Q. The equation of the mirror that can reflect all incident rays from origin parallel to $y$-axis is
A) $x^{2} = 4a(y + a)$
B) $y^{2} = 4a(x + a)$
C) $y^{2} = - 4a(x - a)$
D) None of these
Explanation
(a)
The equation of such mirror is an equation of the parabola whose axis is $y$-axis and whose focus is $(0,\ 0)$
[image:11_image45.emf]
$\therefore$ Required equation is $x^{2} = 4a(y + a)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.