Question

how can you identify a plane concave and concave mirror by observing image formation​

Answer 1

The images formed by the convex mirrors are diminished in nature. ... The examples of concave mirrors are the mirrors used in automobile head lights, reflecting telescopes, torch lights, etc. The examples of convex mirrors are the mirrors used as rear side mirrors of vehicles, optical instruments, calling bell, etc

Answer 2

We identify to it's focal length when focal length is positive then we know concave mirror . And concave mirror trick is last word cave that mirror is make a cave that mirror is concave