CHEMISTRY GLOSSARY

resonant frequency    →   rezonantna frekvencija

All vibrating systems have one or more resonant frequencies, which depend on system characteristics. If an external force is applied on the system at that frequency, the vibrations will be much greater than at slight different frequencies.

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frequency    →   frekvencija

Frequency (ν) is the number of cycles of a periodic phenomenon divided by time. Hertz (Hz) is the SI derived unit, with a special name, for frequency, equal to s^-1. It was named after the German scientist Heinrich Hertza (1857-1894).

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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.

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harmonic oscillation    →   harmonička oscilacija

Harmonic is an oscillation having a frequency is a simple multiple of a fundamental sinusoidal oscillation. The fundamental frequency of a sinusoidal oscillation is usually called the first harmonic. The second harmonic has a frequency twice that of the fundamental, and so on.

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hertz    →   herc

Hertz (Hz) is the SI derived unit, with a special name, for frequency. The hertz is the frequency of a periodic phenomenon of which the period is one second (Hz = 1 s^-1). It was named after the German scientist Heinrich Hertza (1857 - 1894).

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impedance    →   impedancija

Impedance is the analogue of the resistance or resistivity when applied to alternating current. That is, it is a measure of a material’s inability to carry the electrical current. In many materials the impedance varies as the frequency of the applied electrical potential changes, due to the properties of the conducting liquid or solid. In electrochemistry, the impedance of the electrodes is also frequency dependent.

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monochromator    →   monokromator

Monochromator (from the Greek words mono and chroma meaning single and colour) is an optical device based on dispersion of light by one or more prisms or diffraction gratings into its constituent wavelengths, which are utilized in turn.

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photon    →   foton

Photon is an elementary particle of zero mass and spin 1/2. The photon is involved in electromagnetic interactions and is the quantum of electromagnetic radiation. The photon may also be regarded as a unit of energy equal to

where h is Planck constant and ν is the frequency of the radiation.

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Planck constant    →   Planckova konstanta

Planck constant (h) is a constant that, when multipled by the frequency of radiation gives the quantity of energy contained in one quantum.

Equal to 6.626 075 5(40)·10^-34 J s. It was named after Max Planck (1858-1947).

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quantum    →   kvant

Quantum is the smallest quantity of energy that can be emitted (or absorbed) in the form of electromagnetic radiation. Energy of a quantum (E) is equal to

where h is Planck constant and ν is the frequency of radiation.

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