a resistance R and an inductor L in series. If R and the inductive reactance are both equal to 3 Ω, the phase difference between the applied voltage and the current in the circuit is:

1.  π4

2.  π2

3.  zero

4.  π6

Subtopic:  Different Types of AC Circuits |
 68%
From NCERT
AIPMT - 2011
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The r.m.s. value of the potential difference V shown in the figure is:

1. V0/3

2. V0

3. V0/2

4. V0/2

Subtopic:  RMS & Average Values |
 73%
From NCERT
AIPMT - 2011
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A coil has a resistance of \(30~ \mathrm{ohm}\) and inductive reactance of \(20 ~\mathrm{ohm}\) at a \(50~\mathrm{ Hz}\) frequency. If an \(\mathrm{ac}\) source of \(200 ~\mathrm{volts,}\) \(100~\mathrm{ Hz}\) is connected across the coil, the current in the coil will be:

1. \(2.0~\mathrm{ A}\) 2. \(4.0~\mathrm{ A}\)
3. \(8.0~\mathrm{ A}\) 4. \(20/\sqrt{13}~\mathrm{A}\)
Subtopic:  Different Types of AC Circuits |
 59%
From NCERT
AIPMT - 2011
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