Also called Crookes radiometer. an instrument for demonstrating the transformation of radiant energy into mechanical work, consisting of an exhausted glass vessel containing vanes that revolve about an axis when exposed to light.
an instrument for detecting and measuring small amounts of radiant energy.
- ra·di·o·met·ric [rey-dee-oh-me-trik], /ˌreɪ di oʊˈmɛ trɪk/, adjective
- ra·di·om·e·try, noun
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How to use radiometer in a sentence
Thus it appears that we have been able to show by very definite experimental evidence that the radiometer is a heat engine.Scientific Culture, and Other Essays | Josiah Parsons Cooke
Another illustration of the power of cooled charcoal to produce high vacua is afforded by a Crookes radiometer.
To a radiometer (fig. 6) with attached charcoal bulb B was sealed a tube ending in a small bulb A containing a globule of mercury.
Count Bathyani recently took up a radiometer to a height of about a mile.The Galaxy, April, 1877 | Various
The monitors were synchronized with the radiometer and changed view at every ten-mile marker.Code Three | Rick Raphael
British Dictionary definitions for radiometer
any instrument for the detection or measurement of radiant energy
- radiometric (ˌreɪdɪəʊˈmɛtrɪk), adjective
- radiometry, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for radiometer
A device used to detect or measure radiation. Radiometers generally consist of a glass bulb containing a rarefied gas in which four diamond-shaped paddles are mounted on a central axis. Each paddle is black on one side and silvery on the other. When radiation such as sunlight strikes them, the black side absorbs radiation and the silvery side reflects it, resulting in a temperature difference between the two sides and causing motion of gas molecules around the edges of the paddles. This motion of the surrounding gas molecules causes the paddles to spin. Precision radiometers, which use a complete vacuum rather than a gas, exploit the difference in radiation pressure on either side of the paddles to cause them to spin. Radiometers measure the intensity of radiation by measuring the rate of spin of the paddles. Also called light mill
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