All Derivations of Ray Optics Class 12 These important derivations are all from previous years question papers : All Derivations of Ray Optics Class 12 ( Important derivations) Five Marks a)With the help of a suitable ray diagram , derive the mirror formula for a concave mirror . b)The near point of a hypermetropic person is 50 cm from the eye . What is the power of the lens required to enable the person to read clearly a book held at 25cm from the eye ? (CBSE 2009) Trace the ray of light showing the formation of image due to a point object placed on the axis of a spherical surface separating the two media of refractive indices n1 and n2 . Establish the relation between the distances of the object , the image and the radius of curvature from the central point of the spherical surface . Hence , derive the expression of lens maker's formula . Or Draw the labelled ray diagram for the formation of image by a compound microscope . Derive the expression for th...