A unit vector which is perpendicular to i + 2j - 2k and - i + 2j … - Vidyadip

MCQ

A unit vector which is perpendicular to $i + 2j - 2k$ and $ - i + 2j + 2k$ is

A
$\frac{1}{{\sqrt 5 }}\,(2i - k)$
B
$\frac{1}{{\sqrt 5 }}\,( - 2i + k)$
C
$\frac{1}{{\sqrt 5 }}\,(2i + j + k)$
✓
$\frac{1}{{\sqrt 5 }}\,(2i + k)$

✓

Answer

Correct option: D.

$\frac{1}{{\sqrt 5 }}\,(2i + k)$

d
(d) Unit vector is equal to $\frac{{a \times b}}{{|a \times b|}} = \frac{1}{{\sqrt 5 }}(2i + k).$

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