Radiation Curves
Continuous Radiation How bright is the continuous spectrum at different colors? How does a perfect light source emit its light? 400nm 500nm 600nm 700nm
Early Experiments Darken inside with carbon black Measure radiation that emerges from hole Blackbody Radiation
Vis IR UV
Changes with Temperature * Visible 5000 K 6000 K 7000 K * *
Wien’s Displacement Law The wavelength of the peak of the blackbody curve is inversely proportional to the temperature. Cool stars are red - hot stars are blue Wilhelm Wien
Total Energy
Stefan-Boltzmann Law Area under the blackbody curve measures the total energy output of the source and is proportional to T 4. Josef Stefan Ludwig Boltzmann
Blackbody Radiation Everything in nature emits light The type of light emitted depends on the temperature of the source The walls of this room IR Stars Visible and UV The Corona of the Sun (2,000,000 K) X-rays
ORION
Some Real Stars Rigel K Sirius A K The Sun 5800 K
More Real Stars The Sun 5800 K Capell a 5200 K Betelgeuse 3600 K
Review Animation
Two-Dimensional Spectra Continuous Emission Absorption
Visible Light Infrared Light The Orion Nebula