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Q & A: What happens to light energy?

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Most recent answer: 07/17/2012
Q:
it is said that objects absorb a certain frequency of light and reflect other that is why we see 'color' of the object. but since it is an energy so what does happen of the color absorbed in object? is it transformed into some other form according to law of conservation of energy?
- puneet (age 21)
edison, new jersey, usa
A:
Yes, the light energy usually initially goes into raising some electrons from low-energy states to high-energy states. What happens next depends on the material. Often the electrons settle down, dumping their energy as heat, just thermal shaking of the atoms in the material. It gets warmer. Of course, on a sunny day, you feel exactly that. Some of the energy can also go into forming new chemicals, more or less long-lasting. I'm wearing photochromic glasses, in which light causes chemical reactions that make more absorbent chemicals, temporarily turning them into dark glasses in bright light.

Mike W.

(published on 07/17/2012)

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