CHEMISTRY GLOSSARY

electromagnetic radiation spectrum    →   spektar elektromagnetskog zračenja

Wavelengths of electromagnetic waves can be shown with the help of electromagnetic radiation spectrum. Electromagnetic radiation spectrum is divided into several areas from γ-radiation of very short wavelengths and great energy to radio waves with wavelengths up to 1 000 m. The human eye can only see a narrow part of the electromagnetic spectrum - visible radiation.

electromagnetic spectrum    →   elektromagnetski spektar

See Electromagnetic radiation spectrum

line spectrum    →   linijski spektar

Red-hot gases give line spectrum, i.e. is they emit electromagnetic rays of defined wavelengths. That kind of emission line of spectrum is characteristic of each chemical element.

X-ray spectrum    →   spektar X-zraka

X-ray spectrum is a set of characteristic X-ray frequencies or wavelengths produced by a substance used as a target in an X-ray tube. Each element has a characteristic X-ray spectrum, and there is a strong correlation between atomic number and the frequencies of certain lines in the X-ray spectrum.

infrared radiation    →   infracrveno zračenje

Infrared radiation is an electromagnetic radiation within the area from 1.0 μm to 300 μm, and is responsible for the transmission of radiant heat.

visible radiation    →   vidljivo zračenje

Human eye can only see electromagnetic radiation of wavelengths form 400 nm to 760 nm. This narrow part of electromagnetic spectrum is called visible radiation. Visible (white) light is a mixture of light of all kind of colours, it can be separated, with the help of a glass prism, into its component colours - visible light spectrum, and each colour corresponds to a certain area of wavelengths:

gamma radiation    →   gama-zračenje

Gamma radiation is electromagnetic radiation of extremely short wavelength. Gamma radiation ranges in energy from about 10^-15 J to 10^-10 J (10 keV to 10 MeV) (wavelength less than about 1 pm). Gamma rays are emitted by excited atomic nuclei during the process of passing to a lower excitation state.

Gamma rays are extremely penetrating and are absorbed by dense materials like lead and uranium. Exposure to gamma radiation may be lethal.

ultraviolet light    →   ultraljubičasto svjetlo

Ultraviolet light (UV light or UV radiation) is an electromagnetic radiation with a wavelength longer than that of x-rays, but shorter than that of visible light. Ultraviolet light can break some chemical bonds and cause cell damage.

beta radiation    →   beta zračenje

Streams of beta particles are known as beta ray or beta radiation. Beta rays may cause skin burns and are harmful within the body. A thin sheet of metal can afford protection to the skin.

blackbody radiation    →   zračenje crnog tijela

Blackbody radiation is the radiation emitted by a perfect blackbody, i.e., a body which absorbs all radiation incident on it and reflects none. The primary law governing blackbody radiation is the Planck Radiation Law, which governs the intensity of radiation emitted by unit surface area into a fixed direction (solid angle) from the blackbody as a function of wavelength for a fixed temperature. The Planck Law can be expressed through the following equation

where λ is the wavelength, h is Planck’s constant, c is the speed of light, k is the Boltzmann constant, and T is the temperature.