The length of a magnetized iron bar is \(L\) and its magnetic moment is \(M.\) When this bar is bent to form a semicircle its magnetic moment is:
1. \(M\) 2. \(\dfrac{M\pi}{2}\)
3. \( \dfrac{M}{2\pi}\) 4. \(\dfrac{2M}{\pi}\)
Subtopic:  Bar Magnet |
 75%
Level 2: 60%+
NEET - 2024
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An iron bar of length \( L\) has a magnetic moment \(M.\) It is bent at the middle of its length such that the two arms make an angle \(60^\circ\) with each other. The magnetic moment of this new magnet is:
1. \(\dfrac{M}{2}\) 2. \({2 M}\)
3. \(\dfrac{{M}}{\sqrt{3}}\) 4. \(M\)
Subtopic:  Bar Magnet |
 53%
Level 3: 35%-60%
NEET - 2024
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In a uniform magnetic field of \(0.049~\text T\), a magnetic needle performs \(20\) complete oscillations in \(5\) seconds as shown. The moment of inertia of the needle is \(9.8 × 10^{-6} ~\text{kg m}^2\). If the magnitude of magnetic moment of the needle is \(x \times 10^{-5 }~\text {Am}^2;\) then the value of '\(x\)' is:
1. \(128\pi^2\) 2. \(50\pi^2\)
3. \(1280\pi^2\) 4. \(5\pi^2\)
Subtopic:  Bar Magnet |
 52%
Level 3: 35%-60%
NEET - 2024
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A bar magnet of the magnetic moment \(M\) is placed at right angles to a magnetic induction \(B.\) If a force \(F\) is experienced by each pole of the magnet, the length of the magnet will be:
1. \(\dfrac{MB}{F}\) 2. \(\dfrac{BF}{M}\)
3. \(\dfrac{MF}{B}\) 4. \(\dfrac{F}{MB}\)
Subtopic:  Bar Magnet |
 76%
Level 2: 60%+
NEET - 2013
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A bar magnet of length \(l\) and magnetic dipole moment \(M\) is bent in the form of an arc as shown in the figure. The new magnetic dipole moment will be:

1. \(\dfrac{3M}{\pi}\) 2. \(\dfrac{2M}{l\pi}\)
3. \(\dfrac{M}{ 2}\) 4. \(M\)
Subtopic:  Bar Magnet |
 81%
Level 1: 80%+
AIPMT - 2013
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The magnetic potential energy when a magnetic bar with a magnetic moment \(\vec{M}\) is placed perpendicular to the magnetic field \(\vec{B}\) is:
1. \(\dfrac{-mB}{2}\) 2. zero
3. \(-mB\) 4. \(mB\)
Subtopic:  Analogy between Electrostatics & Magnetostatics |
 75%
Level 2: 60%+
NEET - 2024
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The net magnetic flux through any closed surface is:
1. negative 2. zero
3. positive 4. infinity
Subtopic:  Analogy between Electrostatics & Magnetostatics |
 86%
Level 1: 80%+
NEET - 2023
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Select the correct option based on the statements:
Statement I:  The magnetic field of a circular loop at very far away point on the axial line varies with distance as like that of a magnetic dipole.
Statement II: The magnetic field due to magnetic dipole varies inversely with the square of the distance from the centre on the axial line.
 
1. Statement I is correct and Statement II is incorrect.
2. Statement I is incorrect and Statement II is correct.
3. Both Statement I and Statement II are correct.
4. Both Statement I and Statement II are incorrect.
Subtopic:  Analogy between Electrostatics & Magnetostatics |
 57%
Level 3: 35%-60%
NEET - 2022
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Given below are two statements:
Assertion (A): Gauss's law for magnetism states that the net magnetic flux through any closed surface is zero.
Reason (R): The magnetic monopoles do not exist. North and South poles occur in pairs, allowing vanishing net magnetic flux through the surface.
 
1. (A) is True but (R) is False.
2. (A) is False but (R) is True.
3. Both (A) and (R) are True and (R) is the correct explanation of (A).
4. Both (A) and (R) are True but (R) is not the correct explanation of (A).
Subtopic:  Analogy between Electrostatics & Magnetostatics |
 76%
Level 2: 60%+
NEET - 2022
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A magnetic needle suspended parallel to a magnetic field requires \(\sqrt{3}~\text{J}\) of work to turn it through \(60^\circ\). The torque needed to maintain the needle in this position will be:
1. \(3\) N-m
2. \(\sqrt{3} \) N-m
3. \(\frac32\) N-m
4. \(2\sqrt{3}\) N-m

Subtopic:  Analogy between Electrostatics & Magnetostatics |
 72%
Level 2: 60%+
AIPMT - 2012
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