Assertion (A) : All atoms have a net magnetic moment.
Reason (R) : A current loop does not always behave as a magnetic dipole.
CBSE CLASS 12 • PHYSICS • CHAPTER 05
Magnetism and Matter
30 distinct questions across 40 board paper set appearances (2022–2026).
Assertion (A): When a ferromagnetic substance is heated to high temperature it becomes paramagnetic in nature. Reason (R): The disappearance of magnetisation of a ferromagnet is abrupt and not gradual.
A bar magnet is initially at right angles to a uniform magnetic field. The magnet is rotated till the torque acting on it becomes one-half of its initial value. The angle through which the bar magnet is rotated is :
(A) $30^{\circ}$
(B) $45^{\circ}$
(C) $60^{\circ}$
(D) $75^{\circ}$
A vertically held bar magnet is dropped along the axis of a copper ring having a cut as shown in the diagram. The acceleration of the falling magnet is :
(A) zero
(B) less than $g$
(C) $g$
(D) greater than $g$
The magnetic susceptibility for a diamagnetic material is
(A) small and negative
(B) small and positive
(C) large and negative
(D) large and positive
Which of the following materials has positive and small value of magnetic susceptibility ?
(A) $\text{Cu}$
(B) $\text{Al}$
(C) $\text{Bi}$
(D) $\text{Ni}$
Which of the following substance has relative magnetic permeability $\mu_r \gg 1$?
(A) Aluminium
(B) Copper
(C) Lead
(D) Nickel
Which one of the following materials has magnetic susceptibility $\chi$ in the range $-1 \le \chi < 0$ ?
(A) Aluminium
(B) Copper chloride
(C) Copper
(D) Nickel
An electric current can be induced in a wire loop if -
(A) the wire loop is wound around a bar magnet.
(B) a bar magnet is placed in contact with the wire loop.
(C) a bar magnet is placed near the wire loop.
(D) a bar magnet is moved rapidly towards the wire loop.
A light copper ring is freely suspended by a light string. A bar magnet is held horizontally with its length along the axis of the ring. The magnet is moved towards the ring with its N pole facing the loop. What will happen to the ring and its position ? Explain.
Draw a diagram representing the behaviour of magnetic field lines for a
(A) diamagnetic &
(B) paramagnetic substance.
For VI-Candidates
Sate Gauss's law of magnetism? Hence find the magnetic flux linked with the sphere enclosing a current carrying solenoid?
Which one out of the following materials is \textbf{not} paramagnetic ?
(A) Aluminium
(B) Sodium Chloride
(C) Calcium
(D) Copper Chloride
The materials having negative magnetic susceptibility are :
(A) diamagnetic
(B) paramagnetic
(C) ferromagnetic
(D) non-magnetic
Which of the following substances has magnetic permeability less than that of free space ?
(A) Sodium
(B) Iron
(C) Aluminium
(D) Copper
The magnetic moment ($5\text{ J/T}$) of a bar magnet points along a uniform magnetic field $0\cdot 4\text{ T}$.
(a) Calculate (i) the potential energy of the bar magnet, and (ii) the work done in turning the magnet by $180^{\circ}$.
(b) In which case is the potential energy of the magnet minimum ?
A material is pushed out when placed in a uniform magnetic field. The material is
(A) non-magnetic
(B) diamagnetic
(C) paramagnetic
(D) ferromagnetic
The dimensions of permeability of a medium are :
(A) $[\text{MLT}^{-1}\text{A}^{-1}]$
(B) $[\text{MLT}^{-2}\text{A}^{-2}]$
(C) $[\text{ML}^{-2}\text{T}^{-2}\text{A}^{-1}]$
(D) $[\text{MLT}^{-2}\text{A}^{-1}]$
A bar magnet is thrown from a distance into a closed loop with its north pole towards the loop and passes through it. The induced current in the loop is :
(A) first clockwise and then anticlockwise
(B) first anticlockwise and then clockwise
(C) clockwise only
(D) anticlockwise only
Which of the following substances has relative magnetic permeability $\mu_r \gg 1$ ?
(A) Aluminium (B) Copper chloride
(C) Nickel (D) Sodium chloride
The relative magnetic permeability of a medium is 0.075. Its magnetic susceptibility will be : (A) 0.925 (B) -0.925 (C) 1.075 (D) -1.075
Differentiate between magnetisation and the susceptibility of a material. What can you say about the susceptibility of paramagnetic and diamagnetic materials ?
When a ferromagnetic substance is heated to a temperature above its Curie temperature, it will :
(A) behave like a diamagnetic material.
(B) behave like a paramagnetic material.
(C) permanently demagnetise.
(D) remain a ferromagnetic.
Which of the following is a diamagnetic substance ?
(A) Gadolinium
(B) Sodium
(C) Copper chloride
(D) Sodium chloride
Which of the following pairs is that of paramagnetic materials ?
(A) Copper and Aluminium
(B) Sodium and Calcium
(C) Lead and Iron
(D) Nickel and Cobalt
An iron needle is kept near a strong bar magnet. It will experience
(A) a force of attraction and no torque.
(B) a force of attraction and a torque.
(C) a torque and no force.
(D) neither a force nor a torque.
Which of the following material has its magnetic susceptibility $\chi$ in the range $0 < \chi < \epsilon$, where $\epsilon$ is positive and small?
(A) Aluminium
(B) Water
(C) Gadolinium
(D) Bismuth
The relative magnetic permeability of a substance X is slightly less than unity and that of substance Y is slightly more than unity, then
(a) X is paramagnetic and Y is ferromagnetic
(b) X is diamagnetic and Y is ferromagnetic
(c) X and Y both are paramagnetic
(d) X is diamagnetic and Y is paramagne...
A bar magnet is cut into two equal halves parallel to its magnetic axis. The physical quantity that remains unchanged is :
(a) pole strength
(b) magnitude of magnetisation
(c) moment of inertia
(d) magnetic moment
A bar magnet of pole strength (m) and magnetic moment (M) is cut perpendicular to its axis in two equal halves. The new pole strength (m') and magnetic moment (M') of each part are respectively :
(a) m and M
(b) m and $\frac{M}{2}$
(c) $\frac{m}{2}$ and 2M
(d) 2m and $\frac{M}{2}$
If the magnetizing field on a ferromagnetic material is increased, its permeability
(i) decreases
(ii) increases
(iii) remains unchanged
(iv) first decreases and then increases