- hydrogen line
-
a spectral line of atomic hydrogen having a wavelength of about 21cm; used extensively in radio astronomy
Wikipedia foundation.
hydrogen line
Look at other dictionaries:
Hydrogen line — For hydrogen lines in general, see Hydrogen spectral series. The hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This… … Wikipedia
Hydrogen leak testing — is the normal way in which a hydrogen pressure vessel or installation is checked for leaks or flaws. There are various tests.*The Hydrostatic test, The vessel is filled with a nearly incompressible liquid usually water or oil and examined for… … Wikipedia
Hydrogen sulfide — Systematic name … Wikipedia
Hydrogen cyanide — IUPAC name … Wikipedia
Hydrogen — This article is about the chemistry of hydrogen. For the physics of atomic hydrogen, see Hydrogen atom. For other meanings, see Hydrogen (disambiguation). ← hydrogen → helium … Wikipedia
hydrogen — /huy dreuh jeuhn/, n. a colorless, odorless, flammable gas that combines chemically with oxygen to form water: the lightest of the known elements. Symbol: H; at. wt.: 1.00797; at. no.: 1; density: 0.0899 g/l at 0°C and 760 mm pressure. [1785 95;… … Universalium
Hydrogen atom — Stable Isotope isotope name = Hydrogen 1 isotope filename = hydrogen 1.png alternate names = protium mass number = 1 symbol = H num neutrons = 0 num protons = 1 abundance = 99.985% mass = 1.007825 spin = ½+ excess energy = 7288.969 error1 = 0.001 … Wikipedia
hydrogen bond — Bond Bond (b[o^]nd), n. [The same word as band. Cf. {Band}, {Bend}.] 1. That which binds, ties, fastens, or confines, or by which anything is fastened or bound, as a cord, chain, etc.; a band; a ligament; a shackle or a manacle. [1913 Webster]… … The Collaborative International Dictionary of English
Hydrogen vehicle — A hydrogen vehicle is a vehicle that uses hydrogen as its on board fuel for motive power. The term may refer to a personal transportation vehicle, such as an automobile, or any other vehicle that uses hydrogen in a similar fashion, such as an… … Wikipedia
Hydrogen chloride — HCl redirects here. For the acid, see Hydrochloric acid. Hydrogen chloride … Wikipedia
