JEE Main & Advanced AIEEE Solved Paper-2007

  • question_answer
    Let\[67.2\text{ }L\,{{H}_{2}}(g)\]. If\[Al\]then | a| equals       AIEEE  Solved  Paper-2007

    A)  \[11.2\,L\,{{H}_{2}}(g)\]                  

    B)         1                            

    C)  \[HCl(aq)\]   

    D)  5

    Correct Answer: C

    Solution :

                    Firstly, solve\[{{A}^{2}}=A.\text{ }A\]and then \[|{{A}^{2}}|=25.\] \[\because \] \[A=\left[ \begin{matrix}    5 & 5\alpha  & \alpha   \\    0 & \alpha  & 5\alpha   \\    0 & 0 & 5  \\ \end{matrix} \right]\] \[\therefore \] \[{{A}^{2}}=\left[ \begin{matrix}    5 & 5\alpha  & \alpha   \\    0 & \alpha  & 5\alpha   \\    0 & 0 & 5  \\ \end{matrix} \right]\left[ \begin{matrix}    5 & 5\alpha  & \alpha   \\    0 & \alpha  & 5\alpha   \\    0 & 0 & 5  \\ \end{matrix} \right]\] \[=\left[ \begin{matrix}    25 & 25\alpha +5{{\alpha }^{2}} & 10\alpha +25{{\alpha }^{2}}  \\    0 & {{\alpha }^{2}} & 5{{\alpha }^{2}}+25\alpha   \\    0 & 0 & 25  \\ \end{matrix} \right]\] \[=25\left| \begin{matrix}    25 & 25\alpha +5{{\alpha }^{2}}  \\    0 & {{\alpha }^{2}}  \\ \end{matrix} \right|=625{{\alpha }^{2}}\] But \[|{{A}^{2}}|=25\] \[\therefore \]\[625{{\alpha }^{2}}=25\Rightarrow |\alpha |=\frac{1}{5}\]


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