Q. The equation of the parabola with vertex at the origin and directrix $y = 2$ is
A) $y^{2} = 8x$
B) $y^{2} = - 8x$
C) $y^{2} = \sqrt{8}x$
D) $x^{2} = - 8y$
Explanation
(d)
Directrix of parabola is $y = 2\$
$\Rightarrow \ a = - 2\$
$\therefore\$Required equation of parabola is
$x^{2} = - 4.2.y\ \Rightarrow \ \ x^{2} = - 8y$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.