Three identical metal spheres are heated until each glows brightly
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Modern Physics · Modern Physics
Problem
Three identical metal spheres are heated until each glows brightly. An infrared camera records the wavelength at which the emitted intensity from each sphere reaches a maximum. The recorded peak wavelengths are listed below.
• Sphere 1: λpeak=9μm
• Sphere 2: λpeak=5μm
• Sphere 3: λpeak=1μm
Each sphere acts as a perfect blackbody.
(a) Rank the spheres in order of decreasing surface temperature. Clearly indicate which sphere is hottest and which is coolest, and justify your ranking without performing explicit numerical calculations.
(b) Explain how the shape of the intensity–wavelength curve for Sphere 3 would compare to that for Sphere 1 in the visible portion of the spectrum. Your explanation should reference the physical connection between temperature and the distribution of emitted wavelengths.