6
$\begingroup$

As far as I know, Electric and Magnetic interactions are dependent on the charge a body carries. How do particles that have no net charge, interact with EM radiation?

Edit : As suggested by an answer, EM radiation( through photons, ofc) has its effects on the charged fundamental constituents of the atom. Does this imply that neutrons won't have any interaction with light? I also know that they are made of quarks that have a partial $e$ charge, but they are very densely packed together. What would happen then?

$\endgroup$
  • 3
    $\begingroup$ Do you mean neutral particles (e.g. neutrons) or particles with no net charge (e.g. dust)? A water molecule is neutral but still has a dipole moment, and hence can interact with light. $\endgroup$ – ahemmetter Apr 5 at 10:05
  • 1
    $\begingroup$ dupe? Which elementary particles does light interact with? $\endgroup$ – J... Apr 5 at 13:14
6
$\begingroup$

All matter we observe around us is composed by atoms and molecules, and atoms and molecules are composed of elementary particles , seen in this table, where the photon is a part of.

The classical electromagnetic light, at the particle level, emerges from a superposition of zillions of photons. Photons interact with the electromagnetic interaction with the electrons around the nuclei of the atoms and with the collective spill over electric and magnetic fields of solids, liquids and gases. Matter may be macroscopically neutral, but the photons which compose a light beam can interact at the particle level of the components of matter. Thus a wall ( or a mirror) is neutral, but light reflects from the wall(mirror), the photons of light scattering from the wall(mirror) at the level of the constituent particles and the topology of their electric and magnetic fields.

Does this imply that neutrons won't have any interaction with light

Neutrons as you observe, are composed of quarks, which as quantum mechanical point elementary particles have a wavefunction. There will always be a probability for a photon to interact with a quark through the electromagnetic coupling, particularly a high energy one. There will be similar diagrams with quark loops as shown in my answer here.

$\endgroup$
  • $\begingroup$ When you say that photons interact with the charged constituent particles of bulk matter, are you referring to electrons and protons, or quarks? If the former, would that mean that photons are noninteractive with eg neutronium? $\endgroup$ – kevinsa5 Apr 5 at 13:53
  • $\begingroup$ I have added something to my question. I would request a clarification of that as well, since this has sprouted from the very explanation of yours. $\endgroup$ – Aabesh Ghosh Apr 5 at 13:59

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.