When does a ray of light emerge parallel to the principal exis after refraction in a concave lens?
A ray starting from the focus of a concave lens becomes parallel to the principal axis after refraction.
A ray of light, after rerfraction through a concave lens emerges parallel to the principal axis. (a) Draw a ray diagram to show the incident ray when produced meets the principal axis at point F. (b) Name the point F.
A ray of light after refraction through a convex lens emerges parallel to the principal axis. (a) Draw a ray diagram to show it. (b) The incident ray passes through a point F on the principal axis. Name the point F.