(I) Calculate the distance of an object of height h from a concave mirror of radius of curvature 20 cm, so as to obtain a real image of magnification 2. Find the location of image also.
(ii) Using mirror formula, explain why does a convex mirror always produce a virtual image.

An object is placed 40 cm from a convex lens of focal length 30 cm, If a concave lens of focal length 50 cm is introduced between the convex lens and the image formed such that it is 20 cm from the convex lens, find the change in the position of the image.

A ray PQ incident normally on the refracting face BA is refracted in the prism BAC made of material of refractive index 1.5. Complete the path of the ray through the prism. From which face will the ray emerge? Justify your answer.

Draw a plot showing the variation of power of a lens with the wavelength of the incident light.

A concave lens is kept in contact with a convex lens of focal length 20 cm. The combination behaves as a convex lens of focal length 50 cm. Find the power of concave lens.