Question 1: Palette 1/66

JEE Mains 2026 MCQ

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 way that they spontaneously align themselves forming domains.

Reason (R) : At high enough temperature, the domain structure of ferromagnetic material disintegrates. Thus, magnetization will disappear at high enough temperature known as Curie temperature.

In the light of the above statements, choose the correct answer from the options given below :

A

(A) is true but (R) is false

B

Both (A) and (R) are true and (R) is the correct explanation of (A)

C

(A) is false but (R) is true

D

Both (A) and (R) are true but (R) is not the correct explanation of (A)

Question 2: Palette 2/66

JEE Mains 2026 MCQ

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 in SI units is $\alpha \times 10^5$. The value of $\alpha$ is $\_\_\_\_$ .

(Free space permeability $\mu_0=4 \pi \times 10^{-7}$ SI units.)

A

$\frac{25}{\pi}$

B

$\frac{1}{16 \pi}$

C

$\frac{1}{\pi}$

D

$\frac{1}{4 \pi}$

Question 3: Palette 3/66

JEE Mains 2025 MCQ

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:

A

Both (A) and (R) are correct and (R) is the correct explanation of (A)

B

(A) is not correct but (R) is correct

C

(A) is correct but (R) is not correct

D

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

Question 4: Palette 4/66

JEE Mains 2025 MCQ

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 :

A

$\frac{5}{3} \times 10^{-5} \%$

B

$\frac{5}{6} \times 10^{-4} \%$

C

$\frac{5}{6} \times 10^{-5} \%$

D

$\frac{6}{5} \times 10^{-3} \%$

Question 5: Palette 5/66

JEE Mains 2025 MCQ

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 :

A

$ \text { }-40 \sqrt{3} \mathrm{~J} $

B

-80 J

C

80 J

D

-60 J

Question 6: Palette 6/66

JEE Mains 2025 MCQ

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)

A

$X=\frac{\mu}{\mu_0}-1$

B

$X=\frac{\mu_{\mathrm{r}}}{\mu_0}+1$

C

$\chi=\mu_r+1$

D

$X=1-\frac{\mu}{\mu_0}$

Question 7: Palette 7/66

JEE Mains 2025 MCQ

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:

A

(A)-(III), (B)-(IV), (C)-(II), (D)-(I)

B

(A)-(III), (B)-(II), (C)-(I), (D)-(IV)

C

(A)-(III), (B)-(IV), (C)-(I), (D)-(II)

D

(A)-(I), (B)-(II), (C)-(III), (D)-(IV)

Question 8: Palette 8/66

JEE Mains 2025 MSQ

A bar magnet has total length $2 l=20$ units and the field point P is at a distance $\mathrm{d}=10$ units from the centre of the magnet. If the relative uncertainty of length measurement is $1 \%$, then uncertainty of the magnetic field at point P is :

A

10%

B

5%

C

3%

D

4%

Question 9: Palette 9/66

JEE Mains 2024 MCQ

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 appropriate answer from the options given below:

A

A, B, C Only

B

A, C Only

C

A, B, C, D

D

B, D Only

Question 10: Palette 10/66

JEE Mains 2024 MCQ

Match List I with List II:

	LIST I (Y vs X)		LIST II (Shape of Graph)
A.	Y-magnetic susceptibility X = magnetising field	I.
B.	Y = magnetic field X = distance from centre of a current carrying wire for x < a (where a = radius of wire)	II.
C.	Y = magnetic field $\mathrm{X}=$ distance from centre of a current carrying wire for $x>\mathrm{a}$ (where $\mathrm{a}=$ radius of wire)	III.
D.	Y = magnetic field inside solenoid X = distance from centre	IV.

Choose the correct answer from the options given below :

A

(A)-(III), (B)-(IV), (C)- (I), (D)-(II)

B

(A)-(III), (B)-(I), (C)-(IV), (D)-(II)

C

(A)-(IV), (B)-(I), (C)-(III), (D)-(II)

D

(A)-(I), (B)-(III), (C)-(II), (D)-(IV)

Question 11: Palette 11/66

JEE Mains 2024 MCQ

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:

A

$4 \times 10^{-2} \mathrm{~J}$

B

$16 \times 10^{-2} \mathrm{~J}$

C

$8 \times 10^{-2} \mathrm{~J}$

D

Zero

Question 12: Palette 12/66

JEE Mains 2023 MCQ

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 statements, choose the correct answer from the options given below.

A

Statement I is incorrect but Statement II is true.

B

Statement I is correct but Statement II is false.

C

Both Statement I and Statement II are False.

D

Both Statement I and Statement II are true.

Question 13: Palette 13/66

JEE Mains 2023 MCQ

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

A

0.1%

B

1%

C

2%

D

0.2%

Question 14: Palette 14/66

JEE Mains 2023 MCQ

A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will

A

move down with almost constant speed

B

move down with an acceleration equal to $\mathrm{g}$

C

move down with an acceleration greater than $\mathrm{g}$

D

oscillate inside the tube

Question 15: Palette 15/66

JEE Mains 2023 MCQ

Given below are two statements:

Statement I : For diamagnetic substance, $-1 \leq \chi < 0$, where $\chi$ 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

A

Both Statement I and Statement II are true

B

Statement I is correct but Statement II is false

C

Both Statement I and Statement II are False

D

Statement I is incorrect but Statement II is true.

Question 16: Palette 16/66

JEE Mains 2023 MCQ

Given below are two statements: one is labelled as Assertion $\mathbf{A}$ and the other is labelled as Reason $\mathbf{R}$

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 answer from the options given below.

A

Both A and R are correct and R is the correct explanation of A

B

A is not correct but R is correct

C

A is correct but R is not correct

D

Both A and R are correct but R is NOT the correct explanation of A

Question 17: Palette 17/66

JEE Mains 2023 MCQ

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

A

zero

B

1 J

C

2 J

D

4 J

Question 18: Palette 18/66

JEE Mains 2023 MCQ

A solenoid of 1200 turns is wound uniformly in a single layer on a glass tube 2 m long and 0.2 m in diameter. The magnetic intensity at the center of the solenoid when a current of 2 A flows through it is :

A

$\mathrm{1~A~m^{-1}}$

B

$\mathrm{2.4\times10^{-3}~A~m^{-1}}$

C

$\mathrm{1.2\times10^{3}~A~m^{-1}}$

D

$\mathrm{2.4\times10^{3}~A~m^{-1}}$

Question 19: Palette 19/66

JEE Mains 2022 MCQ

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 $\left(\right.$Given $\left.\tan 37^{\circ}=\frac{3}{4}\right)$

A

$8 \times 10^{-5} \mathrm{~T}$

B

$6 \times 10^{-5} \mathrm{~T}$

C

$5 \times 10^{-4} \mathrm{~T}$

D

$1 \times 10^{-4} \mathrm{~T}$

Question 20: Palette 20/66

JEE Mains 2022 MCQ

A compass needle of oscillation magnetometer oscillates 20 times per minute at a place $\mathrm{P}$ of $\operatorname{dip} 30^{\circ}$. The number of oscillations per minute become 10 at another place $\mathrm{Q}$ of $60^{\circ}$ dip. The ratio of the total magnetic field at the two places $\left(B_{Q}: B_{P}\right)$ is :

A

$\sqrt{3}: 4$

B

$4: \sqrt{3}$

C

$\sqrt{3}: 2$

D

$2: \sqrt{3}$

Question 21: Palette 21/66

JEE Mains 2022 MCQ

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

A

2 : 1

B

8 : 3

C

1 : 3

D

27 : 16

Question 22: Palette 22/66

JEE Mains 2022 MCQ

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

$\tan ^{-1}\left(\sqrt{\frac{3}{2}}\right)$

B

$\tan ^{-1}(\sqrt{6})$

C

$\tan ^{-1}\left(\sqrt{\frac{2}{3}}\right)$

D

$ \tan ^{-1}\left(\sqrt{\frac{1}{2}}\right) $

Question 23: Palette 23/66

JEE Mains 2022 MCQ

An electron with energy 0.1 keV moves at right angle to the earth's magnetic field of 1 $\times$ 10^$-$4 Wbm^$-$2. The frequency of revolution of the electron will be :

(Take mass of electron = 9.0 $\times$ 10^$-$31 kg)

A

$1.6 \times 10^{5} \mathrm{~Hz}$

B

$5.6 \times 10^{5} \mathrm{~Hz}$

C

$2.8 \times 10^{6} \mathrm{~Hz}$

D

$1.8 \times 10^{6} \mathrm{~Hz}$

Question 24: Palette 24/66

JEE Mains 2022 MCQ

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 :

A

${1 \over {\sqrt 3 }}$

B

${1 \over 2}$

C

$\sqrt 3 $

D

1

Question 25: Palette 25/66

JEE Mains 2022 MCQ

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

1.2 $\times$ 10^$-$5

B

1.2 $\times$ 10^$-$3

C

1.8 $\times$ 10^$-$3

D

2.4 $\times$ 10^$-$5

Question 26: Palette 26/66

JEE Mains 2022 MCQ

The susceptibility of a paramagnetic material is 99. The permeability of the material in Wb/A-m, is :

[Permeability of free space $\mu$₀ = 4$\pi$ $\times$ 10^$-$7 Wb/A-m]

A

4$\pi$ $\times$ 10^$-$7

B

4$\pi$ $\times$ 10^$-$4

C

4$\pi$ $\times$ 10^$-$5

D

4$\pi$ $\times$ 10^$-$6

Question 27: Palette 27/66

JEE Mains 2022 MCQ

A bar magnet having a magnetic moment of 2.0 $\times$ 10⁵ 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 :

A

14 J

B

8.4 J

C

4 J

D

1.4 J

Question 28: Palette 28/66

JEE Mains 2022 MCQ

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 :

A

Both Statement I and Statement II are true.

B

Both Statement I and Statement II are false.

C

Statement I is true but Statement II is false.

D

Statement I is false but Statement II is true.

Question 29: Palette 29/66

JEE Mains 2022 MCQ

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

A

low coercivity and high retentivity.

B

low coercivity and low permeability.

C

high permeability and low retentivity.

D

high permeability and high retentivity.

Question 30: Palette 30/66

JEE Mains 2021 MCQ

Following plots show magnetization (M) vs magnetizing field (H) and magnetic susceptibility ($\chi $) vs temperature (T) graph :


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

A

(a), (c)

B

(a), (d)

C

(b), (d)

D

(b), (c)

Question 31: Palette 31/66

JEE Mains 2021 MCQ

Choose the correct option

A

True dip is always equal to apparent dip.

B

True dip is not mathematically related to apparent dip.

C

True dip is less than the apparent dip.

D

True dip is always greater than the apparent dip.

Question 32: Palette 32/66

JEE Mains 2021 MCQ

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 :

A

Statement I is false but Statement II is true

B

Statement I is true but Statement II is false

C

Both Statement I and Statement II are false

D

Both Statement I and Statement II are true

Question 33: Palette 33/66

JEE Mains 2021 MCQ

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

A

${\tan ^{ - 1}}\sqrt 3 $

B

${\tan ^{ - 1}}{1 \over {\sqrt 3 }}$

C

${\tan ^{ - 1}}{2 \over {\sqrt 3 }}$

D

${\tan ^{ - 1}}{{\sqrt 3 } \over 2}$

Question 34: Palette 34/66

JEE Mains 2021 MCQ

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

A

4$\pi$ $\times$ 10^$-$4 H/m

B

2$\pi$ $\times$ 10^$-$4 H/m

C

3$\pi$ $\times$ 10^$-$4 H/m

D

$\pi$ $\times$ 10^$-$4 H/m

Question 35: Palette 35/66

JEE Mains 2021 MCQ

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) $\chi $ = $-$1 is the condition for a perfect diamagnetic material, where x is its magnetic susceptibility.

Choose the correct answer from the options given below :

A

(A) and (B) only

B

(B) and (C) only

C

(C) and (E) only

D

(B) and (D) only

Question 36: Palette 36/66

JEE Mains 2021 MCQ

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 center of the magnet. If B_H = 0.4 G, the magnetic moment of the magnet is : (1G = 10^$-$4 T)

A

2.880 $\times$ 10² J T^$-$1

B

2.880 J T^$-$1

C

2.880 $\times$ 10³ J T^$-$1

D

28.80 J T^$-$1

Question 37: Palette 37/66

JEE Mains 2021 MCQ

In a ferromagnetic material, below the curie temperature, a domain is defined as :

A

a macroscopic region with zero magnetization.

B

a macroscopic region with saturation magnetization.

C

a macroscopic region with randomly oriented magnetic dipoles.

D

a macroscopic region with consecutive magnetic dipoles oriented in opposite direction.

Question 38: Palette 38/66

JEE Mains 2021 MCQ

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

A

may increase or decrease in size and change its orientation.

B

increase in size but no change in orientation.

C

decrease in size and changes orientation.

D

have no relation with external magnetic field.

Question 39: Palette 39/66

JEE Mains 2020 MCQ

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:

A

4 A/m

B

1 A/m

C

0.75 A/m

D

2.25 A/m

Question 40: Palette 40/66

JEE Mains 2020 MCQ

A small bar magnet placed with its axis
at 30^o 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

6.4 $ \times $ 10^-2 J

B

9.2 $ \times $ 10^-3 J

C

7.2 $ \times $ 10^-2 J

D

11.7 $ \times $ 10^-3 J

Question 41: Palette 41/66

JEE Mains 2020 MCQ

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 $\overrightarrow B $ . Then the field inside the paramagnetic substance is :

A

$\overrightarrow B $

B

zero

C

much large than $\left| {\overrightarrow B } \right|$ and parallel to $\overrightarrow B $

D

much large than $\left| {\overrightarrow B } \right|$ but opposite to $\overrightarrow B $

Question 42: Palette 42/66

JEE Mains 2020 MCQ

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?

A

T : Large retentivity, small coercivity

B

P : Large retentivity, large coercivity

C

P : Small retentivity, large coercivity

D

T : Large retentivity, large coercivity

Question 43: Palette 43/66

JEE Mains 2020 MCQ

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

A

1.0 T, 50A/m and 1.5 T

B

1.5 T, 50 A/m and 1.0 T

C

1.5 T, 50 A/m and 2.0 T

D

150 A/m, 1.0 T and 1.5 T

Question 44: Palette 44/66

JEE Mains 2019 MCQ

A magnetic compass needle oscillates 30 times per minute at a place where the dip is 45^o, and 40 times per minute where the dip is 30^o. If B₁ and B₂ are respectively the total magnetic field due to the earth at the two places, then the ratio ${{{B_1}} \over {{B_2}}}$ is best given by :

A

1.8

B

2.2

C

0.7

D

3.6

Question 45: Palette 45/66

JEE Mains 2019 MCQ

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 q = 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)

A

$ \left( {{{{\mu _0}} \over {4\pi }}} \right){2M \over {{{\left( {d/2} \right)}^3}}} \times qv$

B

$ \left( {{{{\mu _0}} \over {4\pi }}} \right){M \over {{{\left( {d/2} \right)}^3}}} \times qv$

C

$\sqrt 2 \left( {{{{\mu _0}} \over {4\pi }}} \right){M \over {{{\left( {d/2} \right)}^3}}} \times qv$

D

0

Question 46: Palette 46/66

JEE Mains 2019 MCQ

A paramagnetic material has 10²⁸ atoms/m³. Its magnetic susceptibility at temperature 350 K is 2.8 $ \times $ 10^–4. Its susceptibility at 300 K is :

A

3.726 $ \times $ 10^–4

B

2.672 $ \times $ 10^–4

C

3.672 $ \times $ 10^–4

D

3.267 $ \times $ 10^$-$4

Question 47: Palette 47/66

JEE Mains 2019 MCQ

A paramagnetic substance in the form of a cube with sides 1 cm has a magnetic dipole moment of 20 $ \times $ 10^–6 J/ T when a magnetic intensity of 60 $ \times $ 10³ A/m is applied. Its magnetic susceptibility is

A

3.3 $ \times $ 10^–4

B

2.3 $ \times $ 10^–2

C

4.3 $ \times $ 10^–2

D

3.3 $ \times $ 10^–2

Question 48: Palette 48/66

JEE Mains 2019 MCQ

At some location on earth, the horizontal component of earth’s magnetic field is 18 × 10^–6 T. At this location, magnetic needle of length 0.12 m and pole strength 1.8 Am is suspended from its mid-point using a thread, it makes 45^o angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force that should be applied at one of its ends is -

A

3.6 $ \times $ 10^$-$5 N

B

1.8 $ \times $ 10^$-$5 N

C

1.3 $ \times $ 10^$-$5 N

D

6.5 $ \times $ 10^$-$5 N

Question 49: Palette 49/66

JEE Mains 2019 MCQ

A magnet of total magnetic moment 10^-2 ${\widehat i}$ A-m² is placed in a time varying magnetic field, B${\widehat i}$ (cos $\omega t$) where B = 1 Tesla and $\omega $ = 0.125 rad/s. The work done for reversing the direction of the magnetic moment at t = 1 second, is -

A

0.014 J

B

0.028 J

C

0.01 J

D

0.007 J

Question 50: Palette 50/66

JEE Mains 2019 MCQ

A bar magnet is demagnetized by inserting it inside a solenoid of length 0.2 m, 100 turns, and carrying a current of 5.2 A. The corecivity of the bar magnet is :

A

285 A/m

B

2600 A/m

C

520 A/m

D

1200 A/m

Question 51: Palette 51/66

JEE Mains 2018 MCQ

The $B$-$H$ curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solended with $1000$ turns/cm. The current that should be passed in the solended to demagnetise the ferromagnet completely is :

A

$1$ $mA$

B

$2$ $mA$

C

$20\,\mu A$

D

$40\,\mu A$

Question 52: Palette 52/66

JEE Mains 2017 MCQ

A magnetic needle of magnetic moment 6.7 $\times$ 10^-2 A m² and moment of inertia 7.5 $\times$ 10^-6 kg m² is performing simple harmonic oscillations in a magnetic field of 0.01 T. Time taken for 10 complete oscillations is:

A

8.76 s

B

6.65 s

C

8.89 s

D

6.98 s

Question 53: Palette 53/66

JEE Mains 2016 MCQ

A fighter plane of length 20 m, wing span (distance from tip of one wing to the tip of the other wing) of 15 m and height 5 m is flying towards east over Delhi. Its speed is 240 ms⁻¹. The earth’s magnetic field over Delhi is 5 $ \times $10⁻⁵ T with the declination angle ~ 0^o and dip of $\theta $ such that sin $\theta $ = 2/3 . If the voltage developed is V_B between the lower and upper side of the plane and V_W between the tips of the wings then V_B and V_W are close to :

A

V_B = 45 m_V; V_W = 120 m_V with right side of pilot at higher voltage

B

V_B = 45 m_V; V_W = 120 m_V with left side of pilot at higher voltage

C

V_B = 40 m_V; V_W = 135 m_V with right side of pilot at high voltage

D

V_B = 40 m_V; V_W = 135 m_V with left side of pilot at higher voltage

Question 54: Palette 54/66

JEE Mains 2016 MCQ

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 :

A

$A$ for transformers and $B$ for electric generators.

B

$B$ for electromagnets and transformers.

C

$A$ for electric generators and transformers.

D

$A$ for electromagnets and $B$ for electric generators.

Question 55: Palette 55/66

JEE Mains 2014 MCQ

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 B_s inside the superconductor will be such that :

A

B_s = $-$ B

B

B_s = 0

C

B_s = B

D

B_s < B  but  B_s $ \ne $ 0

Question 56: Palette 56/66

JEE Mains 2014 MCQ

The coercivity of a small magnet where the ferromagnet gets demagnetized is $3 \times {10^3}\,A{m^{ - 1}}.$ 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 :

A

$30$ $mA$

B

$60$ $mA$

C

$3$ $A$

D

$6A$

Question 57: Palette 57/66

JEE Mains 2013 MCQ

Two short bar magnets of length $1$ $cm$ each have magnetic moments $1.20$ $A{m^2}$ and $1.00$ $A{m^2}$ 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 $20.0$ $cm.$ The value of the resultant horizontal magnetic induction at the mid-point $O$ of the line joining their centres is close to $\left( \, \right.$ Horizontal component of earth's magnetic induction is $3.6 \times 10.5Wb/{m^2})$

A

$3.6 \times 10.5\,\,Wb/{m^2}$

B

$2.56 \times 10.4\,\,Wb/{m^2}$

C

$3.50 \times 10.4\,\,Wb/{m^2}$

D

$5.80 \times 10.4\,Wb/{m^2}$

Question 58: Palette 58/66

JEE Mains 2008 MCQ

Relative permittivity and permeability of a material ${\varepsilon _r}$ and ${\mu _r},$ respectively. Which of the following values of these quantities are allowed for a diamagnetic material?

A

${\varepsilon _r} = 0.5,\,\,{\mu _r} = 1.5$

B

${\varepsilon _r} = 1.5,\,\,{\mu _r} = 0.5$

C

${\varepsilon _r} = 0.5,\,\,{\mu _r} = 0.5$

D

${\varepsilon _r} = 1.5,\,\,{\mu _r} = 1.5$

Question 59: Palette 59/66

JEE Mains 2006 MCQ

Needles ${N_1}$, ${N_2}$ and ${N_3}$ are made of ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will

A

attract ${N_1}$ and ${N_2}$ strongly but repel ${N_3}$

B

attract ${N_1}$ strongly, ${N_2}$ weakly and repel ${N_3}$ weakly

C

attract ${N_1}$ strongly, but repel ${N_2}$ and ${N_3}$ weakly

D

attract all three of them

Question 60: Palette 60/66

JEE Mains 2005 MCQ

A magnetic needle is kept in a non-uniform magnetic field. It experiences :

A

neither a force nor a torque

B

a torque but not a force

C

a force but not a torque

D

a force and a torque

Question 61: Palette 61/66

JEE Mains 2004 MCQ

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

A

$2\sqrt 3 \,s$

B

${2 \over 3}\,\,s$

C

$2\,s$

D

${2 \over {\sqrt 3 }}\,s$

Question 62: Palette 62/66

JEE Mains 2004 MCQ

Curie temperature is the temperature above which

A

a ferromagnetic material becomes paramagnetic

B

a paramagnetic material becomes diamagnetic

C

a ferromagnetic material becomes diamagnetic

D

a paramagnetic material becomes ferromagnetic

Question 63: Palette 63/66

JEE Mains 2004 MCQ

The materials suitable for making electromagnets should have

A

high retentivity and low coercivity

B

low retentivity and low coercivity

C

high retentivity and high coercivity

D

low retentivity and high coercivity

Question 64: Palette 64/66

JEE Mains 2003 MCQ

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 ${{T'} \over T}$ is

A

${1 \over {2\sqrt 2 }}$

B

${1 \over 2}$

C

$2$

D

${1 \over 4}$

Question 65: Palette 65/66

JEE Mains 2003 MCQ

A magnetic needle lying parallel to a magnetic field requires $W$ units of work to turn it through ${60^ \circ }.$ The torque needed to maintain the needle in this position will be :

A

$\sqrt 3 \,W$

B

$W$

C

${{\sqrt 3 } \over 2}W$

D

$2W$

Question 66: Palette 66/66

JEE Mains 2003 MCQ

The magnetic lines of force inside a bar magnet

A

are from north-pole to south-pole of the magnet

B

do not exist

C

depend upon the area of cross-section of the bar magnet

D

are from south-pole to north-pole of the Magnet