Actinometer

n. instrument that measures actinic action in radiant energy

Actinometers are instruments used to measure the heating power of radiation. They are used in meteorology to measure solar radiation.An actinometer is a chemical system or physical device which determines the number of photons in a beam integrally or per unit time. This name is commonly applied to devices used in the ultraviolet and visible wavelength ranges. For example, solutions of iron(III) oxalate (e.g. potassium ferrioxalate) can be used as a chemical actinometer, while bolometers, thermopiles, and photodiodes are physical devices giving a reading that can be correlated to the number of photons detected.
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Noun
1. an instrument for measuring the intensity of electromagnetic radiation (usually by the photochemical effect)
(hypernym) measuring instrument, measuring system, measuring device

(n.)
An instrument for measuring the direct heating power of the sun's rays.
  

(n.)
An instrument for measuring the actinic effect of rays of light.
  

n.
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