Talbot 1 (T)
Talbot 1 (T) :
A unit of luminous (light) energy. One talbot is the energy carried by a light flux of one lumen in one second, that is, the talbot is the same as the lumen second (lm·s). For light of wavelength 555 nanometers (nm), the wavelength to which the eye is most sensitive, the talbot equals 1.464 millijoule. For other wavelengths l, the talbot equals 1.464·V(l) millijoules, where V(l) is the "luminous efficiency," a factor representing the relative sensitivity of the eye at wavelength l. Although the talbot is compatible with the SI, it has not been accepted as part of the International System; the symbol T would not be acceptable since it duplicates the symbol for the tesla. The unit, previously called the lumberg, is now named for the British physicist W.H. Fox Talbot (1800-1877)
