1
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

There is a ring of radius $r$ having linear charge density $\lambda$ and rotating with a uniform angular velocity $\omega$. The magnitude of the magnetic field produced by this ring at its own centre would be ( $\mu_0=$ permeability of air)

A

$\frac{\lambda \omega^2}{2-\mu_0}$

B

$\frac{\mu_0 \lambda^2 \omega}{\sqrt{2}}$

C

$\frac{\mu_0 \lambda \omega}{2}$

D

$\frac{\mu_0 \lambda}{2 \omega^2}$

2
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Three vectors $\vec{a}, \vec{b}$ and $\vec{c}$ are such that $|\vec{a}|=1,|\vec{b}|=2$ and $|\vec{c}|=4$ along with $\vec{a}+\vec{b}+\vec{c}=0$ .Then,the value of $4 \vec{a} \cdot \vec{b}+3 \vec{b} \cdot \vec{c}+3 \vec{c} \cdot \vec{a}$ will be

A

27

B

-26

C

-68 problem is wrong.

D

-34

3
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Two identical metal bars are heated in two different temperatures and allowed to cool in the same surroundings. Which one of the following figures correctly shows their cooling curves?

A

WB JEE 2026 Physics - Heat and Thermodynamics Question 1 English Option 1

B

WB JEE 2026 Physics - Heat and Thermodynamics Question 1 English Option 2

C

WB JEE 2026 Physics - Heat and Thermodynamics Question 1 English Option 3

D

WB JEE 2026 Physics - Heat and Thermodynamics Question 1 English Option 4

4
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

The inputs to a digital circuit are as shown below. The output Y is

WB JEE 2026 Physics - Electronic Devices Question 3 English

A

$A+B+\bar{C}$

B

$(A+B) \bar{C}$

C

$\bar{A}+\bar{B}+\bar{C}$

D

$\bar{A}+\bar{B}+C$