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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