How does light behave when reflecting off a curved surface?

Light reflecting off a curved surface diverges or converges, depending on whether the surface is concave or convex.

When light hits a curved surface, its behaviour changes based on the shape of the surface. If the surface is concave, or curved inwards, the light rays will converge, or come together at a single point. This point is known as the focal point. The distance between the surface and the focal point is the focal length. Concave mirrors, for example, are used in telescopes and car headlights because they focus light into a single point.

On the other hand, if the surface is convex, or curved outwards, the light rays will diverge, or spread out. This makes the object appear smaller than it actually is. Convex mirrors are often used in car side mirrors or security mirrors in shops because they provide a wider field of view.

The law of reflection still applies to curved surfaces. This law states that the angle of incidence (the angle between the incoming light ray and the normal) is equal to the angle of reflection (the angle between the reflected light ray and the normal). However, because the surface is curved, the normal at each point on the surface is different. This causes the light rays to either converge or diverge after reflection.

In summary, the behaviour of light when it reflects off a curved surface depends on the shape of the surface. Concave surfaces cause light to converge, while convex surfaces cause light to diverge. The law of reflection still applies, but the curved surface changes the direction of the reflected light rays.