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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A circular loop of radius \(\mathrm{R}\), enters a region of uniform magnetic field \(\mathrm{B}\) as shown in the diagram. The field \((\mathrm{B})\) is perpendicular to the plane of the loop while the velocity of the loop,\(\mathrm{v}\), is along its plane. The induced EMF:
                        
1. increases continuously. 
2. decreases continuously.
3. first increases and then decreases.
4. remains constant throughout.
Subtopic:  Faraday's Law & Lenz Law |
 69%
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A big circular coil of \(1000\) turns and average radius \(10~\text{m}\)  is rotating about its horizontal diameter at \(2~\text{rad s}^{-1}\). If the vertical component of earth's magnetic field at that place is \(2\times 10^{-5}~\text{T}\) and electrical resistance of the coil is \(12.56~\Omega,\) then the maximum induced current in the coil will be:
1. \(2~\text{A}\)
2. \(0.25~\text{A}\)
3. \(1.5~\text{A}\)
4. \(1~\text{A}\)
Subtopic:  Faraday's Law & Lenz Law |
 51%
From NCERT
NEET - 2022
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The magnetic field, through a closed loop of conducting wire covering an area of \(100\) cm2, is \(5\times10^{-2}\) T and it is uniform and normal to the area. If the field is switched off in a time of \(10\) ms, the average emf induced is:
1. \(5\) V
2. \(0.5\) V
3. \(0.05\) V
4. \(5\times10^{-4}\) V
Subtopic:  Faraday's Law & Lenz Law |
 78%
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The figure shows planar loops of different shapes moving out of or into a region of a magnetic field which is directed normally to the plane of the loop away from the reader. Then:

            

1. for the rectangular loop abcd, the induced current is clockwise.
2. for the triangular loop abc, the induced current is clockwise.
3. for the irregularly shaped loop abcd, the induced current is anti-clockwise.
4. none of these.

Subtopic:  Faraday's Law & Lenz Law |
 66%
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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 wire loop is rotated in a magnetic field. The frequency of change of direction of the induced emf is:
1. twice per revolution.
2. four times per revolution.
3. six times per revolution.
4. once per revolution.
 
Subtopic:  Faraday's Law & Lenz Law |
 74%
From NCERT
AIPMT - 2013
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A rectangular loop of conducting wire is bent symmetrically so that its two plane halves are inclined at right angles with respect to each other (i.e. \(\angle \text { PQR }=\angle S T U=90^{\circ}\)). Every segment has a length 'a' (PQ = QR = RS = ... = UP = a). A uniform time-dependent magnetic field B(t) acts on the loop, making an angle '\(\alpha\)' with the lower half of the loop and '\(90^o - \alpha \)' with the upper half. The EMF induced in the loop is proportional to:
                 
\(1.~ (\cos \alpha+\sin \alpha) \frac{d B}{d t}\\ 2.~ (\cos \alpha-\sin \alpha) \frac{d B}{d t}\\ 3.~ (\tan \alpha+\cot \alpha) \frac{d B}{d t}\\ 4.~ (\tan \alpha-\cot \alpha) \frac{dB}{d t}\)
Subtopic:  Faraday's Law & Lenz Law |
From NCERT
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