Magnetic Properties of Matter — JEE Main PYQs

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Consider a ferromagnetic material :
Assertion (A) : The individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact with one another in such a …

A short bar magnet placed with its axis at $30^{\circ }$ with an external field of 800 Gauss, experiences a torque of 0.016 N.m. The work done in moving it from most stable to most unstable position is $\alpha \times 10^{-3}\mathrm{J}$. The value of $\alpha$ is ______.

A solenoid has a core made of material with relative permeability 400. The magnetic field produced in the interior of solenoid is 1.0 T. The magnetic intensity is SI units is $\alpha \times 10^5$. The value of $\alpha$ is ______. (Free space permeability …

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason(R).
Assertion (A) : Magnetic monopoles do not exist.
Reason (R) : Magnetic field lines are continuous and form closed loops.
In the light of the above statements, choose the most …

The percentage increase in magnetic field (B) when space within a current carrying solenoid is filled with magnesium (magnetic susceptibility ${\chi }_{mg}=1.2\times 10^{-5}$) is:

Match List-I with List-II:
List-I: (A) Magnetic induction (B) Magnetic intensity (C) Magnetic flux (D) Magnetic moment
List-II: (I) Ampere meter² (II) Weber (III) Gauss (IV) Ampere/meter
Choose the correct answer from the options given below:

Match List-I with List-II :

The magnetic moment of a bar magnet is $0.5{\mathrm{Am}}^2$. It is suspended in a uniform magnetic field of $8\times 10^{-2}\mathrm{T}$. The work done in rotating it from its most stable to most unstable position is :

Paramagnetic substances:
A. align themselves along the directions of external magnetic field.
B. attract strongly towards external magnetic field.
C. has susceptibility little more than zero.
D. move from a region of strong magnetic field to weak magnetic field.

Choose the most …

The coercivity of a magnet is $5\times 10^3\mathrm{A}/\mathrm{m}$. The amount of current required to be passed in a solenoid of length 30 cm and the number of turns 150, so that the magnet gets demagnetised when inside the solenoid is ______ A.

A straight magnetic strip has a magnetic moment of $44{\mathrm{Am}}^2$. If the strip is bent in a semicircular shape, its magnetic moment will be ____ ${\mathrm{Am}}^2$.
(Given $\pi =\frac{22}{7}$ )

Given below are two statements; one is labelled as Assertion A and the other is labelled as Reason R

Assertion A: Electromagnets are made of soft iron.

Reason R: Soft iron has high permeability and low retentivity.

In the light of above, statements, choose the most appropriate …

Given below are two statements:

Statement I: For diamagnetic substance $-1\le \chi <0$, where $\chi$ is the magneticsusceptibility.

Statement II: Diamagnetic substances when placed in an external magnetic field, tend to move from stronger to weaker part of the field.

In t …

The current required to be passed through a solenoid of 15 cm length and 60 turns in order to demagnetise a bar magnet of magnetic intensity $2.4\times 10^3{\mathrm{Am}}^{-1}$ is ____ A.

The free space inside a current carrying toroid is filled with a material of susceptibility $2\times 10^{-2}$. The percentage increase in the value of magnetic field inside the toroid will be

Given below are two statements:

Statement I: The diamagnetic property depends on temperature.
Statement II: The induced magnetic dipole moment in a diamagnetic sample is always opposite to the magnetizing field.
In the light of given statement, choose the correct answer from the …

A bar magnet with a magnetic moment $5.0{\mathrm{Am}}^2$ is placed in parallel position relative to a magnetic field of 0.4 T. The amount of required work done in turning the magnet form parallel to antiparallel position relative to the field direction is ______.

A rod with circular cross-section area $2$ cm${}^2$ and length 40 cm is wound uniformly with 400 turns of an insulated wire. If a current of 0.4 A flows in the wire windings, the total magnetic flux produced inside windings is $4\pi \times 10^{-6}$ Wb. The relative permeability of …

The vertical component of the earth's magnetic field is $6\times 10^{-5}\mathrm{T}$ at any place where the angle of dip is $37^{\circ }$. The earth's resultant magnetic field at that place will be (Given $\tan 37^{\circ }=\frac{3}{4}$)

Two bar magnets oscillate in a horizontal plane in earth's magnetic field with time periods of 3 s and 4 s respectively. If their moments of inertia are in the ratio of $3:2$ then the ratio of their magnetic moments will be :

A magnet hung at $45^{\circ }$ with magnetic meridian makes an angle of $60^{\circ }$ with the horizontal. The actual value of the angle of dip is

A compass needle of oscillation magnetometer oscillates 20 times per minute at a place P of dip $30^{\circ }$. The number of oscillations per minute become 10 at another place Q of $60^{\circ }$ dip. The ratio of the total magnetic field at the two places …

The space inside a straight current carrying solenoid is filled with a magnetic material having magnetic susceptibility equal to $1.2\times 10^{-5}$. What is fractional increase in the magnetic field inside solenoid with respect to air as medium inside the solenoid?

A bar magnet having a magnetic moment of $2.0\times 10^5{\mathrm{JT}}^{-1}$, is placed along the direction of uniform magnetic field of magnitude $B=14\times 10^{-5}T$. The work done in rotating the magnet slowly through $60^{\circ }$ from the direction of field is :

At a certain place the angle of dip is $30^{\circ }$ and the horizontal component of earth's magnetic field is 0.5 G . The earth's total magnetic field (in G ), at that certain place, is :

The susceptibility of a paramagnetic material is 99. The permeability of the material in $\mathrm{Wb}/\mathrm{A}-\mathrm{m}$ is :
[Permeability of free space ${\mu }_0=4\pi \times 10^{-7}\mathrm{Wb}/\mathrm{A}-\mathrm{m}$ ]

The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has :

Given below are two statements:

Statement-I: Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature.
Statement - II: Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic …

A soft ferromagnetic material is placed in an external magnetic field. The magnetic domains:

At an angle of $30^{\circ }$ to the magnetic meridian, the apparent dip is $45^{\circ }$. Find the true dip:

The magnetic susceptibility of a material of a rod is 499 . Permeability in vacuum is $4\pi \times 10^{-7}\mathrm{H}/\mathrm{m}$. Absolute permeability of the material of the rod is:

Statement I : The ferromagnetic property depends on temperature. At high temperature, ferromagnet becomes paramagnet.

Statement II : At high temperature, the domain wall area of a ferromagnetic substance increases.
In the light of the above statements, choose the most appropriat …

Choose the correct option :

A long solenoid with $1000\mathrm{turns}/\mathrm{m}$ has a core material with relative permeability 500 and volume $10^3{\mathrm{cm}}^3$. If the core material is replaced by another material having relative permeability of 750 with same volume maintaining same current of 0 …

In a uniform magnetic field, the magnetic needle has a magnetic moment $9.85\times 10^{-2}\mathrm{A}/{\mathrm{m}}^2$ and moment of inertia $5\times 10^{-6}{\mathrm{kg}\mathrm{m}}^2$. If it performs 10 complete oscillations in 5 seconds then the magnitude of the magnetic field is ______ …

The value of aluminium susceptibility is $2.2\times 10^{-5}$. The percentage increase in the magnetic field if space within a current carrying toroid is filled with Aluminium is $\frac{\mathrm{x}}{10^4}$. Then the value of x is ____.

Following plots show Magnetization (M) vs Magnetising field (H) and Magnetic susceptibility (χ) vs temperature (T) graph:

Which of the following combination will be represented by a diamagnetic material?

A bar magnet of length 14 cm is placed in the magnetic meridian with its north pole pointing towards the geographic north pole. A neutral point is obtained at a distance of 18 cm from the centre of the magnet. If ${\mathrm{B}}_{\mathrm{H}}=0.4\mathrm{G}$, the magnetic moment of …

Which of the following statements are correct ?
(A) Electric monopoles do not exist whereas magnetic monopoles exist .
(B) Magnetic field lines due to a solenoid at its ends and outside can not be completely straight and confined
(C) Magnetic field lines are completely confined w …

The figure gives experimentally measured B vs H variation in a ferromagnetic material. The retentivity, coercivity and saturation, respectively, of the material are

An iron rod of volume $10^{-3}{\mathrm{m}}^3$ and relative permeability 1000 is placed as core in a solenoid with $10\mathrm{turns}/\mathrm{cm}$. If a current of 0.5 A is passed through the solenoid, then the magnetic moment of the rod will be:

A perfectly diamagnetic sphere has a small spherical cavity at its centre, which is filled with a paramagnetic substance. The whole system is placed in a uniform magnetic field $\vec{B}$. Then the field inside the paramagnetic substance is:

A small bar magnet placed with its axis at $30^{\circ }$ with an external field of 0.06 T experiences a torque of 0.018 Nm . The minimum work required to rotate it from its stable to unstable equilibrium position is:

A paramagnetic sample shows a net magnetisation of $6\text{ A/m}$ when it is placed in an external magnetic field of 0.4 T at a temperature of 4 K. When the sample is placed in an external magnetic field of 0.3 T at a temperature of 24 K, then the magnetisation will be:

A paramagnetic substance in the form of a cube with sides 1 cm has a magnetic dipole moment of $20\times 10^{-6}\mathrm{J}/\mathrm{T}$ when a magnetic intensity of $60\times 10^3\mathrm{A}/\mathrm{m}$ is applied. Its magnetic susceptibility is:

A magnetic compass needle oscillates 30 times per minute at a place where the dip is $45^{\circ }$, and 40 times per minute where the dip is $30^{\circ }$. If ${\mathrm{B}}_1$ and ${\mathrm{B}}_2$ are respectively the total magnetic field due to the earth at the two places, then th …

A paramagnetic material has $10^{28}$ atoms $/{\mathrm{m}}^3$. Its magnetic susceptibility at temperature 350 K is $2.8\times 10^{-4}$. Its susceptibility at 300 K is :

A bar magnet is demagnetized by inserting it inside a solenoid of length $0.2\mathrm{m},100$ turns, and carrying a current of 5.2 A . The coercivity of the bar magnet is

Hysteresis loops for two magnetic materials A and B are given below :

These materials are used to make magnets for electric generators, transformer core and electromagnet core. Then it is proper to use :

The coercivity of a small magnet where the ferromagnet gets demagnetized is $3\times 10^3{\mathrm{Am}}^{-1}$. The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is: