Austin R. Carter
Department of Physics, The College of Wooster Wooster, Ohio 44691, USA
(Dated: May 3, 2004)
Abstract
The tungsten filament of a light bulb was used in a thermal experiment as an approximate blackbody to verify the Stefan-Boltzmann law. The resistance of the filament at room temperature was measured to be 0.309±0.002 Ω. This was then used in conjunction with tabulated CRC resistivity values to calculate the temperature of the filament for different power inputs. Two analysis techniques were employed to confirm that the radiation from an object is proportional to the fourth power of its absolute temperature. The first method used a three parameter, fourth-order polynomial function and determined the proportionality constants σ As and kAo to be (5.80 ± 0.09) × 10−13( W K4 ) and (1.186±0.068)×10−3 ` W K ´ , respectively. The second method used a log-log plot of the inputed power as a function of the absolute temperature and determined σ As to be (6.32 ± 0.09) × 10−13( W K4 ) which is in agreement with the first method’s value to 3σ. The exponent was determined to be 4.00 ± 0.55 which strongly supports the Stefan-Boltzmann law.
To download the article click on the link below:
http://physics.wooster.edu/JrIS/Files/Carter.pdf
Department of Physics, The College of Wooster Wooster, Ohio 44691, USA
(Dated: May 3, 2004)
Abstract
The tungsten filament of a light bulb was used in a thermal experiment as an approximate blackbody to verify the Stefan-Boltzmann law. The resistance of the filament at room temperature was measured to be 0.309±0.002 Ω. This was then used in conjunction with tabulated CRC resistivity values to calculate the temperature of the filament for different power inputs. Two analysis techniques were employed to confirm that the radiation from an object is proportional to the fourth power of its absolute temperature. The first method used a three parameter, fourth-order polynomial function and determined the proportionality constants σ As and kAo to be (5.80 ± 0.09) × 10−13( W K4 ) and (1.186±0.068)×10−3 ` W K ´ , respectively. The second method used a log-log plot of the inputed power as a function of the absolute temperature and determined σ As to be (6.32 ± 0.09) × 10−13( W K4 ) which is in agreement with the first method’s value to 3σ. The exponent was determined to be 4.00 ± 0.55 which strongly supports the Stefan-Boltzmann law.
To download the article click on the link below:
http://physics.wooster.edu/JrIS/Files/Carter.pdf
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