Question

Subject: Light and Geometric Optics

Question: Where must a light source be placed in front of a concave mirror for
a) light energy to be concentrated to a single point
b)the light to be reflected in a parallel beam?

Answer 1

a) Anywhere beyond the focal point will do. If you want the light concentrated at the same location as the source, the distance must be 2f.

b) At the focal point

Answer 2

Thank you!