# Lumen second

Physical unit
Unit name Lumen second
Unit symbol ${\ displaystyle \ mathrm {lms}}$
Physical quantity (s) Amount of light
Formula symbol ${\ displaystyle E}$
dimension ${\ displaystyle {\ mathsf {J \; T}}}$
system International system of units
In SI units ${\ displaystyle \ mathrm {1 \, lm \, s = 1 \; lm \ cdot 1 \; s}}$
Derived from Lumens , second

Lumen second ( unit symbol lms ) is the SI unit of the amount of light . The amount of light is calculated as the integral of a luminous flux (SI unit lumen ) over time (SI unit second ); accordingly, its SI unit is the product of lumen and second:

${\ displaystyle \ mathrm {1 \, lm \, s = 1 \, lm \ cdot 1 \, s}}$

The unit is also called Talbot (after William Henry Fox Talbot ) or Lumberg , but these special names are not accepted by the organs of the International Meter Convention for use with SI units, nor are legal units in the EU in metrology .

Simultaneously with the Lumberg unit, the Lumerg was created, which was defined according to the ratio between Erg and Joule , as 1 lumerg = 10 −7  lms.

In practice, the lumen-hour (lmh) is often used as a measure, which is the amount of one lumen over an hour.

## Individual evidence

1. Thomas Jüstel, Sebastian Schwung: Phosphors, light sources, lasers, luminescence . Springer, Berlin, Heidelberg 2016, ISBN 978-3-662-48455-5 , pp. 96 , doi : 10.1007 / 978-3-662-48455-5 .