All the rays emanating from origin becomes parallel to y-axis after being reflected from the surface of a mirror, then equation of such a mirror may be

Question

All the rays emanating from origin becomes parallel to y-axis after being reflected from the surface of a mirror, then equation of such a mirror may be (A) x2=4 a(y+a) (B) x2=-4 a(y+a) (C) x 2=4 a ( y - a ) (D)  x2=-4 a(y-a)

Tardigrade Admin · Accepted Answer

Clearly origin should be focus and y-axis should be axis of parabola for reflected rays to the parallel to y-axis.

Q. All the rays emanating from origin becomes parallel to $y$ -axis after being reflected from the surface of a mirror, then equation of such a mirror may be

$x^{2} = 4 a (y + a)$

$x^{2} = - 4 a (y + a)$

$x^{2} = 4 a (y - a)$

$x^{2} = - 4 a (y - a)$

Clearly origin should be focus and y-axis should be axis of parabola for reflected rays to the parallel to y-axis.

Q. All the rays emanating from origin becomes parallel to y-axis after being reflected from the surface of a mirror, then equation of such a mirror may be

x2=4a(y+a)

x2=−4a(y+a)

x2=4a(y−a)

x2=−4a(y−a)

Clearly origin should be focus and y-axis should be axis of parabola for reflected rays to the parallel to y-axis.

Q. All the rays emanating from origin becomes parallel to $y$ -axis after being reflected from the surface of a mirror, then equation of such a mirror may be

$x^{2} = 4 a (y + a)$

$x^{2} = - 4 a (y + a)$

$x^{2} = 4 a (y - a)$

$x^{2} = - 4 a (y - a)$