heijastuslaki

Heijastuslaki, often translated as the law of reflection, is a fundamental principle in optics that describes how light bounces off a surface. It states that the angle of incidence is equal to the angle of reflection. The angle of incidence is the angle between the incoming ray of light, known as the incident ray, and the normal, which is an imaginary line perpendicular to the surface at the point of incidence. Similarly, the angle of reflection is the angle between the reflected ray of light and the normal.

Furthermore, the law of reflection dictates that the incident ray, the reflected ray, and the normal all lie in the same plane. This means that if you imagine a flat plane extending from the point where the light hits the surface, both the incoming and outgoing light rays will stay within that plane. This principle applies to all types of reflection, whether it's from a smooth, polished surface like a mirror or a rougher surface. The perceived clarity of the reflection depends on the smoothness of the surface; smoother surfaces lead to specular reflection, where parallel incident rays reflect as parallel rays, creating a clear image. Rougher surfaces cause diffuse reflection, where incident rays scatter in various directions. The law of reflection is crucial for understanding how we see objects, how mirrors work, and is a foundational concept in the design of optical instruments.