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Solution
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Q.1 Correct
Q.1 In-correct
Q.1 Unattempt

Match List - I with List - II.

List - I List - II
(A) Magnetic induction (I) Ampere meter2
(B) Magnetic intensity (II) Weber
(C) Magnetic flux (III) Gauss
(D) Magnetic moment (IV) Ampere meter

Choose the correct answer from the options given below:



JEE Main 2025 (Online) 29th January Evening Shift

Match List - I with List - II.

List - I List - II
(A) Magnetic induction (I) Ampere meter2
(B) Magnetic intensity (II) Weber
(C) Magnetic flux (III) Gauss
(D) Magnetic moment (IV) Ampere meter

Choose the correct answer from the options given below:



JEE Main 2025 (Online) 29th January Evening Shift
Q.2 Correct
Q.2 In-correct
Q.2 Unattempt

The relationship between the magnetic susceptibility $(x)$ and the magnetic permeability $(\mu)$ is given by :

( $\mu_0$ is the permeability of free space and $\mu_T$ is relative permeability)



JEE Main 2025 (Online) 2nd April Morning Shift

The relationship between the magnetic susceptibility $(x)$ and the magnetic permeability $(\mu)$ is given by :

( $\mu_0$ is the permeability of free space and $\mu_T$ is relative permeability)



JEE Main 2025 (Online) 2nd April Morning Shift
Q.3 Correct
Q.3 In-correct
Q.3 Unattempt
A magnetic dipole experiences a torque of $80 \sqrt{3} \mathrm{~N} \mathrm{~m}$ when placed in uniform magnetic field in such a way that dipole moment makes angle of $60^{\circ}$ with magnetic field. The potential energy of the dipole is :

JEE Main 2025 (Online) 3rd April Evening Shift
A magnetic dipole experiences a torque of $80 \sqrt{3} \mathrm{~N} \mathrm{~m}$ when placed in uniform magnetic field in such a way that dipole moment makes angle of $60^{\circ}$ with magnetic field. The potential energy of the dipole is :

JEE Main 2025 (Online) 3rd April Evening Shift
Q.4 Correct
Q.4 In-correct
Q.4 Unattempt

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



JEE Main 2025 (Online) 7th April Morning Shift

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



JEE Main 2025 (Online) 7th April Morning Shift
Q.5 Correct
Q.5 In-correct
Q.5 Unattempt
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 appropriate answer from the options given below:



JEE Main 2025 (Online) 7th April Evening Shift
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 appropriate answer from the options given below:



JEE Main 2025 (Online) 7th April Evening Shift
Q.6 Correct
Q.6 In-correct
Q.6 Unattempt

The horizontal component of earth's magnetic field at a place is 3.5 × 10−5T. A very long straight conductor carrying current of √2A in the direction from South east to North West is placed. The force per unit length experienced by the conductor is ......... × 10−6N∕m.

[30-Jan-2024 Shift 1]

The horizontal component of earth's magnetic field at a place is 3.5 × 10−5T. A very long straight conductor carrying current of √2A in the direction from South east to North West is placed. The force per unit length experienced by the conductor is ......... × 10−6N∕m.

[30-Jan-2024 Shift 1]
Q.7 Correct
Q.7 In-correct
Q.7 Unattempt

A ceiling fan having 3 blades of length 80cm each is rotating with an angular velocity of 1200rpm. The magnetic field of earth in that region is 0.5G and angle of dip is 30∘. The emf induced across the blades is Nπ × 10−5V. The value of N is____

[30-Jan-2024 Shift 1]

A ceiling fan having 3 blades of length 80cm each is rotating with an angular velocity of 1200rpm. The magnetic field of earth in that region is 0.5G and angle of dip is 30∘. The emf induced across the blades is Nπ × 10−5V. The value of N is____

[30-Jan-2024 Shift 1]
Q.8 Correct
Q.8 In-correct
Q.8 Unattempt
Certain galvanometers have a fixed core made of non magnetic metallic material. The function of this metallic material is
[8-Apr-2023 shift 1]
Certain galvanometers have a fixed core made of non magnetic metallic material. The function of this metallic material is
[8-Apr-2023 shift 1]
Q.9 Correct
Q.9 In-correct
Q.9 Unattempt
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, chose the most appropriate answer from the options given below.
[8-Apr-2023 shift 2]
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, chose the most appropriate answer from the options given below.
[8-Apr-2023 shift 2]
Q.10 Correct
Q.10 In-correct
Q.10 Unattempt
The current required to be passed through a solenoid of 15‌cm length and 60 turns in order to demagnetize a bar magnet of magnetic intensity 2.4×103Am−1 is _______ A.
[10-Apr-2023 shift 1]
The current required to be passed through a solenoid of 15‌cm length and 60 turns in order to demagnetize a bar magnet of magnetic intensity 2.4×103Am−1 is _______ A.
[10-Apr-2023 shift 1]
Q.11 Correct
Q.11 In-correct
Q.11 Unattempt
A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will
[10-Apr-2023 shift 2]
A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will
[10-Apr-2023 shift 2]
Q.12 Correct
Q.12 In-correct
Q.12 Unattempt
Given below are two statements:
Statement I : For diamagnetic substance, −1≤X<0, where X is the magnetic susceptibility.
Statement II : Diamagnetic substances when placed in an external magnetic field, tend to move from stronger to weaker part of the field.
In the light of the above statements, choose the correct answer from the options given below
[10-Apr-2023 shift 2]
Given below are two statements:
Statement I : For diamagnetic substance, −1≤X<0, where X is the magnetic susceptibility.
Statement II : Diamagnetic substances when placed in an external magnetic field, tend to move from stronger to weaker part of the field.
In the light of the above statements, choose the correct answer from the options given below
[10-Apr-2023 shift 2]
Q.13 Correct
Q.13 In-correct
Q.13 Unattempt
The free space inside a current carrying toroid is filled with a material of susceptibility 2×10−2. The percentage increase in the value of magnetic field inside the toroid will be
[11-Apr-2023 shift 1]
The free space inside a current carrying toroid is filled with a material of susceptibility 2×10−2. The percentage increase in the value of magnetic field inside the toroid will be
[11-Apr-2023 shift 1]
Q.14 Correct
Q.14 In-correct
Q.14 Unattempt
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : A bar magnet dropped through a metallic cylindrical pipe takes more time to come down compared to a non-magnetic bar with same geometry and mass.
Reason R : For the magnetic bar, Eddy currents are produced in the metallic pipe which oppose the motion of the magnetic bar.
In the light of the above statements, choose the correct answer from the options given below
[11-Apr-2023 shift 2]
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : A bar magnet dropped through a metallic cylindrical pipe takes more time to come down compared to a non-magnetic bar with same geometry and mass.
Reason R : For the magnetic bar, Eddy currents are produced in the metallic pipe which oppose the motion of the magnetic bar.
In the light of the above statements, choose the correct answer from the options given below
[11-Apr-2023 shift 2]
Q.15 Correct
Q.15 In-correct
Q.15 Unattempt
Given below are two statements:
Statements I : The diamagnetic property depends on temperature.
Statements II : The induced magnetic dipole moment in a diamagnetic sample is always opposite to the magnetizing field.
In the light of given statements, choose the correct answer from the options given below.
[12-Apr-2023 shift 1]
Given below are two statements:
Statements I : The diamagnetic property depends on temperature.
Statements II : The induced magnetic dipole moment in a diamagnetic sample is always opposite to the magnetizing field.
In the light of given statements, choose the correct answer from the options given below.
[12-Apr-2023 shift 1]
Q.16 Correct
Q.16 In-correct
Q.16 Unattempt
A compass needle oscillates 20 times per minute at a place where the dip is 30∘ and 30 times per minute where the dip is 60∘. The ratio of total magnetic field due to the earth at two places respectively is ‌
4
√x
. The value of x is
[12-Apr-2023 shift 1]
A compass needle oscillates 20 times per minute at a place where the dip is 30∘ and 30 times per minute where the dip is 60∘. The ratio of total magnetic field due to the earth at two places respectively is ‌
4
√x
. The value of x is
[12-Apr-2023 shift 1]
Q.17 Correct
Q.17 In-correct
Q.17 Unattempt
The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has
[24-Jun-2022-Shift-2]
The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has
[24-Jun-2022-Shift-2]
Q.18 Correct
Q.18 In-correct
Q.18 Unattempt
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 field.
Choose the correct answer from the options given below :
[25-Jun-2022-Shift-2]
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 field.
Choose the correct answer from the options given below :
[25-Jun-2022-Shift-2]
Q.19 Correct
Q.19 In-correct
Q.19 Unattempt
Given below two statements : One is labelled as Assertion (A) and other is labelled as Reason (R).
Assertion (A) : Non-polar materials do not have any permanent dipole moment.
Reason (R): When a non-polar material is placed in an electric field, the centre of the positive charge distribution of it's individual atom or molecule coincides with the centre of the negative charge distribution.
In the light of above statements, choose the most appropriate answer from the options given below.
[26-Jun-2022-Shift-1]
Given below two statements : One is labelled as Assertion (A) and other is labelled as Reason (R).
Assertion (A) : Non-polar materials do not have any permanent dipole moment.
Reason (R): When a non-polar material is placed in an electric field, the centre of the positive charge distribution of it's individual atom or molecule coincides with the centre of the negative charge distribution.
In the light of above statements, choose the most appropriate answer from the options given below.
[26-Jun-2022-Shift-1]
Q.20 Correct
Q.20 In-correct
Q.20 Unattempt
The susceptibility of a paramagnetic material is 99 . The permeability of the material in Wb/A-m, is :
[Permeability of free space µ0=4π×10−7‌Wb∕A−m ]
[27-Jun-2022-Shift-1]
The susceptibility of a paramagnetic material is 99 . The permeability of the material in Wb/A-m, is :
[Permeability of free space µ0=4π×10−7‌Wb∕A−m ]
[27-Jun-2022-Shift-1]
Q.21 Correct
Q.21 In-correct
Q.21 Unattempt
The space inside a straight current carrying solenoid is filled with a magnetic material having magnetic susceptibility equal to 1.2×10−5. What is fractional increase in the magnetic field inside solenoid with respect to air as medium inside the solenoid?
[28-Jun-2022-Shift-2]
The space inside a straight current carrying solenoid is filled with a magnetic material having magnetic susceptibility equal to 1.2×10−5. What is fractional increase in the magnetic field inside solenoid with respect to air as medium inside the solenoid?
[28-Jun-2022-Shift-2]
Q.22 Correct
Q.22 In-correct
Q.22 Unattempt
At a certain place the angle of dip is 30∘ and the horizontal component of earth's magnetic field is 0.5G. The earth's total magnetic field (in G), at that certain place, is :
[29-Jun-2022-Shift-1]
At a certain place the angle of dip is 30∘ and the horizontal component of earth's magnetic field is 0.5G. The earth's total magnetic field (in G), at that certain place, is :
[29-Jun-2022-Shift-1]
Q.23 Correct
Q.23 In-correct
Q.23 Unattempt
An electron with energy 0.1keV moves at right angle to the earth's magnetic field of 1×10−4Wbm−
2. The frequency of revolution of the electron will be
(Take mass of electron =9.0×10−31kg )
[25-Jul-2022-Shift-2]
An electron with energy 0.1keV moves at right angle to the earth's magnetic field of 1×10−4Wbm−
2. The frequency of revolution of the electron will be
(Take mass of electron =9.0×10−31kg )
[25-Jul-2022-Shift-2]
Q.24 Correct
Q.24 In-correct
Q.24 Unattempt
In a coil of resistance 8Ω, the magnetic flux due to an external magnetic field varies with time as φ=‌
2
3
(9−t2). The value of total heat produced in the coil, till the flux becomes zero, will be _________ J.
[26-Jul-2022-Shift-2]
In a coil of resistance 8Ω, the magnetic flux due to an external magnetic field varies with time as φ=‌
2
3
(9−t2). The value of total heat produced in the coil, till the flux becomes zero, will be _________ J.
[26-Jul-2022-Shift-2]
Q.25 Correct
Q.25 In-correct
Q.25 Unattempt
A magnet hung at 45∘ with magnetic meridian makes an angle of 60∘ with the horizontal. The actual value of the angle of dip is -
[27-Jul-2022-Shift-1]
A magnet hung at 45∘ with magnetic meridian makes an angle of 60∘ with the horizontal. The actual value of the angle of dip is -
[27-Jul-2022-Shift-1]
Q.26 Correct
Q.26 In-correct
Q.26 Unattempt
The magnetic field at the center of current carrying circular loop is B1. The magnetic field at a distance of √3 times radius of the given circular loop from the center on its axis is B2. The value of B1∕B2 will be
[28-Jul-2022-Shift-2]
The magnetic field at the center of current carrying circular loop is B1. The magnetic field at a distance of √3 times radius of the given circular loop from the center on its axis is B2. The value of B1∕B2 will be
[28-Jul-2022-Shift-2]
Q.27 Correct
Q.27 In-correct
Q.27 Unattempt
A wire of length 314‌cm carrying current of 14A is bent to form a circle. The magnetic moment of the coil is _______ A −m2. [Given .π=3.14]
[29-Jul-2022-Shift-1]
A wire of length 314‌cm carrying current of 14A is bent to form a circle. The magnetic moment of the coil is _______ A −m2. [Given .π=3.14]
[29-Jul-2022-Shift-1]
Q.28 Correct
Q.28 In-correct
Q.28 Unattempt
A wire X of length 50‌cm carrying a current of 2A is placed parallel to a long wire Y of length 5m. The wire Y carries a current of 3A. The distance between two wires is 5‌cm and currents flow in the same direction. The force acting on the wire Y is

[29-Jul-2022-Shift-2]
A wire X of length 50‌cm carrying a current of 2A is placed parallel to a long wire Y of length 5m. The wire Y carries a current of 3A. The distance between two wires is 5‌cm and currents flow in the same direction. The force acting on the wire Y is

[29-Jul-2022-Shift-2]
Q.29 Correct
Q.29 In-correct
Q.29 Unattempt
The vertical component of the earth's magnetic field is 6×10−5T at any place where the angle of dip is 37∘. The earth's resultant magnetic field at that place will be (Given tan‌37∘=‌
3
4
 )
[29-Jul-2022-Shift-2]
The vertical component of the earth's magnetic field is 6×10−5T at any place where the angle of dip is 37∘. The earth's resultant magnetic field at that place will be (Given tan‌37∘=‌
3
4
 )
[29-Jul-2022-Shift-2]
Q.30 Correct
Q.30 In-correct
Q.30 Unattempt
In a ferromagnetic material, below the Curie temperature, a domain is defined as
[25 Feb 2021 Shift 2]
In a ferromagnetic material, below the Curie temperature, a domain is defined as
[25 Feb 2021 Shift 2]
Q.31 Correct
Q.31 In-correct
Q.31 Unattempt
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 cannot be completely straight and confined.
C. Magnetic field lines are completely confined within a toroid.
D. Magnetic field lines inside a bar magnet are not parallel.
E. χ=−1 is the condition for a perfect diamagnetic material, where χ is its magnetic susceptibility.
Choose the correct answer from the options given below.
[18 Mar 2021 Shift 2]
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 cannot be completely straight and confined.
C. Magnetic field lines are completely confined within a toroid.
D. Magnetic field lines inside a bar magnet are not parallel.
E. χ=−1 is the condition for a perfect diamagnetic material, where χ is its magnetic susceptibility.
Choose the correct answer from the options given below.
[18 Mar 2021 Shift 2]
Q.32 Correct
Q.32 In-correct
Q.32 Unattempt
A bar magnet of length 14cm 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 18cm from the centre of the magnet. If BH=0.4G, then the magnetic moment of the magnet is (1G=10−4T)
[16 Mar 2021 Shift 1]
A bar magnet of length 14cm 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 18cm from the centre of the magnet. If BH=0.4G, then the magnetic moment of the magnet is (1G=10−4T)
[16 Mar 2021 Shift 1]
Q.33 Correct
Q.33 In-correct
Q.33 Unattempt
A solenoid of 1000 turns per metre has a core with relative permeability 500 . Insulated windings of the solenoid carry an electric current of 5A. The magnetic flux density produced by the solenoid is
(Permeability of free space =4π×10−7H/m )
[17 Mar 2021 Shift 1]
A solenoid of 1000 turns per metre has a core with relative permeability 500 . Insulated windings of the solenoid carry an electric current of 5A. The magnetic flux density produced by the solenoid is
(Permeability of free space =4π×10−7H/m )
[17 Mar 2021 Shift 1]
Q.34 Correct
Q.34 In-correct
Q.34 Unattempt
In a uniform magnetic field, the magnetic needle has a magnetic moment 9.85×10−2A∕m2 and moment of inertia 5×10−6kgm2. If it performs 10 complete oscillations in 5 seconds then themagnitude of the magnetic field is _______ mT
[Take π2 as 9.85]
[27 Jul 2021 Shift 1]
In a uniform magnetic field, the magnetic needle has a magnetic moment 9.85×10−2A∕m2 and moment of inertia 5×10−6kgm2. If it performs 10 complete oscillations in 5 seconds then themagnitude of the magnetic field is _______ mT
[Take π2 as 9.85]
[27 Jul 2021 Shift 1]
Q.35 Correct
Q.35 In-correct
Q.35 Unattempt
Choose the correct option :
[22 Jul 2021 Shift 2]
Choose the correct option :
[22 Jul 2021 Shift 2]
Q.36 Correct
Q.36 In-correct
Q.36 Unattempt
At an angle of 30° to the magnetic meridian, the apparent dip is 45°. Find the true dip:
[20 Jul 2021 Shift 2]
At an angle of 30° to the magnetic meridian, the apparent dip is 45°. Find the true dip:
[20 Jul 2021 Shift 2]
Q.37 Correct
Q.37 In-correct
Q.37 Unattempt
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 appropriate answer from the options given below :
[22 Jul 2021 Shift 2]
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 appropriate answer from the options given below :
[22 Jul 2021 Shift 2]
Q.38 Correct
Q.38 In-correct
Q.38 Unattempt
The magnetic susceptibility of a material of a rod is 499. Permeability in vacuum is 4π×10−7H∕m. Absolute permeability of the material of the rod is :
[20 Jul 2021 Shift 2]
The magnetic susceptibility of a material of a rod is 499. Permeability in vacuum is 4π×10−7H∕m. Absolute permeability of the material of the rod is :
[20 Jul 2021 Shift 2]
Q.39 Correct
Q.39 In-correct
Q.39 Unattempt
A long solenoid with 1000 turns/m has a core material with relative permeability 500 and volume 103cm3. If the core material is replaced by another material having relative permeability of 750 with same volume maintaining same current of 0.75A in the solenoid, the fractional change in the magnetic moment of the core would be approximately (
χ
499
). Find the value of χ.
[31 Aug 2021 Shift 2]
A long solenoid with 1000 turns/m has a core material with relative permeability 500 and volume 103cm3. If the core material is replaced by another material having relative permeability of 750 with same volume maintaining same current of 0.75A in the solenoid, the fractional change in the magnetic moment of the core would be approximately (
χ
499
). Find the value of χ.
[31 Aug 2021 Shift 2]
Q.40 Correct
Q.40 In-correct
Q.40 Unattempt

The figure gives experimentally measured B vs. H variation in a ferromagnetic material. The retentivity, co- ercivity and saturation, respectively, of the material are:
[7 Jan. 2020 II]

The figure gives experimentally measured B vs. H variation in a ferromagnetic material. The retentivity, co- ercivity and saturation, respectively, of the material are:
[7 Jan. 2020 II]
Q.41 Correct
Q.41 In-correct
Q.41 Unattempt
A small bar magnet placed with its axis at 30° with an external field of 0.06T experiences a torque of 0.018Nm. The minimum work required to rotate it from its stable to unstable equilibrium position is:
[Sep. 04, 2020 (I)]
A small bar magnet placed with its axis at 30° with an external field of 0.06T experiences a torque of 0.018Nm. The minimum work required to rotate it from its stable to unstable equilibrium position is:
[Sep. 04, 2020 (I)]
Q.42 Correct
Q.42 In-correct
Q.42 Unattempt
A circular coil has moment of inertia 0.8kgm2 around any diameter and is carrying current to produce a magnetic moment of 20Am2. The coil is kept initially in a vertical position and it can rotate freely around a horizontal diameter. When a uniform magnetic field of 4T is applied along the vertical, it starts rotating around its horizontal diameter. The angular speed the coil acquires after rotating by 60° will be:
[Sep. 04, 2020 (II)]
A circular coil has moment of inertia 0.8kgm2 around any diameter and is carrying current to produce a magnetic moment of 20Am2. The coil is kept initially in a vertical position and it can rotate freely around a horizontal diameter. When a uniform magnetic field of 4T is applied along the vertical, it starts rotating around its horizontal diameter. The angular speed the coil acquires after rotating by 60° will be:
[Sep. 04, 2020 (II)]
Q.43 Correct
Q.43 In-correct
Q.43 Unattempt
An iron rod of volume 10−3m3 and relative permeability 1000 is placed as core in a solenoid with 10 turns/cm. If a current of 0.5A is passed through the solenoid, then the magnetic moment of the rod will be :
[Sep. 05, 2020 (II)]
An iron rod of volume 10−3m3 and relative permeability 1000 is placed as core in a solenoid with 10 turns/cm. If a current of 0.5A is passed through the solenoid, then the magnetic moment of the rod will be :
[Sep. 05, 2020 (II)]
Q.44 Correct
Q.44 In-correct
Q.44 Unattempt
A paramagnetic sample shows a net magnetisation of 6 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 :
[Sep. 04, 2020 (II)]
A paramagnetic sample shows a net magnetisation of 6 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 :
[Sep. 04, 2020 (II)]
Q.45 Correct
Q.45 In-correct
Q.45 Unattempt
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
→
B
 . Then the field inside the paramagnetic substance is :

[Sep. 03, 2020 (II)]
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
→
B
 . Then the field inside the paramagnetic substance is :

[Sep. 03, 2020 (II)]
Q.46 Correct
Q.46 In-correct
Q.46 Unattempt
Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required?
[Sep. 02, 2020 (I)]
Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required?
[Sep. 02, 2020 (I)]
Q.47 Correct
Q.47 In-correct
Q.47 Unattempt
A ring is hung on a nail. It can oscillate, without slipping or sliding (i) in its plane with a time period T1 and, (ii) back and forth in a direction perpendicular to its plane, with a period T2 . The ratio
T1
T2
 will be :
[Sep. 05, 2020 (II)]
A ring is hung on a nail. It can oscillate, without slipping or sliding (i) in its plane with a time period T1 and, (ii) back and forth in a direction perpendicular to its plane, with a period T2 . The ratio
T1
T2
 will be :
[Sep. 05, 2020 (II)]
Q.48 Correct
Q.48 In-correct
Q.48 Unattempt
A magnet of total magnetic moment 10−2
^
i
 A−m2 is placed in a time varying magnetic field,B
^
i
(cos‌ω‌t) where B=1 Tesla and ω=0.125rad∕s. The work done for reversing the direction of the magnetic moment at t=1 second, is:
[10 Jan. 2019 I]
A magnet of total magnetic moment 10−2
^
i
 A−m2 is placed in a time varying magnetic field,B
^
i
(cos‌ω‌t) where B=1 Tesla and ω=0.125rad∕s. The work done for reversing the direction of the magnetic moment at t=1 second, is:
[10 Jan. 2019 I]
Q.49 Correct
Q.49 In-correct
Q.49 Unattempt
A paramagnetic material has 1028 atoms /m3. Its magnetic susceptibility at temperature 350K is 2.8×10−4. Its susceptibility at 300K is:
[12 Jan. 2019 II]
A paramagnetic material has 1028 atoms /m3. Its magnetic susceptibility at temperature 350K is 2.8×10−4. Its susceptibility at 300K is:
[12 Jan. 2019 II]
Q.50 Correct
Q.50 In-correct
Q.50 Unattempt
A paramagnetic substance in the form of a cube with sides 1cm has a magnetic dipole moment of 20×10−6J∕T when a magnetic intensity of 60×103A∕m is applied. Its magnetic susceptibility is:
[11 Jan. 2019 II]
A paramagnetic substance in the form of a cube with sides 1cm has a magnetic dipole moment of 20×10−6J∕T when a magnetic intensity of 60×103A∕m is applied. Its magnetic susceptibility is:
[11 Jan. 2019 II]
Q.51 Correct
Q.51 In-correct
Q.51 Unattempt
At some location on earth the horizontal component of earth's magnetic field is 18×10−6T. At this location, magnetic needle of length 0.12m and pole strength 1.8 Am is suspended from its mid-point using a thread, it makes 45° angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force that should be applied at one of its ends is:
[10 Jan. 2019 II]
At some location on earth the horizontal component of earth's magnetic field is 18×10−6T. At this location, magnetic needle of length 0.12m and pole strength 1.8 Am is suspended from its mid-point using a thread, it makes 45° angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force that should be applied at one of its ends is:
[10 Jan. 2019 II]
Q.52 Correct
Q.52 In-correct
Q.52 Unattempt
A bar magnet is demagnetized by inserthing it inside a solenoid of length 0.2 m, 100 turns, and carrying a current of 5.2 A. The coercivity of the bar magnet is:
[9 Jan. 2019 I]
A bar magnet is demagnetized by inserthing it inside a solenoid of length 0.2 m, 100 turns, and carrying a current of 5.2 A. The coercivity of the bar magnet is:
[9 Jan. 2019 I]
Q.53 Correct
Q.53 In-correct
Q.53 Unattempt
A hoop and a solid cylinder of same mass and radius are made of a permanent magnetic material with their magnetic moment parallel to their respective axes. But the magnetic moment of hoop is twice of solid cylinder. They are placed in a uniform magnetic field in such a manner that their magnetic moments make a small angle with the field. If the oscillation periods of hoop and cylinder are Th and Tc respectively, then:
[10 Jan. 2019 II]
A hoop and a solid cylinder of same mass and radius are made of a permanent magnetic material with their magnetic moment parallel to their respective axes. But the magnetic moment of hoop is twice of solid cylinder. They are placed in a uniform magnetic field in such a manner that their magnetic moments make a small angle with the field. If the oscillation periods of hoop and cylinder are Th and Tc respectively, then:
[10 Jan. 2019 II]
Q.54 Correct
Q.54 In-correct
Q.54 Unattempt
Two magnetic dipoles X and Y are placed at a separation d, with their axes perpendicular to each other. The dipole moment of Y is twice that of X. A particle of charge q is passing through their midpoint P, at angle θ=45° with the horizontal line, as shown in figure. What would be the magnitude of force on the particle at that instant? (d is much larger than the dimensions of the dipole)

[8 April 2019 II]
Two magnetic dipoles X and Y are placed at a separation d, with their axes perpendicular to each other. The dipole moment of Y is twice that of X. A particle of charge q is passing through their midpoint P, at angle θ=45° with the horizontal line, as shown in figure. What would be the magnitude of force on the particle at that instant? (d is much larger than the dimensions of the dipole)

[8 April 2019 II]
Q.55 Correct
Q.55 In-correct
Q.55 Unattempt
A magnetic compass needle oscillates 30 times per minute at a place where the dip is 45° , and 40 times per minute where the dip is 30° . If B1 and B2 are respectively the total magnetic field due to the earth and the two places, then the ratio B1∕B2 is best given by :
[12 April 2019 I]
A magnetic compass needle oscillates 30 times per minute at a place where the dip is 45° , and 40 times per minute where the dip is 30° . If B1 and B2 are respectively the total magnetic field due to the earth and the two places, then the ratio B1∕B2 is best given by :
[12 April 2019 I]
Q.56 Correct
Q.56 In-correct
Q.56 Unattempt
The B-H curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/cm.. The current that should be passed in the solenoid to demagnetise the ferromagnet completely is:

[Online April 15, 2018]
The B-H curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/cm.. The current that should be passed in the solenoid to demagnetise the ferromagnet completely is:

[Online April 15, 2018]
Q.57 Correct
Q.57 In-correct
Q.57 Unattempt
A magnetic dipole in a constant magnetic field has :
[Online April 8, 2017]
A magnetic dipole in a constant magnetic field has :
[Online April 8, 2017]
Q.58 Correct
Q.58 In-correct
Q.58 Unattempt
A magnetic needle of magnetic moment 6.7×10–2Am2 and moment of inertia 7.5×10−6kgm2 is performing simple harmonic oscillations in a magnetic field of 0.01 T. Time taken for 10 complete oscillations is :
[2017]
A magnetic needle of magnetic moment 6.7×10–2Am2 and moment of inertia 7.5×10−6kgm2 is performing simple harmonic oscillations in a magnetic field of 0.01 T. Time taken for 10 complete oscillations is :
[2017]
Q.59 Correct
Q.59 In-correct
Q.59 Unattempt
A magnetic dipole is acted upon by two magnetic fields which are inclined to each other at an angle of 75°. One of the fields has a magnitude of 15 mT. The dipole attains stable equilibrium at an angle of 30° with this field. The magntidue of the other field (in mT) is close to :
[Online April 9, 2016]
A magnetic dipole is acted upon by two magnetic fields which are inclined to each other at an angle of 75°. One of the fields has a magnitude of 15 mT. The dipole attains stable equilibrium at an angle of 30° with this field. The magntidue of the other field (in mT) is close to :
[Online April 9, 2016]
Q.60 Correct
Q.60 In-correct
Q.60 Unattempt
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 :
[2016]
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 :
[2016]
Q.61 Correct
Q.61 In-correct
Q.61 Unattempt
A fighter plane of length 20m, wing span (distance from tip of one wing to the tip of the other wing) of 15m and height 5m is lying towards east over Delhi. Its speed is 240ms−1. The earth's magnetic field over Delhi is 5× 10−5T with the declination angle ∼0° and dip of θ such that sin‌θ=
2
3
. If the voltage developed is VB between the lower and upper side of the plane and VW between the tips of the wings then VB and VW are close to :
[Online April 10, 2016]
A fighter plane of length 20m, wing span (distance from tip of one wing to the tip of the other wing) of 15m and height 5m is lying towards east over Delhi. Its speed is 240ms−1. The earth's magnetic field over Delhi is 5× 10−5T with the declination angle ∼0° and dip of θ such that sin‌θ=
2
3
. If the voltage developed is VB between the lower and upper side of the plane and VW between the tips of the wings then VB and VW are close to :
[Online April 10, 2016]
Q.62 Correct
Q.62 In-correct
Q.62 Unattempt
A 25cm long solenoid has radius 2cm and 500 total number of turns. It carries a current of 15A. If it is equivalent to a magnet of the same size and magnetization
→
M
 (magnetic moment/volume), then |
→
M
| is :
[Online April 10, 2015]
A 25cm long solenoid has radius 2cm and 500 total number of turns. It carries a current of 15A. If it is equivalent to a magnet of the same size and magnetization
→
M
 (magnetic moment/volume), then |
→
M
| is :
[Online April 10, 2015]
Q.63 Correct
Q.63 In-correct
Q.63 Unattempt
A short bar magnet is placed in the magnetic meridian of the earth with north pole pointing north. Neutral points are found at a distance of 30 cm from the magnet on the East – West line, drawn through the middle point of the magnet. The magnetic moment of the magnet in Am2 is close to: ( Given
µ0
4π
=10−7 in SI units and BH= Horizontal component of earth’s magnetic field =3.6×10–5 tesla)
[Online April 11, 2015]
A short bar magnet is placed in the magnetic meridian of the earth with north pole pointing north. Neutral points are found at a distance of 30 cm from the magnet on the East – West line, drawn through the middle point of the magnet. The magnetic moment of the magnet in Am2 is close to: ( Given
µ0
4π
=10−7 in SI units and BH= Horizontal component of earth’s magnetic field =3.6×10–5 tesla)
[Online April 11, 2015]
Q.64 Correct
Q.64 In-correct
Q.64 Unattempt
The coercivity of a small magnet where the ferromagnet gets demagnetized is 3×103Am−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:
[2014]
The coercivity of a small magnet where the ferromagnet gets demagnetized is 3×103Am−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:
[2014]
Q.65 Correct
Q.65 In-correct
Q.65 Unattempt
An example of a perfect diamagnet is a superconductor. This implies that when a superconductor is put in a magnetic field of intensity B, the magnetic field Bs inside the superconductor will be such that:
[Online April 19, 2014]
An example of a perfect diamagnet is a superconductor. This implies that when a superconductor is put in a magnetic field of intensity B, the magnetic field Bs inside the superconductor will be such that:
[Online April 19, 2014]
Q.66 Correct
Q.66 In-correct
Q.66 Unattempt
Three identical bars A, B and C are made of different magnetic materials. When kept in a uniform magnetic field, the field lines around them look as follows:
Make the correspondence of these bars with their material being diamagnetic (D), ferromagnetic (F) and paramagnetic (P):
[Online April 11, 2014]
Three identical bars A, B and C are made of different magnetic materials. When kept in a uniform magnetic field, the field lines around them look as follows:

Make the correspondence of these bars with their material being diamagnetic (D), ferromagnetic (F) and paramagnetic (P):
[Online April 11, 2014]
Q.67 Correct
Q.67 In-correct
Q.67 Unattempt
The magnetic field of earth at the equator is approximately 4×10−5T. The radius of earth is 6.4‌times‌106‌m. Then the dipole moment of the earth will be nearly of the order of:
[Online April 9, 2014]
The magnetic field of earth at the equator is approximately 4×10−5T. The radius of earth is 6.4‌times‌106‌m. Then the dipole moment of the earth will be nearly of the order of:
[Online April 9, 2014]
Q.68 Correct
Q.68 In-correct
Q.68 Unattempt
The mid points of two small magnetic dipoles of length d in end-on positions, are separated by a distance x, (x > > d). The force between them is proportional to x–n where n is:

[Online April 9, 2014]
The mid points of two small magnetic dipoles of length d in end-on positions, are separated by a distance x, (x > > d). The force between them is proportional to x–n where n is:

[Online April 9, 2014]
Q.69 Correct
Q.69 In-correct
Q.69 Unattempt
Two short bar magnets of length 1cm each have magnetic moments 1.20Am2 and 1.00Am2 respectively. They are placed on a horizontal table parallel to each other with their N poles pointing towards the South. They have a common magnetic equator and are separated by a distance of 20.0cm. The value of the resultant horizontal magnetic induction at the mid-point O of the line joining their centres is close to (Horizontal component of earth's magnetic induction is 3.6×10.5Wb∕m2 )
[2013]
Two short bar magnets of length 1cm each have magnetic moments 1.20Am2 and 1.00Am2 respectively. They are placed on a horizontal table parallel to each other with their N poles pointing towards the South. They have a common magnetic equator and are separated by a distance of 20.0cm. The value of the resultant horizontal magnetic induction at the mid-point O of the line joining their centres is close to (Horizontal component of earth's magnetic induction is 3.6×10.5Wb∕m2 )
[2013]
Q.70 Correct
Q.70 In-correct
Q.70 Unattempt
The earth’s magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to 8×1022Am2 , the value of earth’s magnetic field near the equator is close to (radius of the earth =6.4×106 m)
[Online April 25, 2013]
The earth’s magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to 8×1022Am2 , the value of earth’s magnetic field near the equator is close to (radius of the earth =6.4×106 m)
[Online April 25, 2013]
Q.71 Correct
Q.71 In-correct
Q.71 Unattempt
A bar magnet of length 6cm has a magnetic moment of 4JT−1. Find the strength of magnetic field at a distance of 200cm from the centre of the magnet along its equatorial line.
[Online May 7, 2012]
A bar magnet of length 6cm has a magnetic moment of 4JT−1. Find the strength of magnetic field at a distance of 200cm from the centre of the magnet along its equatorial line.
[Online May 7, 2012]
Q.72 Correct
Q.72 In-correct
Q.72 Unattempt
A thin circular disc of radius R is uniformly charged with density σ>0 per unit area. The disc rotates about its axis with a uniform angular speed ω. The magnetic moment of the disc is
[2011 RS]
A thin circular disc of radius R is uniformly charged with density σ>0 per unit area. The disc rotates about its axis with a uniform angular speed ω. The magnetic moment of the disc is
[2011 RS]
Q.73 Correct
Q.73 In-correct
Q.73 Unattempt
Relative permittivity and permeability of a material εr and µr, respectively. Which of the following values of these quantities are allowed for a diamagnetic material?
[2008]
Relative permittivity and permeability of a material εr and µr, respectively. Which of the following values of these quantities are allowed for a diamagnetic material?
[2008]
Q.74 Correct
Q.74 In-correct
Q.74 Unattempt
Needles N1,N2 and N3 are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will
[2006]
Needles N1,N2 and N3 are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will
[2006]
Q.75 Correct
Q.75 In-correct
Q.75 Unattempt
The materials suitable for making electromagnets should have
[2006]
The materials suitable for making electromagnets should have
[2006]
Q.76 Correct
Q.76 In-correct
Q.76 Unattempt
A magnetic needle is kept in a non-uniform magnetic field. It experiences
[2005]
A magnetic needle is kept in a non-uniform magnetic field. It experiences
[2005]
Q.77 Correct
Q.77 In-correct
Q.77 Unattempt
The length of a magnet is large compared to its width and breadth. The time period of its oscillation in a vibration magnetometer is 2s. The magnet is cut along its length into three equal parts and these parts are then placed on each other with their like poles together. The time period of this combination will be
[2004]
The length of a magnet is large compared to its width and breadth. The time period of its oscillation in a vibration magnetometer is 2s. The magnet is cut along its length into three equal parts and these parts are then placed on each other with their like poles together. The time period of this combination will be
[2004]
Q.78 Correct
Q.78 In-correct
Q.78 Unattempt
A magnetic needle lying parallel to a magnetic field requires W units of work to turn it through 60° . The torque needed to maintain the needle in this position will be
[2003]
A magnetic needle lying parallel to a magnetic field requires W units of work to turn it through 60° . The torque needed to maintain the needle in this position will be
[2003]
Q.79 Correct
Q.79 In-correct
Q.79 Unattempt
The magnetic lines of force inside a bar magnet
[2003]
The magnetic lines of force inside a bar magnet
[2003]
Q.80 Correct
Q.80 In-correct
Q.80 Unattempt
A thin rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely in the same field. If its period of oscillation is T′, the ratio
T′
T
 is
[2003]
A thin rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely in the same field. If its period of oscillation is T′, the ratio
T′
T
 is
[2003]
Q.81 Correct
Q.81 In-correct
Q.81 Unattempt
Curie temperature is the temperature above which
[2003]
Curie temperature is the temperature above which
[2003]
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