An image is thus a point-to-point
correspondence with the object established through
reflection and/or refraction In principle, we can take any two rays emanating
from a point on an object, trace their paths, find their
point of intersection and thus, obtain the image of
the point due to reflection at a spherical mirror In
practice, however, it is convenient to choose any two
of the following rays:
(i)
The ray from the point which is parallel to the
principal axis The reflected ray goes through
the focus of the mirror