The following rays are used to guess the position of the image formed by a concave mirror.
i) A ray parallel to the principal axis passing through principal focus (F) after reflection from a concave mirror.
ii) A ray passing through ‘F’ becomes parallel to principal axis after reflection from a concave mirror.
iii) A ray passing through ‘C’ is reflected back along the same path after reflection from a concave mirror.
iv) A ray incident obliquely to the principal axis towards the pole P, on the concave mirror is reflected obliquely, following the laws of reflection.
