The langley (Ly) is a unit of heat transmission, especially used to express the rate of
solar radiation
Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument.
Solar irradiance is measured in watts per square metre ( ...
(or
insolation) received by the earth. The unit was proposed by
Franz Linke Franz may refer to:
People
* Franz (given name)
* Franz (surname)
Places
* Franz (crater), a lunar crater
* Franz, Ontario, a railway junction and unorganized town in Canada
* Franz Lake, in the state of Washington, United States – see ...
in 1942 and named after
Samuel Langley (1834–1906) in 1947.
Definition
One langley is
*1
thermochemical calorie
The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of o ...
per
square centimetre,
*41 840 J/m
2 (
joule
The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force applie ...
s per
square metre)
See also
*
Solar constant
*
Radiant exposure
In radiometry, radiant exposure or fluence is the radiant energy ''received'' by a ''surface'' per unit area, or equivalently the irradiance of a ''surface,'' integrated over time of irradiation, and spectral exposure is the radiant exposure per ...
References
Units of measurement
Non-SI metric units
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