| 词条 | Lumen second |
| 释义 |
In photometry, the lumen second (lm⋅s) is the SI derived unit of luminous energy. It is based on the lumen, the SI unit of luminous flux, and the second, the SI base unit of time. The lumen second is sometimes called the talbot (symbol T). This name was coined in 1937 by the Committee on Colorimetry, Optical Society of America, in honor of the early photographer William Fox Talbot.[1] The talbot is exactly equal to the lumen second: 1 T = 1 lm⋅s The use of the symbol T for talbots conflicts with T as the symbol for the tesla, the SI unit of magnetic flux density. An older name for the lumen second was the lumberg.{{Citation needed|date=August 2011}} The photometric unit lumerg, also proposed by the Committee on Colorimetry in 1937, correlates with the old CGS unit erg in the same way that the lumen second correlates with the radiometric unit joule, so that 107 lumerg = 1 lm⋅s.[1] {{SI_light units}}References1. ^1 Loyd Ancile Jones. Colorimetry: Preliminary draft of a report on nomenclature and definitions. Journal of the Optical Society of America, Volume 27, page 211 (June 1937): “Referring again to Table I, terms (21) and (22) represent names for units which the committee has voted to adopt. The decision was almost unanimous in the case of recommending talbot as a psychophysical correlate of joule. The vote on lumerg as the psychophysical correlate of the erg was less unanimous.” 3 : Photometry|Units of luminous energy|SI derived units |
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