JEE Main 2025 (Online) 7th April Evening Shift

MCQ (Single Correct Answer)

-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:

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

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

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

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

JEE Main 2025 (Online) 7th April Morning Shift

MCQ (Single Correct Answer)

-1

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 :

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

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

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

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

JEE Main 2025 (Online) 3rd April Evening Shift

MCQ (Single Correct Answer)

-1

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 :

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

-80 J

80 J

-60 J

JEE Main 2025 (Online) 2nd April Morning Shift

MCQ (Single Correct Answer)

-1

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)

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

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

$\chi=\mu_r+1$

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

JEE Main Subjects