Plane mirror focal length
Classical Mechanics
Level
3
Which statement is most appropriate for plane mirrors?
Focal length is finite because rays meet at a point.
Focal length is 0 because parallel rays do not meet after reflection
Focal length is defined for lens, not for mirror!
Focal length is infinity because it is limit of spherical mirrors where R tends to infinite
Focal length is infinite because parallel rays meet at a finite point after striking plane mirror
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1 solution
The radius of curvature of a plane mirror is zero. Plane mirror is considered to be the maximum limit of spherical mirrors. Therefore, there are many light rays converging and diverging at many points on a mirror. So the focal length is infinite.