The title is self-explanatory. I know that the electrons at the tip of Live get pushed in and out with respect to Neutral. (You shouldn't say there is no current; since there is air, a poor conductor, but still a conductor)

Does this back and forth motion of electrons cause emittance of photons at 50/60Hz? If so, assuming we have gained some 50/60Hz light-sensitive cells on our retina due to pure chance, don't you think it would be fun to see a glow around wall sockets and wouldn't you use it as a sleeping lamp?

  • $\begingroup$ You don't have to see it, because you can often hear it: en.wikipedia.org/wiki/Mains_hum $\endgroup$ – probably_someone Sep 11 at 19:00
  • $\begingroup$ No reason to think that the ends of the wire would radiate any more than anyplace else along the wire. (And note: The materials of which your walls, floors, and ceilings are made most likely are completely transparent to 50Hz "light.") The question is, do the wires in your walls have the right geometry to be an effective antenna at that frequency. I don't know much about antenna design, but here's some folks who know quite a lot: arrl.org/shop/ARRL-Antenna-Book-23rd-Softcover-Edition $\endgroup$ – Solomon Slow Sep 11 at 19:20
  • $\begingroup$ @SolomonSlow considering the wavelength of EM radiation at 50 Hz is about 6,000 km, unless your house is the size of a small planet the geometry of the wiring is fairly irrelevant to its efficiency as an antenna. $\endgroup$ – alephzero Sep 11 at 19:24
  • $\begingroup$ Normal sockets appear to lose way less than 1 W of power (since it is small compared to "vampiric" power losses from connected by standby or switched off devices). 1 W LEDs are definitely visible, and I suspect we could see 0.1 or even 0.01 W losses (we do see starlight after all, about 10^${-8}$ W/m$^2$). But 50 Hz eyes would need rather long photoreceptors - it is hard to get directionality at low frequency. $\endgroup$ – Anders Sandberg Sep 11 at 19:24
  • $\begingroup$ Maybe a different question worth asking: What would an "eye" look like if it was capable of forming a real image from "light" rays that had a wavelength of 6000 km. $\endgroup$ – Solomon Slow Sep 11 at 19:24

The problem isn't the socket, it's the eye. To answer directly, if the eye could see at 50 Hz, yep, you'd see it glowing. It appears that you can see single photons, on average, so the leakage from your wiring would be more than enough. But...

Very generally, to get reasonable "reception" you need an "antenna" that is resonant at the frequency in question. This is why old-school VHF TV antennas have multiple arms sticking out of them, each one is resonant at a different frequency so that it has broader frequency response. The shortest you can really go is about 1/4 the wavelength, although cell phones and such are often shorter.

Of course, human vision isn't based directly on little antennas but the visual receptor proteins like visual purple. These do have wavelength-sensitive structure which makes them relatively highly turned to specific frequencies. So then in order to see 50 Hz, you would need cones with a new visual protein in them.

Assuming that protein has something like a quarter-wave dipole structure, to be sensitive to 50 Hz it would have to be about 150 km long. The eyeball needed to hold that... well...

So, yes but no!


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.