A sheet is placed on a horizontal surface in front of a strong magnetic pole. A force is needed to:
\(\mathrm A.\) hold the sheet there if it is magnetic.
\(\mathrm B.\) hold the sheet there if it is non-magnetic.
\(\mathrm C.\) move the sheet away from the pole with uniform velocity if it is conducting.
\(\mathrm D.\) move the sheet away from the pole with uniform velocity if it is both, non-conducting and non-polar.
Choose the correct statement\((\mathrm s )\) from the options given below:
1. \(\mathrm A\) and \(\mathrm C\) only
2. \(\mathrm A\), \(\mathrm C\) and \(\mathrm D\) only
3. \(\mathrm C\) only
4. \(\mathrm B\) and \(\mathrm D\) only
Subtopic:  Faraday's Law & Lenz Law |
From NCERT
NEET - 2024
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An ideal inductor-resistor-battery circuit is switched on at \(t=0~\text{s}\). At time \(t\), the current is \(i=i_0\left(1-e^{\left(-\frac{t}{\tau}\right)}\right)\text{A}\), where \(i_0\) is the steady-state value. The time at which the current becomes \(0.5i_0\) is: [Given \(\text{ln}(2)= 0.693\)]
1. \(6.93 \times 10^3 ~\text{s}\)
2. \(6.93~\text{ms}\)
3. \(69.3~\text{s}\)
4. \(6.93~\text{s}\)
Subtopic:  LR circuit |
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From NCERT
NEET - 2024
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A conducting circular loop of face area \(2.5 \times 10^{-3}~\text{m}^2\) is placed perpendicular to a magnetic field which varies as \(B=0.5\sin(100 \pi t)~\text{T}\). The magnitude of induced emf at time \(t= 0~\text{s}\) is: 
1. \(0.125 \pi~ \text{mV}\) 2. \(125 \pi ~\text{mV}\)
3. \(125 \pi~\text{V}\) 4. \(12.5 \pi~\text{mV}\)
Subtopic:  Faraday's Law & Lenz Law |
 64%
From NCERT
NEET - 2024
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A rod of length \(L\) rotates with a small uniform angular velocity \(\omega\) about its perpendicular bisector. A uniform magnetic field \(\mathrm B\) exists parallel to the axis of rotation. The potential difference between the centre of the rod and an end is:
1. \(\large\frac{B\omega L^2}{8}\)
2. \(\large\frac{B\omega L^2}{2}\)
3. \(\large\frac{B\omega L^2}{4}\)
4. zero
Subtopic:  Motional emf |
From NCERT
NEET - 2024
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Let us consider two solenoids \(A\) and \(B,\) made from the same magnetic material of relative permeability \(\mu_{r}\) and equal area of cross-section. Length of \(A\) is twice that of \(B\) and the number of turns per unit length in \(A\) is half that of \(B.\) The ratio of self inductances of the two solenoids, \(L_A:L_B\) is:
1. \(1:2\)
2. \(2:1\)
3. \(8:1\)
4. \(1:8\)
Subtopic:  Self - Inductance |
 60%
From NCERT
NEET - 2024
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The magnetic energy stored in an inductor of inductance \(4~\mu\text{H}\) carrying a current of \(2~\text{A}\) is:
1. \(8~\mu \text{J}\)
2. \(4~\mu \text{J}\)
3. \(4~\text{mJ}\)
4. \(8~\text{mJ}\)
Subtopic:  Self - Inductance |
 73%
From NCERT
NEET - 2023
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An emf is generated by an ac generator having \(100\) turn coil, of loop area \(1\) m2. The coil rotates at a speed of one revolution per second and placed in a uniform magnetic field of \(0.05\) T perpendicular to the axis of rotation of the coil. The maximum value of emf is:
1. \(3.14\) V
2. \(31.4\) V
3. \(62.8\) V
4. \(6.28\) V
Subtopic:  Motional emf |
 72%
From NCERT
NEET - 2023
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A square loop of side \(1~\text m\) and resistance \(1~\Omega\) is placed in a magnetic field of \(0.5~\text T.\) If the plane of the loop is perpendicular to the direction of the magnetic field, the magnetic flux through the loop is:
1. \(0\) 2. \(2\) weber
3. \(0.5\) weber 4. \(1\) weber
Subtopic:  Magnetic Flux |
 67%
From NCERT
NEET - 2022
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A big circular coil with \(1000\) turns and an average radius of \(10~\text{m}\) is rotating about its horizontal diameter at a rate of \(2~\text{rad s}^{-1}.\) The vertical component of the Earth's magnetic field at that location is \(2\times 10^{-5}~\text{T},\) and the electrical resistance of the coil is \(12.56~\Omega,\) 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 |
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From NCERT
NEET - 2022
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The current in an inductor of self-inductance \(4~\text{H}\) changes from \(4~ \text{A}\) to \(2~\text{A}\) in \(1~ \text s\). The emf induced in the coil is:
1. \(-2~\text{V}\)
2. \(2~\text{V}\)
3. \(-4~\text{V}\)
4. \(8~\text{V}\)

Subtopic:  Self - Inductance |
 83%
From NCERT
NEET - 2022
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