A 100-W incandescent light bulb bas a cylindrical tungsten filament 30.0cm long, 0.40 mm in diameter, and with an emissivity of 0.26.
(a) What is the temperature of the filament?
(b) For what wavelength does the spectral emittance of the bulb peak?
(c) Incandescent light bulbs are not very efficient sources of visible light. Explain why this is so.