The principal focus of the convex lens is a point on the principal axis where the light rays appear to be meeting after refraction from the lens as shown in the figure.F in the figure is the principal focus.
(a) With the help of a labelled diagram explain how a convex lens converges a beam of parallel light rays. Mark the principal axis, optical centre, principal focus and focal length of the convex lens on the diagram. (b) State whether the convex lens has a real focus or a virtual focus. (c) List some things that convex lens and concave mirror have in common.
What is the difference between focus and principal focus of concave and convex lenses