It is always known that electrons and protons have opposite charges but what gives electrons or protons the charges they have?
26326
Baryons have charges that are the result of a polynomial calculation of their building blocks (quarks)'s fractional charges. But what gives these quarks electric charges? What interactions do they have with photons? And what about leptons, like muons and electrons? How do they get their -1 charge? And then, how do positrons and anti-muons get +1 charge? Same goes for quarks: how does up-antiquarks get -2/3 charge? Or I may want to formulate my question this way:  How does any elementary particle interact with the EM-Force to get an electric charge?
18642
A man asked me this question in suburban train when I told him that I am an electrical engineer. Of course I replied him that current is the flow of electrons and in order for the current to flow there should be a potential difference between them. But the man didn't know what electron or potential difference was either.
13328
How do these particles exchange information about charge and position between themselves, even though there's mostly empty space between them?  Also what happens if a free electron passes closer to a nucleus of a hydrogen atom than its own electron?   My random guesses so far:   Proton won't react because it's somehow locked with its existing electron Proton will catch it and release the previous one  Proton will catch it and keep both of them with half the force Existing electron will simply repel incoming one Something else?
40793
Do the protons inside the nucleus repel each other by the electrostatic force? If they do, why doesn't the repulsion drive the protons apart so that the nuclei get disintegrated?
75454
For historical reasons, I understand that a proton's charge was assigned the label of "positive", the electron's charge was assigned the label of negative, and, crucially, equations of current in E &amp; M are written with the notion that current is the flow of positive charge despite the rarity of actual flows of protons in real systems (which I understand are mostly biological systems).   If the possibility existed to instantaneously and at no cost, retcon these associations such that protons have a negative charge, electrons have a positive charge, and current remains the flow of positive charge, would there be any beneficial or detrimental outcomes?  For instance, would there be:   new interpretations of physical laws that would provide different or better insights into any relevant subfield of Physics significant simplifications to notation in any field of Physics or Engineering significant increases in understanding in the fields of electricity, electronics, electrical engineering, radiation/radiative transport, etc. a noticeably easier learning curve for any subfield of physics dealing with the concept of charge   Additionally, is there a permutation of positive charge, negative charge, and flow of current definition that would improve upon the one I suggested?
15282
We all learn in grade school that electrons are negatively-charged particles that inhabit the space around the nucleus of an atom, that protons are positively-charged and are embedded within the nucleus along with neutrons, which have no charge. I have read a little about electron orbitals and some of the quantum mechanics behind why electrons only occupy certain energy levels. However...  How does the electromagnetic force work in maintaining the positions of the electrons? Since positive and negative charges attract each other, why is it that the electrons don't collide with the protons in the nucleus? Are there ever instances where electrons and protons do collide, and, if so, what occurs?
110430
I know that when there are excess positive charges in a conductor, for example, a metal sphere, the positive charges will spread out over its surface. However, I am confused about how this excess charge spreads out over the surface, if protons cannot move and only electrons can move. Can someone please inform me on how the excess positive charge spreads out over the surfaces of conductors?
76877
How can it be that, if like charges repel, they don't repel themselves? In other words, why don't charges break apart?  About the possible duplicate: I want to know about charges in general, not just that of an electron. My response to :  Thank you very much for the extensive explanation. Unfortunately it's a bit above my level (I'm a first year electrical engineering bachelor student). This is how I understand it: If the charge is the sum of multiple separate charges, there has to be an external force that keeps this charges together. However we most often think of electrons and protons as point charges. In other words, we don't think of them as if they are made up from different (smaller) parts. But the idea of electrons and protons as point charges has its own problems. I didn't know that the electric field has a mass. From the formula, I understand that $m\propto \frac{1}{r}$. This would mean that $m\rightarrow \infty$ as $r \rightarrow 0$ (or $r = 0$), which of course is physically not possible. But there is a way to calculate the radius of an electron based on the mass, the speed of light and the constant of Planck. (Unfortunately I don't know why.) You can get around this by a technique called called renormalization, which causes the integral to converge. Unfortunately, I don't understand the rest of the answer due to my level in physics. Nevertheless I am grateful for you answer. It would be awesome if you could confirm or correct my understanding.
72447
When Dirac found his equation for the electron $(-i\gamma^\mu\partial_\mu+m)\psi=0$ he famously discovered that it had negative energy solutions. In order to solve the problem of the stability of the ground state of the electron he invoked Pauli's exclusion principle and postulated that negative energy states well already filled by a "sea" of electrons. This allowed him to predict the positron, viewed as a hole in the sea.  This interpretation was ultimately discarded owing to its inapplicability to bosons and difficulties with explaining the invisibility of the infinite charge of the sea.  According to my understanding, the modern argument goes something like this. There is a discrete symmetry of the lagrangian called charge conjugation $\psi \rightarrow \psi^c$ which allows the negative energy solutions to be interpreted as positive energy solutions for a second mode of excitation of the electron field with opposite charge, called positrons. The decay of electrons to positrons is then suppressed by the $U(1)$ gauge symmetry of the lagrangian forcing conservation of electrical charge.  According to this interpretation What Dirac would have missed was the lagrangian formalism. Is this historically and physically correct?
12742
Do all planets have an electric charge?   If yes, is positive or negative?  And how much each magnitude?   I have read some articles which really confused me. Some of these articles said that all planets have a negative charge and the sun has a positive charge. Some other articles said the the exact opposite.
85057
Is it an accurate statement to say that free electrons in a metal experience NO restoring force when they interact with electromagnetic waves? I understand that the electrons exist in a space filled with ions, and doesn't the cumulative potential that is present due to the presence of the ions exert an electric field on the electrons. Even in the case of simple metals, where you can say that the nucleus is shielded by the valence electrons, so called Coulomb shielding, how significant is the shielding. Naively, it seems to me that because the charge in the nucleus is not balanced by the charge in the bound electrons, there should be some net potential that the free electron sees.
33024
I read this in my textbook: A charged particle or object is not affected by its own electric field.  Since I find this completely unintuitive and my mind is yelling "wrong! wrong! how could a particle even distinguish between its own field and the external fields?" I would really like to hear an explanation about why this is true, if it is.  (A corollary question that comes to my mind after thinking about this is... What about gravity and mass considering the analogous situation? And the other two forces?)
90443
Electrons belong to a group of elementary particles called leptons. There are charged and neutral leptons. And electron is the charged one. But how come it got charged?  The negative or positive charges were assigned by convention. But it is a fact that electrons are charged. My question is why electrons? and not neutrons?  Also while reading , I saw that "Independent electrons moving in vacuum are termed free electrons. Electrons in metals also behave as if they were free. In reality the particles that are commonly termed electrons in metals and other solids are quasi electrons, quasiparticles, which have the same electrical charge, spin and magnetic moment as real electrons but may have a different mass  ( or Effective mass - extra mass that a particle seems to have while interacting with some force )."  What does this mean?
28449
As I understand these two statements:   An electromagnetic field gives particles charge A photon is a quantum of electromagnetic field   It must mean that a photon carries charge. But I guess it isn't true. Why not?
65426
Sometimes we see energy that is negative, for example, the energy of an electron in orbit. We know energy is something that can do something. In this view does negative energy mean something opposite someway?
45240
So atoms are formed from protons and neutrons, which are formed from quarks.  But where do these quarks come from? What makes them?
2651
What is the explanation between equality of proton and electron charges (up to a sign)? This is connected to the gauge invariance and renormalization of charge is connected to the renormalization of photon field, but is this explanation enough? Do we have some experimental evidence that quarks have 2/3 and -1/3 charges? By the way I think about bare charge of electron and proton. And I am also wondering if this can be explained by Standard Model.