first radiation constant
first radiation constant[′fərst ‚rād·ē′ā·shən ‚kän·stənt]
A constant appearing in the Planck radiation formula; its value depends on the form of the formula used; in the formula for power emitted by a blackbody per unit area per unit wavelength interval, it is 2π times Planck's constant, times the square of the speed of light, or approximately 3.74177 × 10-16 watt (meter)2. Symbolized c1; C1.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.