### Correct Option: C. At the focal point of the mirror ### Detailed Explanation: When a parallel beam of light strikes a concave mirror, the behavior of the light rays can be understood through the principles of reflection and the geometry of the mirror. 1. **Understanding Concave Mirrors**: - A concave mirror is a spherical mirror that curves inward, resembling a portion of the interior of a sphere. It has a focal point (F) where light rays that are parallel to the principal axis converge after reflection. 2. **Incident Light Rays**: - When a parallel beam of light (like sunlight) strikes the concave mirror, each ray can be considered to be coming from a point at infinity. This means that the rays are essentially parallel to each other and to the principal axis of the mirror. 3. **Reflection of Light Rays**: - According to the law of reflection, the angle of incidence (the angle between the incoming ray and the normal to the surface at the point of incidence) is equal to the angle of reflection (the angle between the reflected ray and the normal). - For a concave mirror, when these parallel rays hit the mirror, they reflect off the surface and converge at a specific point. 4. **Convergence at the Focal Point**: - The focal point of a concave mirror is located halfway between the mirror's surface and its center of curvature (C). The focal length (f) is defined as the distance from the mirror's surface to the focal point. - The geometry of the mirror ensures that all parallel rays reflecting off the mirror will converge at this focal point. This is a fundamental property of concave mirrors and is used in applications like telescopes and headlights. ### Why Other Options Are Incorrect: - **Option A: At a point located at the center of curvature**: - The center of curvature (C) is the center of the sphere from which the mirror is a part. While some rays may reflect and pass through this point, the primary behavior of parallel rays is to converge at the focal point, not the center of curvature. - **Option B: At a point located beyond the center of curvature**: - This option suggests that the rays converge at a point further away than the center of curvature. However, this is not accurate for parallel rays striking a concave mirror. They converge at the focal point, which is always located between the mirror's surface and the center of curvature. - **Option D: They will diverge and not converge at any point**: - This option is incorrect because it contradicts the fundamental behavior of concave mirrors. The design of the mirror ensures that parallel rays do indeed converge at the focal point, rather than diverging. ### Summary of Key Points: - **Concave mirrors reflect parallel rays to a single point called the focal point (F)**. - **The focal point is located between the mirror's surface and the center of curvature (C)**. - **The law of reflection states that the angle of incidence equals the angle of reflection**. - **Understanding the geometry of the mirror is crucial for predicting the behavior of light rays**. This understanding of concave mirrors and the behavior of light is essential for various applications in optics and physics.