A laboratory furnace is used to heat three large metal plates
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A laboratory furnace is used to heat three large metal plates. Each plate radiates approximately as an ideal continuous emitter. Plate X is known to be at 1200K and its emission spectrum peaks at 2400nm. Two additional spectra, labeled Y and Z, are recorded under identical experimental conditions:
• Spectrum Y peaks at 1600nm and the area under its intensity curve is four times the area under spectrum X.
• Spectrum Z peaks at 1200nm and the area under its intensity curve is ten times the area under spectrum X.
(a) Determine the absolute temperature of plates Y and Z. Show all steps in your reasoning.
(b) For each plate, calculate the ratio of its power emitted per unit surface area to that of plate X.
(c) Assess whether the measured areas under spectra Y and Z are consistent with the temperature ratios you obtained in part (b). Clearly state any assumptions or approximations used.
(d) On a set of blank axes with the same scales as those described in the stimulus, sketch the qualitative shape of the spectrum that would correspond to a fourth plate whose spectrum has the same peak wavelength as plate X but one-half the total area. Explain the physical meaning of this new curve in terms of surface temperature and emitting area.