MCQ
If $a$ is non zero vector of modulus   $ a $ and $m$  is a non-zero scalar, then $ma$ is a unit vector if
  • A
    $m = \pm 1$
  • B
    $m = \,\,|a|$
  • $m = \frac{1}{{|a|}}$
  • D
    $m = \pm \,2$

Answer

Correct option: C.
$m = \frac{1}{{|a|}}$
c
(c) $ma $ is a unit vector if and only if $|m\,a|$ ==> $m$

$⇒$ $m = \frac{1}{{|a|}}$.

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