What is magnification?

An object is placed at the focus of concave lens having focal length /. What is the magnification and distance of the image from the optical centre of the lens ?

A concave mirror produces 10 cm long image of an object of height 2 cm. What is the magnification produced?

(i) At what distance should the lens be held from the card sheet in order to view the squares distinctly with the maximum possible magnifying power ? (ii) What is the magnification in this case ? (iii) Is the magnification equal to magnifying power in this case ? Explain.