Question

Draw a ray diagram in each of the following cases to show what happens after reflection to the incident ray when

1. it is parallel to the principal axis and falls on a convex mirror.
2. it is falling on a concave mirror while passing through its principal focus.
3. it is coming oblique to the principal axis and falling on the pole of a convex mirror.

Answer 1

Ray diagram:

a. When it is parallel to the principal axis and falls on a convex mirror:

Whenever an incoming ray is parallel to the principal axis and strikes a convex mirror, it becomes divergent and appears to come from its focus following laws of reflection from the mirror.

b. When it is falling on a concave mirror while passing through its principal focus:

Whenever an incoming ray strikes a concave mirror while travelling through its primary focus, it must be reflected parallel to the principal axis.

c. When it is coming oblique to the principal axis and falling on the pole of a convex mirror:

Whenever an incident ray is oblique towards the primary axis and strikes the pole of a convex mirror, it must be reflected back at the same angle as the principal axis.