Question

Consider a vector $F=4\hat{i}-3\hat{j}$. Another vector which is perpendicular to $\overrightarrow{F}$ is:

• A. $4\hat{i}+3\hat{j}$
• B. $6\hat{i}$
• C. $7\hat{k}$
• D. $3\hat{i}-4\hat{j}$

Answer 1

The correct option is C $7\hat{k}$

The vector perpendicular to the $i$ & $j$ plane would be along the unit vector $k$.
Another vector in $i$ & $j$ plane can be perpendicular to $\overrightarrow{F}$
$(3\hat{i}+4\hat{j})\perp (4\hat{i}-3\hat{j})$
But, from the options only $7\hat{k}\perp (4\hat{i}-3\hat{j})$