The current \(i\) in a coil varies with time as shown in the figure. The variation of induced emf with time would be:
    

1. 2.
3. 4.

Subtopic:  Faraday's Law & Lenz Law |
 69%
From NCERT
AIPMT - 2011
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A conducting circular loop is placed in a uniform magnetic field, \(B=0.025~\text{T}\) with its plane perpendicular to the loop. The radius of the loop is made to shrink at a constant rate of \(1~\text{mm s}^{-1}\).  The induced emf, when the radius is \(2~\text{cm}\), is:
1. \(2\pi ~\mu\text{V}\)
2. \(\pi ~\mu\text{V}\)
3. \(\frac{\pi}{2}~\mu\text{V}\)
4. \(2 ~\mu \text{V}\)

Subtopic:  Faraday's Law & Lenz Law |
 75%
From NCERT
AIPMT - 2010
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A conducting circular loop is placed in a uniform magnetic field of 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at a rate of 2 mm/s. The induced e.m.f. in the loop when the radius is 2 cm is:

1. \(3.2\pi ~\mu V\)

2. \(4.8\pi ~\mu V\)

3. \(0.8\pi ~\mu V\)

4. \(1.6\pi ~\mu V\)

Subtopic:  Faraday's Law & Lenz Law |
 69%
From NCERT
AIPMT - 2009
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A rectangular, a square, a circular, and an elliptical loop, all in the (x-y) plane, are moving out of a uniform magnetic field with a constant velocity, v=vi^. The magnetic field is directed along the negative z-axis direction. The induced emf, during the passage of these loops out of the field region, will not remain constant for:

1. the rectangular, circular, and elliptical loops.
2. the circular and the elliptical loops.
3. only the elliptical loop.
4. any of the four loops.

Subtopic:  Motional emf |
 71%
From NCERT
AIPMT - 2009
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A long solenoid has \(500\) turns. When a current of \(2\) A is passed through it, the resulting magnetic flux linked with each turn of the solenoid is \(4\times 10^{-3} \) Wb. The self-inductance of the solenoid is:
1. \(2.5\) H
2. \(2.0\) H
3. \(1.0\) H
4. \(4.0\) H

Subtopic:  Self - Inductance |
 78%
From NCERT
AIPMT - 2008
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A circular disc of radius \(0.2~\text{m}\) is placed in a uniform magnetic field of induction \(\frac{1}{\pi}~\text{Wb/m}^{2}\) in such a way that its axis makes an angle of \(60^{\circ}\) with \(\vec{B}.\) The magnetic flux linked with the disc is:
1. \(0.02~\text{Wb}\)
2. \(0.06~\text{Wb}\)
3. \(0.08~\text{Wb}\)
4. \(0.01~\text{Wb}\)
Subtopic:  Magnetic Flux |
 84%
From NCERT
AIPMT - 2008
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The primary and secondary coils of a transformer have \(50\) and \(1500\) turns respectively. If the magnetic flux \(\phi\) linked with the primary coil is given by \(\phi=\phi_0+4t,\) where \(\phi\) is in Weber, \(t\) is time in seconds, and \(\phi_0\)  is a constant, the output voltage across the secondary coil is:
1. \(90~\mathrm{V}\)
2. \(120~\mathrm{V}\)
3. \(220~\mathrm{V}\)
4. \(30~\mathrm{V}\)

Subtopic:  Magnetic Flux |
 80%
From NCERT
AIPMT - 2007
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Two coils of self-inductance 2 mH and 8 mH are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is:

1. 10 mH

2. 6 mH

3. 4 mH

4. 16 mH

Subtopic:  Mutual Inductance |
 73%
From NCERT
AIPMT - 2006
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The current (\(I\)) in the inductance is varying with time (\(t\)) according to the plot shown in the figure. 

          
Which one of the following is the correct variation of voltage with time in the coil?
1.   2.
3. 4.
Subtopic:  Self - Inductance |
 73%
From NCERT
AIPMT - 2012
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A coil of resistance \(400~\Omega\) is placed in a magnetic field. The magnetic flux \(\phi~\text{(Wb)}\) linked with the coil varies with time \(t~\text{(s)}\) as \(\phi=50t^{2}+4.\) The current in the coil at \(t=2~\text{s}\) is:
1. \(0.5~\text{A}\)
2. \(0.1~\text{A}\)
3. \(2~\text{A}\)
4. \(1~\text{A}\)

Subtopic:  Faraday's Law & Lenz Law |
 87%
From NCERT
AIPMT - 2012
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