Question

A vector is represented by $3\widehat{i} + \widehat{j} + 2\widehat{k}$. Its length in XY plane is

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

Answer 1

Answer: (C)

$\sqrt{10}$

Answer 2

$\overrightarrow{R} = 3\widehat{i} + \widehat{j} + 2\widehat{k}$

∴ Length in XY plane

= $\sqrt{R_{x}^{2} + R_{y}^{2}} = \sqrt{3^{2} + 1^{2}} = \sqrt{10}$