1
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

$(2,-2,2)$

2
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

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

A figure is bounded by the curves $y=x^2+1, y=0, x=0$ and $x=1$. The point at which a tangent should be drawn to the curve $y=x^2+1$ for it to cut off trapezium of the greatest area from the figure is

A

$(1,2)$

B

$(-1,2)$

C

$\left(\frac{1}{2}, \frac{5}{4}\right)$

D

$(0,1)$

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

The ends $A$, $B$ of a straight line segment of constant length $c$ slide upon the fixed rectangular axes $O X, O Y$ respectively. If the rectangle $O A P B$ completed, then the locus of the foot of perpendicular drawn from $P$ to $A B$ is

A

$x^2+y^2=c^2$

B

$\mathrm{x}^{2 / 3}+\mathrm{y}^{2 / 3}=\mathrm{c}^{2 / 3}$

C

$\sqrt{x}+\sqrt{y}=\sqrt{c}$

D

$x y=c^2$