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Q & A: microwaves

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Most recent answer: 10/22/2007
Q:
According to some data I have heard, I belive the magnetic dipole moment of water is somewhere around 2.4 ghz, hence the principle of the mircowave oven. How does this relate to the 2.4ghz frequency used on cordless telephones and on wi-fi equipment? Are these devices harmful?
- Jonathan (age 18)
Arizona
A:
I think what you must have heard is that water does a good job of absorbing radiation whose frequency is 2.4 GHz. The main way it absorbs the radiation is by the wiggling of the water molecules' electrical dipoles by the electrical field of the radiation. Magnetic effects really don't have anything to do with it.


Since we're mostly made of water, we must absorb some energy from devices emitting microwaves. Obviously, that can make serious problems if some part of you gets too hot. So far as I know, there's no good evidence of dangers from various devices like the ones you mention, and no known likely mechanism for such danger. Of course, biology can have some tricky surprises.

For a while, there was much talk of danger from low-frequency fields from power lines. The power line question has been investigated very thoroughly now, and it's clear that any danger is either extremely small or zero.

Mike W.

(published on 10/22/2007)

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