Why is reflection of light important?

Answer 1

Whenever a ray of light strikes a surface, at least some of the light is reflected --that is, it bounces off the surface toward a new direction. The surface does not have to be flat or shiny to reflect light; light bouncing off rough surfaces, such as grass or pavement, is reflected in many different directions. This is called diffuse reflection. However, if the surface is both flat and shiny, the light bouncing off it will behave in very specific ways--the reflected rays will be parallel, and they will reflect in an easily calculated angle. This type of reflection is called specular reflection, and it has been used by scientists for centuries to better understand light itself. In specular reflection, the light ray will strike a reflecting surface at some angle (known as the angle of incidence) and bounce away at another angle (the angle of reflection). These angles are measured relative to an imaginary line, called the normal, which is drawn from the point where the ray strikes the reflecting surface and is perpendicular to that surface. As measured from the normal, the angle of reflection will always be equal to the angle of incidence. This is the most important law governing the reflection of light and was first noted by the ancient Greek engineer Hero (first centurya.d. ).