1
JEE Main 2025 (Online) 8th April Evening Shift
MCQ (Single Correct Answer)
+4
-1

Figure shows a current carrying square loop ABCD of edge length is ‘a’ lying in a plane. If the resistance of the ABC part is r and that of ADC part is 2r, then the magnitude of the resultant magnetic field at centre of the square loop is

JEE Main 2025 (Online) 8th April Evening Shift Physics - Magnetic Effect of Current Question 10 English
A

$\frac{2\mu_0 I}{3\pi a}$

B

$\frac{\sqrt{2}\mu_0 I}{3\pi a}$

C

$\frac{3\pi\mu_0 I}{\sqrt{2}a}$

D

$\frac{\mu_0 I}{2\pi a}$

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

A particle of charge $q$, mass $m$ and kinetic energy $E$ enters in magnetic field perpendicular to its velocity and undergoes a circular arc of radius (r). Which of the following curves represents the variation of $r$ with $E$ ?

A
JEE Main 2025 (Online) 7th April Morning Shift Physics - Magnetic Effect of Current Question 6 English Option 1
B
JEE Main 2025 (Online) 7th April Morning Shift Physics - Magnetic Effect of Current Question 6 English Option 2
C
JEE Main 2025 (Online) 7th April Morning Shift Physics - Magnetic Effect of Current Question 6 English Option 3
D
JEE Main 2025 (Online) 7th April Morning Shift Physics - Magnetic Effect of Current Question 6 English Option 4
3
JEE Main 2025 (Online) 7th April Morning Shift
MCQ (Single Correct Answer)
+4
-1

Uniform magnetic fields of different strengths $\left(B_1\right.$ and $\left.B_2\right)$, both normal to the plane of the paper exist as shown in the figure. A charged particle of mass $m$ and charge $q$, at the interface at an instant, moves into the region 2 with velocity $v$ and returns to the interface. It continues to move into region 1 and finally reaches the interface. What is the displacement of the particle during this movement along the interface?

JEE Main 2025 (Online) 7th April Morning Shift Physics - Magnetic Effect of Current Question 5 English

(Consider the velocity of the particle to be normal to the magnetic field and $\mathrm{B}_2>\mathrm{B}_1$ )

A
$\frac{m v}{q B_1}\left(1-\frac{B_1}{B_2}\right) \times 2$
B
$\frac{m v}{q B_1}\left(1-\frac{B_2}{B_1}\right) \times 2$
C
$\frac{m v}{q B_1}\left(1-\frac{B_2}{B_1}\right)$
D
$\frac{m v}{q B_1}\left(1-\frac{B_1}{B_2}\right)$
4
JEE Main 2025 (Online) 3rd April Evening Shift
MCQ (Single Correct Answer)
+4
-1

Given below are two statements: one is labelled as $\mathbf{A s s e r t i o n} \mathbf{A}$ and the other is labelled as Reason $\mathbf{R}$

Assertion A : If Oxygen ion $\left(\mathrm{O}^{-2}\right)$ and Hydrogen ion $\left(\mathrm{H}^{+}\right)$enter normal to the magnetic field with equal momentum, then the path of $\mathrm{O}^{-2}$ ion has a smaller curvature than that of $\mathrm{H}^{+}$.

Reason R : A proton with same linear momentum as an electron will form a path of smaller radius of curvature on entering a uniform magnetic field perpendicularly.

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

A
Both $\mathbf{A}$ and $\mathbf{R}$ are true but $\mathbf{R}$ is NOT the correct explanation of $\mathbf{A}$
B
$\mathbf{A}$ is false but $\mathbf{R}$ is true
C
$\mathbf{A}$ is true but $\mathbf{R}$ is false
D
Both $\mathbf{A}$ and $\mathbf{R}$ are true and $\mathbf{R}$ is the correct explanation of $\mathbf{A}$
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