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

Explanation

The spherical mirror formula is `(1)/(u)+(1)/(v)=(1)/(f)`…(i)
For a plane mirror, `R = oo`
`f = ( R)/(2) = oo`
From (i), `(1)/(u)+(1)/(v)=(1)/(oo) = 0` or `(1)/(v)= - (1)/(u)`
or `v = -u`
AS `u` is negative, `v` becomes `+`.
Hence, image of formed behind the mirror at the same distance as the object is in front of it. This is what happens in a plane mirror. hence the desired result.