Reflection (physics) Guide, Meaning , Facts, Information and Description
Reflection is the abrupt change in direction of a wave front at an interface between two dissimilar media so that the wave front returns into the medium from which it originated. Examples are the reflection of light, of sound and of water waves.
Reflection of light may be "specular" (i.e., mirror-like) or "diffuse" (i.e., not retaining the image, only the energy) according to the nature of the interface. Depending on the nature of the interface, i.e., dielectric-conductor or dielectric-dielectric, the phase of the reflected wave may or may not be inverted.
Specular (mirror-like) reflection
In fact, reflection of light may occur whenever light travels from a medium of a given refractive index into a medium with a different refractive index. In the most general case, a certain fraction of the light is reflected from the interface, and the remainder is refracted. Solving Maxwell's equations for a light ray striking a boundary allows the derivation of the Fresnel equations, which can be used to predict how much of the light is reflected, and how much is refracted in a given situation. Total internal reflection of light from a denser medium occurs if the angle of incidence is above the critical angle.
