An incandescent filament of surface area radiates at and at .
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Modern Physics · Modern Physics
Problem
An incandescent filament of surface area 2.0×10−5m2 radiates 4.8×104Wm−2 at 1200K and 9.5×104Wm−2 at 1500K.
(i) Show quantitatively whether these two observations are consistent with a fourth-power dependence of emissive power on absolute temperature.
(ii) Taking the accepted numerical value of the Stefan–Boltzmann constant, determine the emissivity of the filament material.
(iii) Using your emissivity, calculate the emissive power you would expect from the same filament when its temperature is raised to 1700K.