Question

to construct ray diagram we ude two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. list these 2 rays and state the path of these rays after reflection.

Answer 1

Two rays are following for ray diagram.

1. When the incident light ray is parallel to the principal axis.

In this case, the reflected ray will pass through the focus of a concave mirror, or it appears to pass through the focus of a convex mirror.

2.When the incident ray passes through or appears to pass through the centre of curvature.

In this case, light after reflecting from the spherical surface moves back in the same path. This happens because light is incident perpendicularly on the mirror surface.