JEE Main 2026 (Online) 5th April Evening Shift | Electromagnetic Induction Question 4 | Physics

1

JEE Main 2026 (Online) 5th April Evening Shift

MCQ (Single Correct Answer)

+4

-1

A metal rod of length $L$ rotates about one end at origin with a uniform angular velocity $\omega$. The magnetic field radially falls off as $B(\mathrm{r})=B_{\mathrm{o}} \mathrm{e}^{-\lambda r} ; \lambda$ being a positive constant. The emf induced (neglecting the centripetal force on electrons in the rod) is :

A

$$ B_o \omega\left[\frac{1}{\lambda^2}-e^{-\lambda L}\left(\frac{1}{\lambda^2}+\frac{L}{\lambda}\right)\right] $$

B

$$ B_o \omega\left[\frac{1}{\lambda^2}+e^{-\lambda L}\left(\frac{1}{\lambda^2}+\frac{L}{\lambda}\right)\right] $$

C

$$ B_o \omega\left[\frac{4}{\lambda^2}-e^{-2 \lambda L}\left(\frac{1}{\lambda^2}+\frac{2 L}{\lambda}\right)\right] $$

D

$$ B_0 \omega\left[\frac{3}{\lambda^2}-e^{-3 \lambda L}\left(\frac{3}{\lambda^2}+\frac{L}{\lambda}\right)\right] $$

2

JEE Main 2026 (Online) 2nd April Evening Shift

MCQ (Single Correct Answer)

+4

-1

A circular current loop of radius $R$ is placed inside square loop of side length $L$ ($L \gg R$) such that they are co-planar and their centers coincide. The permeability of free space is $\mu_0$. The mutual inductance between circular loop and square loop is ______.

A

$2\sqrt{2}\dfrac{\mu_0 L^2}{R}$

B

$\sqrt{2}\dfrac{\mu_0 L^2}{R}$

C

$\sqrt{2}\dfrac{\mu_0 R^2}{L}$

D

$2\sqrt{2}\dfrac{\mu_0 R^2}{L}$

3

JEE Main 2026 (Online) 2nd April Morning Shift

MCQ (Single Correct Answer)

+4

-1

When a coil is placed in a time dependent magnetic field the power dissipated in it is $P$. The number of turns, area of the coil and radius of the coil wire are $N$, $A$ and $r$ respectively. For a second coil number of turns, area of the coil and radius of the coil wire are $2N$, $2A$ and $3r$ respectively. When the first coil is replaced with second coil the power dissipated in it is $\sqrt{2} \,\alpha P$. The value of $\alpha$ is ______.

A

36

B

128 $ \sqrt{2} $

C

16

D

64

4

JEE Main 2026 (Online) 24th January Morning Shift

MCQ (Single Correct Answer)

+4

-1

$$ \text { Match the LIST-I with LIST-II } $$

List-I		List-II
A.	Magnetic induction	I.
B.	Magnetic flux	II.
C.	Magnetic permeability	III.
D.	Self inductance	IV.

Choose the correct answer from the options given below:

A

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

B

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

C

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

D

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

JEE Main Subjects