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Q. No.The variation of EMF with time for four types of generators is shown in the figures. Which amongst them can be called AC voltage?
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| (a) | (b) |
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| (c) | (d) |
Choose the correct option from the given ones:
| 1. | (a) and (d) |
| 2. | (a), (b), (c), and (d) |
| 3. | (a) and (b) |
| 4. | only (a) |
Subtopic: AC vs DC |
79%
Level 2: 60%+
NEET - 2019
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In an AC circuit \(I=100~\sin(200\pi t).\) The time required for the current to reach its peak value will be:
| 1. | \(\frac{1}{100}~\text{sec}\) | 2. | \(\frac{1}{200}~\text{sec}\) |
| 3. | \(\frac{1}{300}~\text{sec}\) | 4. | \(\frac{1}{400}~\text{sec}\) |
Subtopic: RMS & Average Values |
67%
Level 2: 60%+
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A \(100~\Omega\) resistor is connected to a \(220~\text{V}\), \(50~\text{Hz}\) \(\text{AC}\) supply. The net power consumed over a full cycle is:
| 1. | \(484~\text{W}\) | 2. | \(848~\text{W}\) |
| 3. | \(400~\text{W}\) | 4. | \(786~\text{W}\) |
Subtopic: Power factor |
87%
Level 1: 80%+
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The peak value of an alternating emf; \(E = E_{0}\sin\omega t\) is \(10~\text V\) and its frequency is \(50~\text{Hz}.\) At a time \(t=\dfrac{1}{600}~\text{s},\) the instantaneous value of the emf will be:
1. \(1~\text V\)
2. \(5\sqrt 3~\text V\)
3. \(5~\text V\)
4. \(10~\text V\)
Subtopic: RMS & Average Values |
79%
Level 2: 60%+
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The output current versus time curve of a rectifier is shown in the figure. The average value of the output current in this case will be:
1. \(0\)
2. \(\dfrac{I_0}{2}\)
3. \(\dfrac{2I_0 }{ \pi}\)
4. \(I_0\)
Subtopic: RMS & Average Values |
67%
Level 2: 60%+
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How much power is dissipated in an \(LCR\) series circuit connected to an \(\text{AC}\) source of emf \( E\)?
| 1. | \(\frac{\varepsilon^{2} R}{\left[R^{2}+\left(L \omega-\frac{1}{C \omega}\right)^{2}\right]}\) | 2. | \(\frac{\varepsilon^{2} \sqrt{R^{2}+\left(L \omega-\frac{1}{C \omega}\right)^{2}}}{R}\) |
| 3. | \(\frac{\varepsilon^{2}\left[R^{2}+\left(L \omega-\frac{1}{C \omega}\right)^{2}\right]}{R}\) | 4. | \(\frac{\varepsilon^{2}R}{\sqrt{R^{2}+\left(L \omega-\frac{1}{C \omega}\right)^{2}}}\) |
Subtopic: Power factor |
70%
Level 2: 60%+
AIPMT - 2009
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An alternating current is given as \(i = i_1\cos\omega t- i_2 \sin \omega t.\) The value of rms current is given by:
1. \( \frac{1}{\sqrt{2}}\left(i_1+i_2\right) \)
2. \( \frac{1}{\sqrt{2}}\left(i_i+i_2\right)^2 \)
3. \( \frac{1}{\sqrt{2}}\left(i_1^2+i_2^2\right)^{1 / 2} \)
4. \( \frac{1}{2}\left(i_1^2+i_2^2\right)^{1 / 2}\)
1. \( \frac{1}{\sqrt{2}}\left(i_1+i_2\right) \)
2. \( \frac{1}{\sqrt{2}}\left(i_i+i_2\right)^2 \)
3. \( \frac{1}{\sqrt{2}}\left(i_1^2+i_2^2\right)^{1 / 2} \)
4. \( \frac{1}{2}\left(i_1^2+i_2^2\right)^{1 / 2}\)
Subtopic: RMS & Average Values |
81%
Level 1: 80%+
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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 resistance of \(20~ \Omega\) is connected to a source of an alternating potential, \(V=220\sin(100 \pi t).\) The time taken by the current to change from its peak value to its rms value will be:
| 1. | \( 0.2~\text{sec}\) | 2. | \( 0.25~\text{sec}\) |
| 3. | \(25 \times10^{-3}~\text{sec}\) | 4. | \(2.5 \times10^{-3}~\text{sec}\) |
Subtopic: RMS & Average Values |
68%
Level 2: 60%+
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A generator produces a voltage that is given by \(V = 240\sin(120t)\), where \(t\) is in seconds. The frequency and rms voltage are:
| 1. | \(60\) Hz and \(240\) V |
| 2. | \(19\) Hz and \(120\) V |
| 3. | \(19\) Hz and \(170\) V |
| 4. | \(754\) Hz and \(70\) V |
Subtopic: RMS & Average Values |
84%
Level 1: 80%+
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