1
JEE Main 2026 (Online) 5th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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) 5th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Under steady state condition the potential difference across the capacitor in the circuit is $\_\_\_\_$ V.

JEE Main 2026 (Online) 5th April Evening Shift Physics - Capacitor Question 2 English
A

0.5

B

1.5

C

0

D

2

3
JEE Main 2026 (Online) 5th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A particle of charge $q$ and mass $m$ is projected from origin with an initial velocity $\vec{v}=\left(\frac{v_0}{\sqrt{2}} \hat{x}+\frac{v_0}{\sqrt{2}} \hat{y}\right)$. There exists a uniform magnetic field $\vec{B}=B_0 \hat{z}$ and a space varying electric field $\vec{E}=E_{\mathrm{o}} \mathrm{e}^{-\lambda x} \hat{x}$ within the region $0 \leqslant x \leqslant L$. After travelling a distance such that $x$-coordinate has changed from $x=0$ to $x=L$, the change in the kinetic energy is $\_\_\_\_$ .

A

$\frac{q E_0}{\lambda}\left[1-e^{-\lambda L}\right]$

B

$\left(\frac{v_0 q B_0}{2 \lambda}\right)\left[2-e^{-2 \lambda L}\right]$

C

$$ \frac{q E_0}{\lambda}\left[1+e^{-\lambda L}\right] $$

D

$$ q\left(\frac{E_0+v_0 B_0}{\lambda}\right)\left[1-e^{-\lambda L / 2}\right] $$

4
JEE Main 2026 (Online) 5th 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) : The electromagnetic wave exerts pressure on the surface on which they are allowed to fall.

Reason (R) : There is no mass associated with the electromagnetic waves.

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

A

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

B

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

C

(A) is true but (R) is false

D

(A) is false but (R) is true

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