Question

the reflector of a flashlight is in the shape of parabolic surface. The the reflections of all rays from the light bulb to any point on the parabolic surface will be all parallel to each other. The casting has a diameter of 16 cm and a depth of 8 cm. Find the the focus to determine how far the light bulb should be placed from the vertex.the light bulb should be placed ? centimeters (s) from the vertex

Answer 1

We will solve using the formula:

$f=\frac{x^2}{4a}$

Where x is the radious of the shape, and a is the depth of the shape, knowing this, we replace:

$f=\frac{8^2}{4(8)}\Rightarrow f=2$

From this, we have that the focus is found 2 cm from the vertex.