Why doesn't a ray of light passing through the optical centre of a lens deviate?
We use very thin lens, so that a light ray passing through its optical centre goes un-deviated.
A ray of light after refraction through a lens emerges parallel to the principal axis of the lens. The incident ray passes through :
(a) its optical centre
(b) its first focus
(c) its second focus
(d) the centre of curvature of the first surface.