Optics

Becke method [after the Austrian scientist F.

White light , electromagnetic radiation of a complex spectral composition that produces in people with normal colour vision a sensation neutral in colour.

Binoculars , (French binocle, from the Latin bini — pair, two, and oculus—eye), an optical instrument for viewing distant objects with both eyes, and also for measuring angles and distances.

Binocular vision , (from the Latin bini — pair, two, and oculus — eye), vision with two eyes.

Biot's law - determines the angle φ through which the plane of polarisation of linearly polarised light is rotated as it passes through a layer of a non-crystalline substance (a liquid, or a solution in an inactive solve…

Bioluminescence - the luminescence of organisms, connected with the processes of their vital activity.

Lustre , a characteristic of the property of a surface that reflects light.

The Bragg-Wulff condition , determines the directions in which maxima of intensity can arise when X-radiation is elastically scattered by a crystal in the diffraction of X-rays.

Brewster's law, the relation between the refractive index n of a dielectric and the angle of incidence φ of natural (unpolarised) light on it at which the light reflected from the surface of the dielectric is completely …

The angle of incidence of a light ray at which the light reflected from a dielectric is completely polarised.

The Bouguer-Lambert-Beer law , determines the attenuation of a beam of monochromatic light as it passes through an absorbing substance.

Vacuum spectroscopy , the spectroscopy of the short-wavelength UV region and of soft X-radiation (from 2*10 2 to 0.4—0.6 nm).

Dioptrics , (Greek dioptrika, from dia — through and opteuo — I see), the traditional (and gradually falling out of use) name of the branch of geometrical optics that deals with the refraction of light as it passes throu…

Dioptre , (D), the unit of optical power of lenses and of other axially symmetric optical systems; 1 dioptre is equal to the optical power of a lens or a spherical mirror with a focal length of 1 m.

(unpolarised light), optical radiation whose electromagnetic field strength changes direction rapidly and at random, all directions of oscillation perpendicular to the light rays being equally probable.

A line of equal illuminance, expressed in phots.

Cathodoluminescence , luminescence that arises when a phosphor is excited by an electron beam (cathode rays); one of the forms of radioluminescence.

Catoptrics , (from the Greek katoptrikos — of a mirror, reflected in a mirror), a historical and now obsolete name for the branch of geometrical optics that dealt with the optical properties of reflecting surfaces (optic…

Caustic surface , (from the Greek kaustikos — burning) in optics, the surface that envelops a family of light rays emitted by a luminous point and passed through an optical system.

The body of methods for studying atomic nuclei by the radiation that accompanies nuclear transformations and the transitions of nuclei from one state to another.