Question

If a vector $2\hat{i}+3\hat{j}+8\hat{k}$ is perpendicular to the vector $4\hat{j}-4\hat{i}+\alpha \hat{k}.$ Then, the value of $\alpha$ is :

• A. $\frac{-1}{2}$
• B. $-1$
• C. $\frac{1}{2}$
• D. $1$

Answer 1

The correct option is C $\frac{1}{2}$

Do dot product of these two vectors should be equal to zero as they are perpendicular to each other.

$\therefore A.B=8-12+8\alpha =0.$

$8\alpha =4$

$\alpha =\frac{1}{2}$