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

Let us define the power of a matrix $A$ as the maximum $m \in Z^{+}$such that $A^m=I$. For two matrices $A$ and $B$ if $A^5=I$ and $A B A^{-1}=B^2$, then the power of the matrix $B$ is between

A

20 and 24

B

28 and 32

C

36 and 40

D

4 and 8

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

Let $\operatorname{det} A=\left|\begin{array}{ccc}\mathrm{l} & \mathrm{m} & \mathrm{n} \\ \mathrm{p} & \mathrm{q} & \mathrm{r} \\ \mathrm{l} & \mathrm{l} & \mathrm{l}\end{array}\right|$ If $(I-m)^2+(p-q)^2=9,(m-n)^2+(q-r)^2=16,(n-I)^2+(r-p)^2=25$, then the value of $(\operatorname{det} A)^2$ is

A

169

B

144

C

121

D

100

3
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

If the matrix $\left(\begin{array}{ccc}0 & a & a \\ 2 b & b & -b \\ c & -c & c\end{array}\right)$ is orthogonal, then the values of $a, b, c$ are

A
$a= \pm \frac{1}{\sqrt{3}}, b= \pm \frac{1}{\sqrt{6}}, c= \pm \frac{1}{\sqrt{2}}$
B
$a= \pm \frac{1}{\sqrt{2}}, b= \pm \frac{1}{\sqrt{6}}, c= \pm \frac{1}{\sqrt{3}}$
C
$a=-\frac{1}{\sqrt{2}}, b=-\frac{1}{\sqrt{6}}, c=-\frac{1}{\sqrt{3}}$
D
$a=\frac{1}{\sqrt{3}}, b=\frac{1}{\sqrt{6}}, c=\frac{1}{\sqrt{3}}$
4
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Let $A=\left[\begin{array}{ccc}5 & 5 \alpha & \alpha \\ 0 & \alpha & 5 \alpha \\ 0 & 0 & 5\end{array}\right]$. If $|A|^2=25$, then $|\alpha|$ equals to

A
5$^2$
B
1
C
$\frac{1}{5}$
D
5

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