File:Early Cooper Hewitt mercury vapor lamp.jpg
From Wikimedia Commons, the free media repository
Jump to navigation
Jump to search
Size of this preview: 384 × 599 pixels. Other resolutions: 154 × 240 pixels | 606 × 946 pixels.
Original file (606 × 946 pixels, file size: 126 KB, MIME type: image/jpeg)
File information
Structured data
Captions
Summary[edit]
DescriptionEarly Cooper Hewitt mercury vapor lamp.jpg |
English: One of the first mercury vapor lamps created by Peter Cooper Hewitt, which he invented and patented in 1903. This was the forerunner of the fluorescent lamp. It consisted of a sealed partially evacuated glass tube with electrodes at either end, with a small amount of liquid mercury inside. When a pulse of high voltage was applied an arc was started between the electrodes which evaporated the mercury. The electrons struck the mercury atoms, knocking off electrons, ionizing them, so the gas in the tube became electrically conductive, and a current flowed through the tube. When the electrons rejoined the atoms the atoms emitted light. The circular device below the lamp is the ballast, an inductor which produced a pulse of high voltage when the lamp was turned on, to start it. The mercury-vapor lamp was a lot more efficient than the incandescent lamp which was the dominant type of electric light at the time, but it produced a greenish light which was unpleasant, so its use was limited to office buildings and hallways and photographic uses. Later a fluorescent coating (a phosphor) was applied to the inside of the tube, which produced a pleasing white light when struck by ultraviolet light from the mercury vapor. This was the fluorescent lamp which has become most widely used light source today. |
Date |
before 1903 date QS:P,+1903-00-00T00:00:00Z/7,P1326,+1903-00-00T00:00:00Z/9 |
Source | Downloaded July 27, 2013 from Ray Stannard Baker 1903 Boys' Second Book of Inventions, McClure, Phillips and Co., New York, p. 305 on Google Books |
Author | Unknown authorUnknown author |
Licensing[edit]
Public domainPublic domainfalsefalse |
This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.
|
||
This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the rule of the shorter term for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.
|
File history
Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 06:44, 28 July 2013 | 606 × 946 (126 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
You cannot overwrite this file.
File usage on Commons
There are no pages that use this file.
File usage on other wikis
The following other wikis use this file:
- Usage on de.wikipedia.org
- Usage on en.wikipedia.org
- Usage on es.wikipedia.org
- Usage on fr.wikipedia.org
- Usage on nn.wikipedia.org
- Usage on ru.wikipedia.org
Metadata
This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.
JPEG file comment | Created with GIMP |
---|