Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: chris on 22/06/2008 23:27:03

Title: Would a strong magnet placed behind a mirror affect the reflected image?
Post by: chris on 22/06/2008 23:27:03
Since light is an electromagnetic wave which has to interact with the atoms on a silvered surface of a mirror in order to be reflected, would placing a powerful magnet behind a mirror alter the reflection?

Chris
Title: Would a strong magnet placed behind a mirror affect the reflected image?
Post by: RD on 23/06/2008 11:04:22
Quote
Magneto-optic Kerr effect*...
The light that is reflected from a magnetized surface can change in both polarization and reflectivity.
http://en.wikipedia.org/wiki/Magneto-optic_Kerr_effect

Possibly the Zeeman effect could change the spectrum of the reflected light, (not sure though).
http://en.wikipedia.org/wiki/Zeeman_effect

[*there is also the Kerr electro-optic effect, which is used modulate laser light (electro-optic shutter)
http://en.wikipedia.org/wiki/Kerr_effect]     
 
Title: Would a strong magnet placed behind a mirror affect the reflected image?
Post by: daveshorts on 25/06/2008 10:19:54
The Zeeman effect is an effect on the energy levels in an atom - if you have two electrons in the same orbital, as they are orbiting they are a bit like two magnets. If you then apply a magnetic field the one orbiting so its spin is in line with the field will have a lower energy and the one aligned the other way will gain magnetic potential energy so be at a higher level.

You can see the consequences of this in emission lines, and acting on nuclei it is the basis of NMR/MRI
Title: Would a strong magnet placed behind a mirror affect the reflected image?
Post by: lightarrow on 25/06/2008 13:38:17
Since light is an electromagnetic wave which has to interact with the atoms on a silvered surface of a mirror in order to be reflected, would placing a powerful magnet behind a mirror alter the reflection?
If it changes, because of the effects already described in the previous post, the change would be extremely small; remember that light is an electromagnetic wave, that is electric and magnetic fields vary very fast in time; with a constant and uniform (at least with respect wavelenght) magnetic field, even if is very strong, you don't vary the wave's parameters.
Title: Would a strong magnet placed behind a mirror affect the reflected image?
Post by: Bored chemist on 25/06/2008 18:11:45
The direct effect of the magnetic field will be near zero- probably too small to detect.
My guess (and it's no more than that) is that the diamagnetic repulsion of a typical mirror might bend it enough to distort the image more than the Kerr effect distorts it (depends how thin the mirror is, with a thin enough silver foil the repulsion will dominate).
Title: Would a strong magnet placed behind a mirror affect the reflected image?
Post by: Kryptid on 26/06/2008 19:26:56
I've read that in a very intense magnetic field, photon splitting may occur. In essence, a photon of one energy is split into two photons with half the original energy each. If that is the case, a sufficiently strong magnetic field could alter the colors in a reflected image.