2
$\begingroup$

I was looking at my microwave the other day and I thought that the metal mesh screen might be acting like a set of perpendicularly oriented polarizers. Other explanations I've heard on how this screen blocks out radiation seem to hinge on the wavelength of microwaves being large enough that the spacing of the mesh screen effectively looks like a solid screen to incoming microwaves. Is it accurate to think of the mesh screen like a set of polarizers? If not then could the metal mesh screen be replaced by a mesh of any arbitrary material and still block out radiation?

Improve this question
$\endgroup$
20
  • 1
    $\begingroup$ No. So then does that mean that the mesh screen doesn't necessarily need to be metal? Would a wooden mesh work just as well, or a glass mesh? I thought they might be polarizers because they looked like polarizers, but is that just coincedental? $\endgroup$
    – Phaidros
    Commented Jun 27, 2017 at 23:55
  • 1
    $\begingroup$ Metal is used because it reflects radiation. Wood or glass might absorb a tiny bit and reflect even less, but most would be transmitted (unless the wood is wet, then the water inside would absorb it). $\endgroup$
    – probably_someone
    Commented Jun 28, 2017 at 0:16
  • 1
    $\begingroup$ So then the metal mesh shields from radiation partly because it is reflective and partly because grid spacing is comparatively small for microwaves? $\endgroup$
    – Phaidros
    Commented Jun 28, 2017 at 0:22
  • 2
    $\begingroup$ Precisely. A metal sheet without holes would work just as well, but then you wouldn't be able to see inside. $\endgroup$
    – probably_someone
    Commented Jun 28, 2017 at 0:24
  • 1
    $\begingroup$ In order for a polarizer to work, the length of the grating (not the spacing between the slats, but the length of said slats) should be greater than the wavelength of the waves. The wavelength of microwaves in a microwave oven is roughly 12 cm. The openings in the mesh of a microwave are typically less than 1 cm on a side. So it is literally not possible for the mesh to act as a polarizer. $\endgroup$
    – probably_someone
    Commented Jun 28, 2017 at 1:44

0

Reset to default

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.