A tungsten filament inside an electric lamp operates at an average temperature of
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Modern Physics · Modern Physics
Problem
A tungsten filament inside an electric lamp operates at an average temperature of 2800K. Take the required constant b=2.9×10−3mK where necessary.
(a) Calculate the wavelength corresponding to the maximum intensity of radiation emitted by the filament.
(b) Identify the region of the electromagnetic spectrum in which this wavelength lies, and state whether the filament appears nearly white or coloured to the human eye.
(c) If the filament temperature is lowered to 2200K, will the apparent colour shift toward the red or toward the blue end of the visible spectrum? Give a brief reason.