Evaluation of the Planck blackbody equation. Demonstrates how the emission spectrum of a blackbody radiator depends on its temperature and emissivity.
This model can be used to determine whether a light source has a blackbody-like emission spectrum and to estimate its temperature and emissivity if so. Students take experimental measurements of the radiance of a light source at various wavelengths, type in the values of wavelength and radiance into the table on the right, then adjust the parameters of the model (temperature and emissivity) so that the calculated blackbody spectrum (shown by the red line) is a best fit to the experimental data points (shown by the blue dots).
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WingZ version: black.wkz; Screen image.
Wingz player application and basic set of simulation modules, for windows PCs or Macintosh
Other simulations that
employ a blackbody source:
Signal-to-Noise Ratio of Absorption Spectrophotometry
Fluorescence Spectroscopy Signal-to-Noise Ratio
Dual Wavelength Spectrophotometer
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Blackbody temperature, T (in degrees K), set by on-screen slider.
Emissivity, set by on-screen slider.
Calculated radiance = emissivity*1.19111E+16*wavelength^(-5)/(exp(14380000/(wavelength*T))-1)
The graph shows a plot of calculated radiance (red line) and measured radiance (blue dots)
Computes the spectral radiance, total radiance, and peak wavelength of a blackbody source, given the temperature and emissivity. Also plots spectral radiance vs wavelength from 150 nm to 3500 nm.
Note: to run the OpenOffice
(.ods) spreadsheets, you have to first download the OpenOffice
then install it (by double-clicking on the installer file that you
downloaded), and then download my spreadsheets from this page.
Once OpenOffice is installed, you can run my spreadsheets
double-clicking on them.