Question

The direction cosines of the normal to the plane 2x + 3y - 6z = 5 are

• A.
  
• B.
  
• C.
  
• D. None of these

Answer 1

The correct option is B

Direction ratios of normal to the plane are (2, 3, - 6)
$\therefore$ Direction cosines are, $(\frac{2}{\sqrt{49}},\frac{3}{\sqrt{49}},-\frac{6}{\sqrt{49}})$ or
$(\frac{2}{7},\frac{3}{7},\frac{-6}{7})$.