Question

A vector is represented by $3\hat{i}+\hat{j}+2\hat{k}$. Its length in $X-Y$ plane is

• A. $2$
• B. $\sqrt{14}$
• C. $\sqrt{10}$
• D. $\sqrt{5}$

Answer 1

Answer: (A), (C)

$\sqrt{10}$

Explanation for correct option:

Given vector $3\hat{i}+\hat{j}+2\hat{k}$

We know that the length of a vector from $x-y\mathrm{plane}$ is $\sqrt{{\left(x\right)}^2+{\left(y\right)}^2}$

$=\sqrt{{\left(3\right)}^2+{\left(1\right)}^2}$

$=\sqrt{10}$

Hence, option $\left(C\right)$ is correct .