CHEMISTRY GLOSSARY

blackbody    →   crno tijelo

In radiation physics, an ideal blackbody is a theoretical object that absorbs all the radiant energy falling upon it and emits it in the form of thermal radiation. Planck’s radiation law gives the power radiated by a unit area of blackbody, and the Stefan-Boltzman law expresses the total power radiated.

Brownian motion    →   Braunovo gibanje

Brownian motion is the continuous random movement of small particles suspended in a fluid, which arise from collisions with the fluid molecules. First observed by the British botanist R. Brown (1773-1858) when studying pollen particles. The effect is also visible in particles of smoke suspended in a gas.

candela    →   kandela

Candela (cd) is the SI base unit of luminous intensity.

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×10¹² Hz and that has a radiant intensity in that direction of 1/683 watt per steradian.

chemiluminescence    →   kemiluminiscencija

Chemiluminescence is energy release in form of electromagnetic radiation during a chemical reaction.

deuterium lamp    →   deuterijeva svjetiljka

Deuterium or hydrogen lamp is used as a source of continuous radiation in UV part of the spectrum.

electromagnetic spectrum    →   elektromagnetski spektar

See Electromagnetic radiation spectrum

electromagnetic wave    →   elektromagnetski val

All matter absorbs and emits radiation covering a broad band of frequencies and wavelengths. Thus electromagnetic radiation has the velocity of light (2.998×10⁸ ms^-1) and arises from the vibrating electric charges in atoms and bonds. The range of wavelengths, also known as the electromagnetic spectrum, is shown below:

fire    →   vatra

Fire is the manifestation of rapid combustion, or combination of materials with oxygen. The flame is the visible portion of the fire.

fluorescence    →   fluorescencija

Fluorescence is a luminescence phenomenon in which electron returns to it's ground state almost instantaneously (less than 10^-8 second), and in which emission from a luminescent substance ceases when the exciting source is removed. Fluorescence is characterized by radiation emission in all directions.

gray    →   grej

Gray (Gy) is the SI derived unit of absorbed dose of radiation. The gray is the absorbed dose when the energy per unit mass imparted to matter by ionising radiation is one joule per kilogram (Gy = J/kg). The unit was named after the British scientist Louis Harold Gray (1905-1965).