Ask A Scientist Physics Archive

name         Pragya N.
status       educator
age          40s

Question -   How is reflection of an electro-magnetic wave
different from refraction at atomic level?
How does an atom decide to reflect and / or refract an
electro-magnetic wave of a particular frequency?
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Hi, Pragya !!!

Good question...But, take into consideration
that a metal reflects electromagnetic waves
because of its free electrons. Non metals have
NOT this property, and then comes into action
the refraction, although part of it is reflected.
The refraction occurs owing to interference
between both electromagnetic fields of the
material under observation AND the wave
electromagnetic field.

Regards

Alcir Grohmann
Beschaffung SAM
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Pragya N.

At an atomic level, reflection and refraction are exactly the same.  A
photon is absorbed, held for a moment, and then the energy is released as
another photon, in a fairly random direction.  Refraction occurs when many
photons released from many atoms in a forward direction interfere
constructively, working together to make a beam bright enough to stimulate
your eye.  Reflection happens when the constructive interference is in the
backward direction.  Photons in other directions are usually identified as
heat emitted in the form of radiation:  energy is lost, but not in high
enough intensities to stimulate visual instruments.

Dr. Ken Mellendorf
Illinois Central College
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