Magnetism and Matter

The magnetic moment of an iron bar is \(M\). It is now bent in such a way that it forms an arc section of a circle subtending an angle of \(60^{\circ}\) at the centre. The magnetic moment of this arc section is

The magnetic moment and moment of inertia of a magnetic needle as shown are, respectively, \(1.0 \times 10^{-2} \mathrm{~A} \mathrm{~m}^2\) and \(\frac{10^{-6}}{\pi^2} \mathrm{~kg} \mathrm{~m}^2\). If it completes 10 oscillations in $$10 \m...

The incorrect relation for a diamagnetic material (all the symbols carry their usual meaning and \(\varepsilon\) is a small positive number) is

The magnetic potential energy, when a magnetic bar of magnetic moment \(\vec{m}\) is placed perpendicular to the magnetic field \(\vec{B}\) is

In the above diagram, a strong bar magnet is moving towards solenoid-2 from solenoid-1. The direction of induced current in solenoid-1 and that in solenoid-2, respectively, are through the directions:

An iron bar of length \(L\) has 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 :

In a uniform magnetic field of \(0.049 \mathrm{~T}\), a magnetic needle performs 20 complete oscillations in 5 seconds as shown. The moment of inertia of the needle is \(9.8 \times 10^{-6} \mathrm{~kg} \mathrm{~m}^2\). If the magnitude of m...

A sheet is placed on a horizontal surface in front of a strong magnetic pole. A force is needed to:
A. hold the sheet there if it is magnetic.
B. hold the sheet there if it is non-magnetic.
C. move the sheet away from the pole with uniform ...

Match List I with List II

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The variation of susceptibility \((\chi)\) with absolute temperature ( \(\mathrm{T}\) ) for a paramagnetic material is represented as :

A big circular coil of 1000 turns and average radius 10 m is rotating about its horizontal diameter at 2 rad s\(-\)1. If the vertical component of earth's magnetic field at that place is 2 \(\times\) 10\(-\)5 T and electrical resistance of ...

A uniform conducting wire of length 12a and resistance 'R' is wound up as a current carrying coil in the shape of ,(i) an equilateral tringle of side 'a'(ii) A square of side 'a'The magnetic dipole moments of the coil in each case respectiv...

In the product\(\overrightarrow F = q\left( {\overrightarrow v \times \overrightarrow B } \right)\)\(= q\overrightarrow v \times \left( {B\widehat i + B\widehat j + {B_0}\widehat k} \right)\)For q = 1 and $$\overrightarrow v = 2\wideha...

An iron rod of susceptibility 599 is subjected to a magnetizing field of 1200 A m-1. The permeability of the material of the rod is :\(\left( {{\mu _0} = 4\pi \times {{10}^{ - 7}}Tm{A^{ - 1}}} \right)\)

At a point A on the earth’s surface the angle of dip, \(\delta\) = + 25o. At a point B on the earth's surface the angle of dip, \(\delta\) = – 25o. We can interpret that :

A thin diamagnetic rod is placed vertically
between the poles of an electromagnet. When
the current in the electromagnet is switched
on, then the diamagnetic rod is pushed up, out
of the horizontal magnetic field. Hence the rod
gains gravit...

A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 \(\mu\)A and subjected to a magnetic field of strength 0.85 T. Work done for rotating the coil by 180o against the torque is

If \(\theta\)1 and \(\theta\)2 be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip \(\theta\) is given by

A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by 60o is W. Now the torque required to keep the magnet in this new position is

The magnetic susceptibility is negative for

A rectangular coil of length 0.12 m and width 0.1 m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0.2 weber/m2. The coil carries a current of 2 A. If the plane of the coil is inclined at an angle of...

Following figures show the arrangement of bar magnets in different configurations. Each magnet has magnetic dipole moment \(\overrightarrow m .\) Which configuration has highest net magnetic dipole moment ?

A bar magnet of 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

A current loop in a magnetic field

A bar magnet of length \('l'\) and magnetic dipole moment 'M' is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be

A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It

A magnetic needle suspended parallel to a magnetic field requires \(\sqrt 3 J\) of work to turn it through 60o. The torque needed to maintain the needle in this position will be

There are four light-weight-rod samples A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted
(i)  A is feebly repelled
(ii)  B is feebly attracted
(iii)  C is ...

A short bar magnet of magnetic moment 0.4 J T\(-\)1 is placed in a uniform magnetic field of 0.16 T. The magnet is in stable equilibrium when the potential energy is

A vibration magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 sec in earth's horizontal magnetic field of 24 microtesla. When a horizontal field of 18 microtesla is pr...

Electromagnets are made of soft iron because soft iron has

The magnetic moment of a diamagnetic action is

Two identical bar magnets are fixed with their centers at a distance d apart. A stationary charge Q is placed at P in between the gap of the two magnets at a distance D from the centre O as shown in the figure

The force on the charge Q is...

A bar magnet having a magnetic moment of 2 \(\times\) 104 J T\(-\)1 is free to rotate in a horizontal plane. A horizontal magnetic field B = 6 \(\times\) 10\(-\)4 T exists in the space. The work done in taking the magnet slowly from a d...

If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is

Curie temperature above which

A charged particle (charge q) is moving in a circle of radius R with uniform speed v. The associated magnetic moment \(\mu\) is given by

Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show

Curie temperature above which

A coil in the shape of an equilateral triangle of side \(l\) is suspended between the pole pieces of a permanent magnet such that \(\overrightarrow B\) is in plane of the coil. If due to a current i in the triangle a torque \(\tau\) acts ...

If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by \(\mu\)d, \(\mu\)p and \(\mu\)f respectively, then

A bar magnet is oscillating in the Earth's magnetic field with a period T. What happens to its period and motion if its mass is quadrupled?

According to Curie's law, the magnetic susceptibility of a substance at an absolute temperature \(T\) is proportional to

A diamagnetic material in a magnetic field moves

Two bar magnets having same geometry with magnetic moments M and 2M, are firstly placed in such a way that their similar poles are same side then its time period of oscillation is T1. Now the polarity of one of the magnet is reversed then t...

Tangent galvanometer is used to measure

Among which the magnetic susceptibility does not depened on the temperature ?