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[boh-lom-i-ter, buh-] /boʊˈlɒm ɪ tər, bə-/
noun, Physics.
a device for measuring minute amounts of radiant energy by determining the changes of resistance in an electric conductor caused by changes in its temperature.
1880-85; < Greek bol() ray + -o- + -meter
Related forms
[boh-luh-me-trik] /ˌboʊ ləˈmɛ trɪk/ (Show IPA),
bolometrically, adverb Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for bolometrically


a sensitive instrument for measuring radiant energy by the increase in the resistance of an electrical conductor
Derived Forms
bolometric (ˌbəʊləˈmɛtrɪk) adjective
bolometrically, adverb
bolometry, noun
Word Origin
C19: from bol-, from Greek bolē ray of light, stroke, from ballein to throw + -meter
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Encyclopedia Article for bolometrically


instrument for measuring radiation by means of the rise in temperature of a blackened metal strip in one of the arms of a resistance bridge. In the first bolometer, invented by the American scientist Samuel P. Langley in 1880, a Wheatstone bridge was used along with a galvanometer that produced a deflection proportional to the intensity of radiation for small deflections. A later bolometer consists of four platinum gratings (each of which is made of a series of strips) inserted in the arms of a resistance bridge; two of these gratings, in opposite arms of the bridge, are placed one behind another, so that the openings of one are opposite the strips of the other and are exposed to the radiation, the other opposite pair being shielded; this arrangement doubles the effect on the galvanometer and also compensates for any extraneous temperature changes. Changes in temperature as small as 0.0001 C may be detected in this way

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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