In the circuit shown, the AC source has a voltage
\(V= 20\cos(\omega t)\) volts with \(\omega = 2000\) rad/s. The amplitude of the current will be nearest to:


1. \(2\) A
2. \(3.3\) A
3. \(\frac{2}{\sqrt{5}}\) A
4. \(\sqrt{5}\) A

Subtopic:  Different Types of AC Circuits |
 56%
Level 3: 35%-60%
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The AC source in the circuit shown in the figure produces a voltage \(V = 20\cos(2000t)\) volts. Neglecting source resistance, the voltmeter and ammeter readings will be (approximately):

1. \(4~\text{V}, 2.0~\text{A}\) 2. \(0~\text{V}, 2~\text{A}\)
3. \(5.6~\text{V}, 1.4~\text{A}\) 4. \(8~\text{V}, 2.0~\text{A}\)
Subtopic:  Different Types of AC Circuits |
 61%
Level 2: 60%+
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An AC ammeter is used to measure the current in a circuit. When a given direct current passes through the circuit, the AC ammeter reads \(6~\text A.\) When another alternating current passes through the circuit, the AC ammeter reads \(8~\text A.\) Then the reading of this ammeter if DC and AC flow through the circuit simultaneously is:
1. \(10 \sqrt{2}~\text A\) 
2. \(14~\text A\) 
3. \(10~\text A\) 
4. \(15~\text A\) 

Subtopic:  AC vs DC |
 67%
Level 2: 60%+
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If \(q\) is the capacitor's charge and \(i\) is the current at time \(t\), the voltage \(V\) will be:

1. \(L \frac{di}{dt}+{iR}-\frac{q}{C}=V\)
2. \(L \frac{di}{dt}-{iR}+\frac{q}{C}=V\)
3. \(L \frac{di}{dt}+{iR}+\frac{q}{C}=V\)
4. \(L\frac{di}{dt}-{iR}-\frac{q}{C}=V\)
Subtopic:  Different Types of AC Circuits |
 56%
Level 3: 35%-60%
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A direct current of \(5~ A\) is superimposed on an alternating current \(I=10sin ~\omega t\) flowing through a wire. The effective value of the resulting current will be:

1. \(15/2~A\) 2. \(5 \sqrt{3}~A\)
3. \(5 \sqrt{5}~A\) 4. \(15~A\)
Subtopic:  AC vs DC |
 62%
Level 2: 60%+
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An \(LCR\) series circuit with \(100~\Omega\) resistance is connected to an AC source of \(200~\text V\) and an angular frequency of \(300~\text{rad/s}.\) When only the capacitance is removed, the current lags behind the voltage by \(60^{\circ}.\) When only the inductance is removed, the current leads the voltage by \(60^{\circ}.\) Calculate the power dissipated in the \(LCR\) circuit.
1. \(200~\text W\) 
2. \(400~\text W\) 
3. \(300~\text W\) 
4. zero

Subtopic:  Power factor |
 67%
Level 2: 60%+
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An ideal resistance \(R,\) ideal inductance \(L,\) ideal capacitance \(C,\) and AC voltmeters \(V_1, V_2, V_3~\text{and}~V_4 \)are connected to an AC source as shown. At resonance:
    

1. reading in \(V_3\) = reading in \(V_1\)
2. reading in \(V_1\) = reading in \(V_2\)
3. reading in \(V_2\) = reading in \(V_4\)
4. reading in \(V_2\) = reading in \(V_3\)
Subtopic:  Different Types of AC Circuits |
 86%
Level 1: 80%+
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A transistor-oscillator using a resonant circuit with an inductance \(L\) (of negligible resistance) and a capacitance \(C\) has a frequency \(f\). If \(L\) is doubled and \(C\) is changed to \(4C\), the frequency will be:
1. \(\frac{f}{4}\)
2. \(8f\)
3. \(\frac{f}{2\sqrt{2}}\)
4. \(\frac{f}{2}\)

Subtopic:  Different Types of AC Circuits |
 87%
Level 1: 80%+
AIPMT - 2006
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In an \(LCR\) series AC circuit, the voltage across each of the components \(L, C\) and \(R\) is \(50\) V. The voltage across the \(LR\) combination will be:
1. \(50\) V 2. \(50 \sqrt{2} ~\text{V}\)
3. \(100\) V 4. \(0\) V
Subtopic:  Different Types of AC Circuits |
 72%
Level 2: 60%+
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In a heating arrangement, an alternating current having a peak value of \(28~\text{A}\) is used. To produce the same heat energy, if direct current is used to produce the same amount of heat, then its magnitude will be:
1. about \(14~\text{A}\)  2. about \(28~\text{A}\)
3. about \(20~\text{A}\) 4. cannot say
Subtopic:  AC vs DC |
 57%
Level 3: 35%-60%
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