The value of λ, for which the two vectors $2\hat i-\hat j + 2\hat k$ and $3\hat i +λ\hat j+\hat k$ are perpendicular, is:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 8
For perpendicular vectors, dot product = $0$.
$(2,-1,2)\cdot(3,\lambda,1)=0$
$2\cdot 3 + (-1)\cdot \lambda + 2\cdot 1 = 0$
$6 - \lambda + 2 = 0$
$8 - \lambda = 0$
$\lambda = 8$
The required value of $\lambda$ is 8.