Question

The direction cosines of any normal to the $xy-$ plane are

• A. 1, 0, 0
• B. 0, 1, 0
• C. 1, 1, 0
• D. 0, 0, 1

Answer 1

Answer: (D)

The equation of $xy-$ plane is $z=0$
$\therefore$ Direction cosines of its normal are $0,0,1.$