this is a duplicate of this question but I came away not understanding the answer, even after reading the links.

so my question is: how does light increase the heat energy of an atom?

eg. if you have a lens and you focus a lot of light into a point you can get a fire, what is the science behind the fire-from-light part of this

  • $\begingroup$ Not sure I understand the question. You state Kinetic Energy in the title but Heat Energy in the text. Are you asking about heating up a large collection of atoms or imparting kinetic energy to a single particle at the quantum level? $\endgroup$ – ggcg Jan 28 '19 at 1:13
  • $\begingroup$ @Ryan Bright The answer to the question for which yours is a duplicate, is very clear. There is no single dominant mechanism which transfers the energy of a photon absorbed by a single atom into its kinetic energy. $\endgroup$ – Dr S T Lakshmikumar Jan 28 '19 at 2:21
  • $\begingroup$ @ggcg sorry I mean heat energy, I will edit $\endgroup$ – Ryan Bright Jan 28 '19 at 6:15
  • $\begingroup$ @DrSTLakshmikumar, you say there is no single dominant mechanism... But it is worth documenting the mechanisms and explaining them. Certainly there is some mechanism at work, scattering, etc. $\endgroup$ – ggcg Jan 28 '19 at 13:37
  • $\begingroup$ @ggcg the answer given to the "duplicate" question is quite comprehensive. I saw no reason to copy or paraphrase $\endgroup$ – Dr S T Lakshmikumar Jan 29 '19 at 14:06

Light is an electromagnetic wave, which you can think of as vibrations in the electromagnetic field in space. When a vibrating electric field reaches a charged particle, such as those in an atom, it exerts back-and-forth forces on the particles, causing them to move and oscillate repeatedly at the frequency of the light. This movement is kinetic energy. An increase in the collective kinetic energy of molecules corresponds to increased temperature, and given a sufficiently large increase, you can create a fire under usual conditions.


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