If an object is placed at the focus of a convex lens, its image is

When an object is placed at the principal focus (F1) of a convex lens, the light rays emerging from the lens are parallel to each other [1]. According to the principles of geometrical optics, parallel rays are considered to meet at infinity, meaning the image is formed at an infinite distance [1]. This can also be mathematically derived from the thin lens formula (1/f = 1/v - 1/u); when the object distance (u) equals the focal length (f), the image distance (v) tends toward infinity. While some interpretations suggest that 'no image is formed' because the rays never intersect, in standard physics curriculum and ray diagrams, this scenario is defined as the image being formed at infinity [1]. The resulting image is highly enlarged, real, and inverted [1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > Activity 9.12 > p. 152