1
JEE Main 2026 (Online) 23rd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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)

2
JEE Main 2025 (Online) 7th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
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)

3
JEE Main 2025 (Online) 7th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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
$\frac{6}{5} \times 10^{-3} \%$
4
JEE Main 2025 (Online) 3rd April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
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

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