Question

The unit vector(s) parallel to $\overline{i}-3\overline{j}-5\overline{k}$ is

• A. $+\frac{1}{\sqrt{35}}(\overline{i}-3\overline{j}-5\overline{k})$
• B. $\overline{i}-3\overline{j}-5\overline{k}$
• C. $-\frac{1}{\sqrt{35}}(\overline{i}-3\overline{j}-5\overline{k})$
• D. Both $A$ and $C$

Answer 1

The correct option is D Both $A$ and $C$

We have,
$\overrightarrow{PQ}=\overrightarrow{i}-3\overrightarrow{j}-5\overrightarrow{k}$

$\overrightarrow{PQ}=\sqrt{35}$

$\pm \frac{1}{\sqrt{35}}\left(\overrightarrow{i}-3\overrightarrow{j}-5\overrightarrow{k}\right)$

Then,

Option $D$ is correct answer.