Solar Radiation, Peak Temperature, Heschel's Experiment
If the sun´s spectrum peaks in the
green-yellow, why the measurement of the
temperature of the projected spectrum gives the
higher temperature in the infrared (Heschel´s experiment)?
The infrared wavelengths of light are absorbed by most targets, so its
energy is converted into vibrations of the target (heat). There are many
variations on this principle. For example, a black target (e.g. sheet of
paper) gets warmer faster than a white sheet of paper because the black
sheet of paper absorbs all wavelengths of light and a white sheet of paper
absorbs very little. It reflects most, while the black sheet reflects almost
none. Once absorbed, the visible light is converted by a number of
mechanisms into heat.
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Update: June 2012