Langley unit
Encyclopedia
The langley is a unit of energy distribution over area. It is used to measure solar radiation (or insolation
). The unit was named after Samuel Pierpont Langley
(1834-1906) in 1947.
Insolation
Insolation is a measure of solar radiation energy received on a given surface area in a given time. It is commonly expressed as average irradiance in watts per square meter or kilowatt-hours per square meter per day...
). The unit was named after Samuel Pierpont Langley
Samuel Pierpont Langley
Samuel Pierpont Langley was an American astronomer, physicist, inventor of the bolometer and pioneer of aviation...
(1834-1906) in 1947.
Definitions
- One langley is one thermochemical calorieCalorieThe calorie is a pre-SI metric unit of energy. It was first defined by Nicolas Clément in 1824 as a unit of heat, entering French and English dictionaries between 1841 and 1867. In most fields its use is archaic, having been replaced by the SI unit of energy, the joule...
per square centimetre. - In SI units, one langley is 41840.00 J/m² (or jouleJouleThe joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
s per square metreSquare metreThe square metre or square meter is the SI derived unit of area, with symbol m2 . It is defined as the area of a square whose sides measure exactly one metre...
). - In more common units, one Langley is 11.622 watt-hours per square metre.