Question

Prove that spherical mirror formula is applicable equal to a plane mirror.

Answer 1

For plane mirror the usual mirror formula can be used

usual mirror formula involves object distance u

image distance v and

f -the focal length

which is equal to R/2 where R is the radius of curvature.

the form of equation is

1/u + 1/v = 1/f = 2/R

the question is what is radius of curvature of a plane mirror?

if one takes the radius of curvature R to be very large compared to u and v then the curved surfaces will be planes.

so if R is infinitely large then 2/R goes to zero.

so the plane mirror formula reduces to

1/u + 1/v = 0 means u = -v

so if object is placed in front of mirror , the image will be located behind the mirror.

however as the formula is trivial so its not used. but when several media gets coupled to plane mirror this concept is used .