Question

If a unit vector is represented by $0.5\hat{i}-0.8\hat{j}+c\hat{k}$ then the value of c is

• A. $\sqrt{0.01}$
• B. $\sqrt{0.11}$
• C. $1$
• D. $\sqrt{0.39}$

Answer 1

Answer: (B)

For a unit vector $\hat{n}$, $|\hat{n}|=1$
$|0.5\hat{i}-0.8\hat{j}+c\hat{k}{|}^2=1^2$
$\Rightarrow 0.25+0.64+c^2=1$
or c = $\sqrt{0.11}$