| first radiation constant [`fǝrst ´rād·ē`ā·shǝn ´kän·stǝnt] STATISTICAL MECHANICS 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 3.7415 × 10-16 watt (meter)2. Symbolized c1; C1. |