# If $\overrightarrow{a},\overrightarrow{b},\overrightarrow{c}$ are a right handed triad of mutually perpendicular vectors of magnitude $a, b , c$ than value of $[\overrightarrow{a} \overrightarrow{b} \overrightarrow{c}]$ is

$\begin{array}{1 1}(1) a^{2} b^{2} c^{2} &(2)0\\(3)\frac{1}{2} abc&(4)abc \end{array}$

Given $\overrightarrow{a},\overrightarrow{b},\overrightarrow{c}$ are mutually perpendicular vectors of magnitude a,b,c then
$[\overrightarrow{a} \overrightarrow{b} \overrightarrow{c}] =abc$
Hence 4 is the correct answer.