Question

Is aperture the diameter of mirror? If yes then tell me if it passes from centre of curvature?

Answer 1

No frnd......
Aperture is not the diameter of mirror.
Aperture is the total reflective surface of a mirror.
Or we can say that it is the portion which can be touched........

Answer 2

aperture is the length of the mirror in which light undergoes reflection
it's not diameter as spherical mirror is a part of hollow sphere silvered from a side
no it doesn't pass through the centre of curvature
see the pic