Question

You want to build a search light. The search light is to have an outgoing parallel beam. You have a small, very bright light (a point light source) and a concave mirror with radius of curvature 2m. How far from the mirror should the point light source be placed so the mirror produces an outgoing parallel beam

Answer 1

Answer:

1 m                              

Explanation:

Given

The mirror is a concave mirror.

Radius of curvature = 2 m

Now, for a parallel beam after reflection  occurs, the object should be placed at the focus of the mirror.

We know, focal length = radius of curvature / 2

                                      = 2 / 2

                                      = 1

Thus the focal length is 1 m.

Hence the object should be placed at 1 m from the concave mirror for parallel beam reflection.