A concave mirror of radius of curvature 50 cm is used to form an image of an object kept at a distance of 25 cm from the mirror on its principal axis. What will be the position of the image from the mirror?

The focal length (f) of a spherical mirror is defined as half of its radius of curvature (R). Given a concave mirror with a radius of curvature of 50 cm, the focal length is calculated as f = R/2 = 50/2 = 25 cm. According to the mirror formula, 1/f = 1/v + 1/u, where u is the object distance and v is the image distance. In this scenario, the object is placed at a distance of 25 cm from the mirror, which coincides exactly with the focal point (u = f = 25 cm). When an object is positioned at the principal focus of a concave mirror, the reflected rays emerge parallel to the principal axis. Consequently, these parallel rays never intersect on a finite plane, resulting in the formation of a real, inverted, and highly enlarged image at infinity.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > What you have learnt > p. 159