2. Solved Papers
  3. CEE Kerala Engineering

CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2006

  • question_answer
    If the two vectors\[\overrightarrow{A}=2\hat{i}+3\hat{j}+4\hat{k}\]and\[\overrightarrow{B}=\hat{i}+2\hat{j}-n\hat{k}\]are perpendicular then the value of n is:

    A)  1                            

    B)         2

    C)  3                            

    D)         4

    E)  5

    Correct Answer: B

    Solution :

    The scalar product of two vectors is \[\overrightarrow{A}.\overrightarrow{B}=AB\cos \theta \] When \[\theta =90{}^\circ ,\]then \[\cos 90{}^\circ =0\]                 \[\overrightarrow{A}.\overrightarrow{B}=0\] \[(2\hat{i}+3\hat{j}+4\hat{k}).(\hat{i}+2\hat{j}-n\hat{k})=0\] \[\Rightarrow \]               \[2+6-4n=0\] \[\Rightarrow \]               \[n=\frac{8}{4}=2\]


You need to login to perform this action.
You will be redirected in 3 sec spinner