The mirror used for the head light of a car is

Car headlights utilize concave reflectors to produce a powerful, parallel beam of light. While basic physics textbooks often categorize these as concave spherical mirrors [2], advanced optical engineering prefers a parabolic concave shape to eliminate spherical aberration. A spherical mirror does not have a single well-defined focal point for all rays, causing light to scatter [2]. In contrast, a parabolic reflector is specifically designed so that a light source placed at its focus reflects all rays perfectly parallel to the axis [3]. This property makes parabolic concave mirrors the ideal choice for projecting long-distance beams in searchlights and vehicle headlights [3]. Although spherical concave mirrors are a common approximation in introductory texts, the functional requirement for a collimated beam in modern automotive design is best met by the parabolic concave geometry [3].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > Uses of concave mirrors > p. 140
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 10: Light: Mirrors and Lenses > Activity 10.3: Let us explore > p. 156
3. [3] https://en.wikipedia.org/wiki/Parabolic_reflector