Which of the following lenses would you prefer to use while reading small letters found in a dictionary ?

Options

A. A convex lens of focal length 50 cm
B. A concave lens of focal length 50 cm
C. A convex lens of focal length 5 cm
D. A concave lens of focal length 5 cm

Answer

C

Explanation

A magnified image of an object will be obtained when it is placed between the radius of curvature and focal length of a convex lens. Magnification is also higher for convex lenses having shorter focal length. Therefore, for reading small letters, a convex lens of focal length 5 cm should be used.