The focal length of a plane mirror is:

விடையைக் காட்டு & விளக்கம்

விடை: (D) Infinity

விளக்கம்

A plane mirror can be seen as a sphere of infinite radius, so its focal length is infinite.

(A) தவறு
Wrong: a plane mirror has no finite focus.
(B) தவறு
Wrong: a plane mirror has no finite focus.
(C) தவறு
Wrong: a plane mirror has no finite focus.
(D) சரி
Correct: its radius of curvature is infinite, so f = R/2 is infinite.