When a parallel rays of light incident on a mirror, they are reflected towards a fixed point on the principle axis. This point is called principle focus. The distance between mirror and principle focus is known as focal length. The formula for principle focus is;
1/ f= 1/ do + 1/ dI
f= focal length
do= distance between object and mirror
dI= distance between image and mirror
The reciprocal of focal length is equal to the sum of reciprocal of distance between mirror and image and reciprocal of distance between mirror and object.
1/ f= 1/ do + 1/ dI
f= focal length
do= distance between object and mirror
dI= distance between image and mirror
The reciprocal of focal length is equal to the sum of reciprocal of distance between mirror and image and reciprocal of distance between mirror and object.
