A) 0
B) 1
C) \[-2\]
D) \[-3\]
Correct Answer: C
Solution :
Key Idea: If a and b are two perpendicular vectors, then their dot product will be zero. Let\[\vec{a}=2\hat{i}+\hat{j}-\hat{k}\]and \[\vec{b}=\hat{i}-4\hat{j}+\lambda \hat{k}.\] Since, \[\vec{a}\]and \[\vec{b}\]are perpendicular \[\therefore \] \[\vec{a}.\vec{b}=(2\hat{i}+\hat{j}-\hat{k}).(\hat{i}-4\hat{j}+\lambda \hat{k})=0\] \[\Rightarrow \] \[2-4-\lambda =0\] \[\Rightarrow \] \[\lambda =-2\]You need to login to perform this action.
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