Vector Algebra Question 9
Question: If $4 \hat{i}+\hat{j}-\hat{k}$ and $3 \hat{i}+m \hat{j}+2 \hat{k}$ are at right angle, then $m=$
[Karnataka CET 2002]
Options:
A) - 6
B) - 8
C) - 10
D) - 12
Show Answer
Answer:
Correct Answer: C
Solution:
- Since angle between the vectors is $ 90^{o} $ , therefore dot product of the vectors will be zero or $ (4\mathbf{i}+\mathbf{j}-\mathbf{k}),.,(3\mathbf{i}+m\mathbf{j}+2\mathbf{k})=0 $ or $ 12+m-2=0 $ or $ m=-10. $
BETA
