Question

Which of the following lenses should be used to read small letters?

• A. Convex lens of 10 cm focal length
• B. Concave lens of 10 cm focal length
• C. Convex lens of 20 cm focal length
• D. Concave lens of 20 cm focal length

Hint:

Convex lenses with small focal lengths provide high magnification, making them ideal for reading and magnifying objects.

Answer 1

The Correct Option is A

A convex lens of short focal length is used for reading small letters because it acts as a magnifying glass and forms a virtual, erect, and magnified image when the object is placed within its focal length. The shorter the focal length, the greater the magnification, making a convex lens of 10 cm more effective than 20 cm.