Posted by robert on .
In one room the radiator has a dark color (emissitivity = 0.818). It has a temperature of 64.8 oC. The new owner of the house paints the radiator a lighter color (emissitivity = 0.417). Assuming that it emits the same radiant power as it did before being painted, what is the temperature (in degrees Celsius) of the newly painted radiator?

physics 
drwls,
The StefanBoltzmann equation must use temperature in K.
T1 = 64.8 C = 338.0 K
If the radiating area stays the same,
0.818 T1^4 = 0.417 T2^4, so
T2 = 1.1835*T1 = 400.0 K = 126.8 C