Does this actuallly have an answer?

Hi Elijah    

The parabola needs to be of the form  x^2=4ay   [The vertex is (0,0)]

a is the foacl length

$x^2 =4ay=\frac{8}{5}y=4*\frac{2}{5}y$  

the foacal length is 2/5 = 0.4"

So the bulb must be placed 0.4 inches from the vertex.