A light bulb radiates most strongly at a wavelength of about 3000 nanometers. How hot is its filament?
2 answers
The Wien displacement law will tell you it is about 1000 K. Actually, the filament of a tungsten lamp is hotter than that-- more like 2500 K. The emissivity changes with wavelength. I do not believe their statement about the wavelength of maximum emission. Perhaps they are counting the radiation from the glass, which domimates at 3000 nm.
1000K
1 answer