A vector is represented by 3 î + ĵ + 2 k̂.

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A vector is represented by $3\,\hat i + \hat j + 2\,\hat k$. Its length in $XY$ plane is

A

$2$

B

$\sqrt {14} $

C

$\sqrt {10} $

D

$\sqrt 5 $
A vector is represented by $3\,\hat i + \hat j + 2\,\hat k$. Its length in $XY$ plane is
$\vec R = 3\hat i + \hat j + 2\hat k$
Length in $XY$ plane = $\sqrt {R_x^2 + R_y^2} = \sqrt {{3^2} + {1^2}} $$ = \sqrt {10} $