Search results
Results from the WOW.Com Content Network
Snell's law (also known as the Snell–Descartes law, the ibn-Sahl law, [1] and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.
Reflection of light is either specular (mirror-like) or diffuse (retaining the energy, but losing the image) depending on the nature of the interface.In specular reflection the phase of the reflected waves depends on the choice of the origin of coordinates, but the relative phase between s and p (TE and TM) polarizations is fixed by the properties of the media and of the interface between them.
Hero of Alexandria, in his Catoptrics (1st century CE), showed that the ordinary law of reflection off a plane surface follows from the premise that the total length of the ray path is a minimum. [35] Ibn al-Haytham, an 11th-century polymath later extended this principle to refraction, hence giving an early version of the Fermat's principle ...
Details of Fresnel's derivation, including the modern forms of the sine law and tangent law, were given later, in a memoir read to the French Academy of Sciences in January 1823. [24] That derivation combined conservation of energy with continuity of the tangential vibration at the interface, but failed to allow for any condition on the normal ...
A surface which obeys Lambert's law is said to be Lambertian, and exhibits Lambertian reflectance. Such a surface has a constant radiance / luminance , regardless of the angle from which it is observed; a single human eye perceives such a surface as having a constant brightness, regardless of the angle from which the eye observes the surface.
The reflection angle is equal to the incidence angle, and the amount of light that is reflected is determined by the reflectivity of the surface. The reflectivity can be calculated from the refractive index and the incidence angle with the Fresnel equations , which for normal incidence reduces to [ 42 ] : 44
Their derivation [1] [2] [3] relies on a time-reversal argument, so they only work when there is no absorption in the system. A reflection of the incoming field (E) is transmitted at the dielectric boundary to give rE and tE (where r and t are the amplitude reflection and transmission coefficients, respectively). Since there is no absorption ...
3.1 Planck's derivation. 4 ... Kirchhoff's law of thermal radiation refers to ... It is the site of refraction of radiation that penetrates it and of reflection of ...