Magnetism and Matter

The relationship between the magnetic susceptibility \((\chi )\) and the magnetic permeability \((\mu )\) is given by :
( \({\mu }_{0}\) is the permeability of free space and \({\mu }_{\mathrm{r}}\) is relative permeability)

[JEE Main 2025, 2 Apr (Shift 1)]

The source of time varying magnetic field may be
A. a permanent magnet
B. an electric field changing linearly with time

C. direct current

D. a decelerating charge particle
E. an antenna fed with a digital signal

Choose the correct answer from the options given below:

[JEE Main 2023, 13 Apr (Shift 1)]

The relationship between the magnetic susceptibility \((\chi )\) and the magnetic permeability \((\mu )\) is given by :
( \({\mu }_{0}\) is the permeability of free space and \({\mu }_{\mathrm{r}}\) is relative permeability)

[JEE Main 2025, 2 Apr (Shift 1)]

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 :

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, 7 Apr (Shift 2)]

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, 3 Apr (Shift 2)]

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, 7 Apr (Shift 1)]

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:

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

[JEE Main 2023, 11 Apr (Shift 1)]

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:

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 answer from the options given below.

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.

[JEE Main 2023, 10 Apr (Shift 2)]

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

[JEE Main 2021, 20 Jul (Shift 2)]

A bar magnet with a magnetic moment 5.0 Am² is placed in parallel position relative to a magnetic field of 0.4 T. The amount of work done required in turning the magnet from parallel to antiparallel position relative to the field direction is _______.