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Why do black objects absorb more heat (light) than lighter colored objects? What do wavelengths have to do with it?
Question Date: 2013-03-18
Answer 1:

Heat and light are both different types of energy. Light energy can be converted into heat energy. A black object absorbs all wavelengths of light and converts them into heat, so the object gets warm. A white object reflects all wavelengths of light, so the light is not converted into heat and the temperature of the object does not increase noticeably.

Different wavelengths (colors) of light have different amounts of energy. Violet light has more energy than red light. If we compare an object that absorbs violet light with an object that absorbs the same number of photons (particles of light) of red light, then the object that absorbs violet light will absorb more heat than the object that absorbs red light.

The amount of heat absorbed is also affected by how light or dark an object is. A dark object of a given color will absorb more photons than a light object of the same color, so it will absorb more heat and get warmer.

Note about how the color of an object appears: The color an object appears is the complementary color to the color the object absorbs. If an object absorbs yellow light, then it will reflect all of the other colors of light and it will look purple.

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