Question

When a spherical mirror is held towards the sun and its sharp image is formed on a piece of carbon paper for some time, a hole is burnt in the carbon paper.

1. What is the nature of spherical mirror?
2. Why is a hole burnt in the carbon paper?
3. At which point of the spherical mirror the carbon paper is placed?
4. What name is given to the distance between spherical mirror and carbon paper?
5. What is the advantage of using a carbon paper rather than a white paper?

Answer 1

1. The spherical mirror is concave.
2. A lot of the sun’s heat rays are concentrated at the point of the sun’s image, which burns a hole in carbon paper.
3. The carbon is placed at the focus.
4. The distance between the spherical mirror and the carbon paper is named the focal length.
5. A black carbon paper absorbs more heat rays and hence burns a hole more easily (than a white paper).