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A 175-watt mercury-vapor light approximately 15 seconds after starting. A closeup of a 175-W mercury-vapor lamp. The small diagonal cylinder at the bottom of the arc tube is a resistor which supplies current to the starter electrode. A mercury-vapor lamp is a gas-discharge lamp that uses an electric arc through vaporized mercury to produce ...
Germicidal UV for disinfection is most typically generated by a mercury-vapor lamp. Low-pressure mercury vapor has a strong emission line at 254 nm, which is within the range of wavelengths that demonstrate strong disinfection effect. The optimal wavelengths for disinfection are close to 260 nm. [70]: 2–6, 2–14 Mercury vapor lamps may be ...
The spectrum of light emitted from a fluorescent lamp is the combination of light directly emitted by the mercury vapor, and light emitted by the phosphorescent coating. The spectral lines from the mercury emission and the phosphorescence effect give a combined spectral distribution of light that is different from those produced by incandescent ...
A mercury vapor lamp is a line lamp, meaning it emits light near peak wavelengths. By contrast, a xenon arc has a continuous emission spectrum with nearly constant intensity in the range from 300-800 nm and a sufficient irradiance for measurements down to just above 200 nm.
A deuterium arc lamp (or simply deuterium lamp) is a low-pressure gas-discharge light source often used in spectroscopy when a continuous spectrum in the ultraviolet region is needed. Plasma "arc" or discharge lamps using hydrogen are notable for their high output in the ultraviolet, with comparatively little output in the visible and infrared.
Some lamps use a deep-bluish-purple Wood's glass optical filter that blocks almost all visible light with wavelengths longer than 400 nanometers. [37] The purple glow given off by these tubes is not the ultraviolet itself, but visible purple light from mercury's 404 nm spectral line which escapes being filtered out by the coating.
Wavelength of peak (nm) Species producing peak Actual line location (nm) 1 405.4 mercury: 404.656 2 436.6 mercury 435.833 3 487.7 terbium from Tb 3+ ~485 to 490 4 542.4 terbium from Tb 3+ ~543 to 544 5 546.5 mercury 546.074 6 577.7 likely terbium from Tb 3+ or mercury 576.960 for Hg or ~578 for Tb 7 580.2 mercury or terbium from Tb 3+
Photochemical immersion well reactor (50 mL) with a mercury-vapor lamp.. Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible (400–750 nm), or infrared radiation (750–2500 nm).