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Fluorescent lamps using conventional magnetic ballasts flicker at twice the supply frequency. Electronic ballasts do not produce light flicker since the phosphor persistence is longer than a half cycle of the higher operation frequency of 20 kHz. The 100–120 Hz flicker produced by magnetic ballasts is associated with headaches and eyestrain. [8]
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By mixing these compounds with shellac, they invented the first black light fluorescent paints. [3] Joseph used these paints in his amateur magic show and sold magic kits based on the black light fluorescent costumes they created. [3] The brothers established the Fluor-S-Art Co. in 1934 to develop and sell black light paints for advertising ...
A flicker light bulb, flicker flame light bulb or flicker glow lamp is a gas-discharge lamp which produces light by ionizing a gas, usually neon mixed with helium and a small amount of nitrogen gas, by an electric current passing through two flame shaped electrode screens coated with partially decomposed barium azide. The ionized gas moves ...
A light bulb is suspended in the center of the cylinder with the rotation speed making light emanate from the holes at a consistently pulsating frequency range of 8–13 flickers per second. It is meant to be looked at through closed eyelids, upon which moving yantra -like mandala visual patterns emerge, and an alpha wave mental state is induced.
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 ...
SmugMug is a paid image sharing, image hosting service, and online video platform on which users can upload photos and videos. The company also facilitates the sale of digital and print media for amateur and professional photographers. [3] In 2018, SmugMug purchased Flickr. [4]
New York Daily News (1880–2007), online photo archive DailyNewsPix, with photographs dating back to 1880 New York Public Library: ≈ 30% Public domain: 922,400+ (May 2024) [3] No No Yes English Pexels: Pexels license: Yes No Yes Pixabay: Pixabay license: 950,000+ (May 2017) Yes No Yes English (Default) + 25 other languages Pond5: Royalty-free