In this applet, we can see the three main radiation laws in
graphic action. The main parameter in these radiation laws is the
temperature. It is indicated by the red column in the thermometer on
the right side, and you can change it by clicking and/or dragging on
it with you mouse.
- The main graph is the intensity of the radiation of the
blackbody as a function of the wavelength, l,
for the temperature selected. This graph (red curve) represents
the Planck radiation formula. For the visible wavelengths, we have
indicated the colors in this graph.
- You can also observe the shift of the peak location in this
graph with temperature. The wavelength for which the intensity is
maximum, lmax, is inversly
proportional to the temperature. This is known as Wien's law.
- The small inset is a graph of the total power, P, radiated.
For blackbody radiation, this is only a function of the
temperature. The gray line represents this radiation law, also
knows as the Stefan-Boltzmann law. The red dot marks the power
radiated for the current value of the temperature.
© W. Bauer, 1999