Which one of the following lenses would you prefer to use while reading very small letters printed on a label ?

To read very small letters, a magnifying glass is required, which is a convex (converging) lens [t2][t5]. A convex lens produces a virtual, erect, and magnified image when the object is placed within its focal length [t4]. The magnification of a lens is inversely proportional to its focal length; specifically, the power of a lens is defined as the reciprocal of its focal length (P = 1/f) [c4]. A lens with a smaller focal length has greater power and causes light rays to bend at larger angles, focusing them closer to the optical centre and providing higher magnification [c4]. Conversely, concave lenses are diverging and typically produce diminished images, making them unsuitable for magnifying small print [t1][t6]. Therefore, a convex lens with a small focal length is the most effective choice for reading small letters clearly.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > 9.3.8 Power of a Lens > p. 157
2. [2] https://www.elearning.rtb.gov.rw/mod/book/tool/print/index.php?id=1024