Calculate the temperature at which a tung-
sten filament with an emissivity of 0.32
and a surface area of 7.9 × 10?5 m2 will
radiate energy at the rate of 43 W
in a room where the temperature is
24C. The Stephan-Boltzmann constant is
5.6696 × 10?8 W/m2
· K4 .
Answer in units of C