Applet: Blackbody Spectrum

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, l_max, 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.