MCQ
The unit vector perpendicular to both $i + j$ and $j + k$ is
  • A
    $i -j + k$
  • B
    $i + j + k$
  • C
    $\frac{{i + j - k}}{{\sqrt 3 }}$
  • $\frac{{i - j + k}}{{\sqrt 3 }}$

Answer

Correct option: D.
$\frac{{i - j + k}}{{\sqrt 3 }}$
d
(d) Unit vector perpendicular to both

$ = \frac{{(i + j) \times (j + k)}}{{|(i + j) \times (j + k)|}} = \frac{{i - j + k}}{{\sqrt 3 }}$.

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