Answer:
8/9 cm above the Vertex
Step-by-step explanation:
Given that:
Diameter of mirror = 8cm
Depth = 4.5 cm
Assume parabola opens up to the right, then p is positive
y² = 4px
Point on the parabola will then be ;
(Depth, d/2) = (4.5, 4)
x = 4.5 ; y = 4
4² = 4p(4.5)
16 = 18p
p = 16/18
p = 8/9
Hence, bulb should be placed 8/9 cm above the Vertex