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

Consider a square $A B C D$ of diagonal length 2a. The square is folded along the diagonal $A C$ so that the plane of $\triangle A B C$ is perpendicular to the plane of $\triangle A D C$. In this case the shortest distance between $A B$ and $C D$ is

A

$\frac{2 a}{\sqrt{3}}$

B

$\frac{a}{2 \sqrt{3}}$

C

$\frac{\mathrm{a}}{\sqrt{3}}$

D

$\frac{\sqrt{3} a}{2}$

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

If $\int \frac{\left(1-x^2\right)}{\sqrt{x} \sqrt{\left(1+x^2\right)^3}}=\alpha \frac{x^\beta}{\left(1+x^2\right)^\gamma}+C ; \alpha, \beta, \gamma \in \mathbb{R}$ and $C$ is constant of integration, then $\alpha: \beta: \gamma$ will be

A

$4: 1: 1$

B

$2: 2: \frac{1}{2}$

C

$\frac{1}{6}: 2: \frac{1}{2}$

D

$1: 2: \frac{1}{2}$

3
WB JEE 2026
MCQ (Single Correct Answer)
+2
-0.5
Change Language

Let $\vec{a}=(x, y, z)$ be the vector with $|\vec{a}|=2 \sqrt{3}$, which makes equal angles with the vector $\vec{b}=(y,-2 z, 3 x)$ and $\vec{c}=(2 z, 3 x,-y)$ and is perpendicular to the vector $\vec{d}=(1,-1,2)$. If the angle between $\vec{a}$ and the unit vector $\hat{j}$ is obtuse, then $\vec{a}$ is

A

$(2,-2,-2)$

B

$(-2,-2,2)$

C

$(-2,2,-2)$

D

$(2,-2,2)$

4
WB JEE 2026
MCQ (Single Correct Answer)
+2
-0.5
Change Language

Let $A_1, A_2, \ldots, A_6$ are six sets, each with four elements and $B_1, B_2, \ldots ., B_n$ are $n$ sets, each with two elements. Let $S=A_1 \cup A_2 \cup \ldots \cup A_6=B_1 \cup B_2 \cup \ldots \cup B_n$.

Given that each element of $S$ belongs to exactly four of the A's and to exactly three of the B's. Then $n$ is

A

12

B

24

C

6

D

9