Questions tagged [charge]
A fundamental property of matter which causes it to experience electromagnetic forces.
3,264
questions
0
votes
1
answer
28
views
Infinite electrostatic plate acceleration
So, let's assume you have an infinite charged plate of some charge density, and a like-charged test charge positioned near it. In this case, the test charge is accelerated away from the plate at a ...
0
votes
0
answers
33
views
Let's say I add +2 and +4 micro coulombs of charge on a 1micro farad parallel plate capacitor. How would the charges be distributed?
I have been learning capacitors and I came across this problem where we are adding some charges to a parallel plate capacitor as mentioned above. I have no idea on how charges would be distributed ...
- 15
0
votes
1
answer
51
views
How to determine the charge of a $W$ boson in a Feynman diagram?
As the title says, I am not sure in what situations there is a W$^+$ boson and when there is a W$^-$ boson. My lecturer explained to me that you can view it either as the $W$ boson supplying a charge ...
- 1
1
vote
1
answer
59
views
Why is the potential due to induced charges constant?
Over the past few days, I have taken the time to read this interesting paper, where an unexpected counterexample is given that shows how the electrostatic force between a neutral metal conductor and a ...
- 359
1
vote
0
answers
54
views
In Peskin & Schroeder's QFT book page 704, the definition of electric charge is opposite?
In Peskin's book Chapter 4, the QED Lagrangian in Eq.(4.3) which contains the interaction term $$\mathcal{L}_{\mathrm{int}}=-q\bar{\psi}\gamma^\mu\psi A_{\mu}\tag{4.3}.$$ From this Lagrangian we can ...
- 11
-1
votes
0
answers
34
views
How, in induction of electric charges, the field developed due to separation of charges exactly cancels out the external field?
I have been learning electrostatics, and I didn't quite understand why charges reside only on the surface. The charges are moved until they reach the surface after which they cannot move further and ...
- 15
1
vote
0
answers
10
views
On which atomic factors of the materials does the phenomena of static charge depends?
Please correct me if I am wrong. Almost all materials are made up of atoms with electrons.
If we rub two different materials, like plastic scale and oily hair on the head, then static charge develops ...
-5
votes
1
answer
72
views
How charge interact with mass? [closed]
If mass does not interact with charge, why does the mass of an electron move (means by which mechanism it moves) in an electromagnetic field? It is same like we stick ball on magnet with fevistic and ...
1
vote
1
answer
44
views
Increasing order of charge/mass ratio for electron, proton, alpha-particle and neutron [closed]
So there is this question where we have to arrange the charge by mass ratio of the aforementioned particles/ions.
So I googled for the answer and in most of the places the answer is given as:
n < α ...
- 13
-1
votes
0
answers
44
views
Electrical charges and energy
Since we have defined energy as the ability to do work, how come electric charges (-) and (+) be able to do work without using any energy? If lets say I have a big fixed positive charge and if lets ...
- 1
0
votes
1
answer
39
views
Why doesn't the frequency of a cyclotron make an impact on the radius of the path of a charged particle?
The cyclotron frequency is given by $$f=\frac{qB}{2πm}$$
Obviously this equation has nothing to do with the radius.
But my question is, when the frequency increases, shouldn't the velocity increase, ...
- 47
0
votes
0
answers
26
views
Variance of Capacitance
I'm studying Capacitance as a high school student and I have come across few things which I am puzzled about.
I understand that bringing a negatively charged conductor near a positively charged one ...
- 1
0
votes
1
answer
15
views
What happens to the potential difference and charge of a capacitor with dielectric if a battery is disconnected?
if I have a capacitor connected to a battery of 12V and it has 3C of charge and I add a dielectric let's say $q$ would increase to 6C and $ΔV$ would remain constant. Now I'll disconnect the battery, ...
- 11
0
votes
2
answers
44
views
Decreasing of a charge amount and its effects on a capacitor
There is an equation of charge amount on a capacitor you may know;
This graph above shows the charge amount. And according to the book "Fundamentals of Electric Circuit from CK Alexander", ...
3
votes
1
answer
87
views
Quantization of charge from the path integral
Consider a complex scalar field, with the usual Lagrangian:
$$
\mathcal{L} = | \partial_{\mu} \phi|^2 - V(|\phi|^2).
$$
This theory has a $U(1)$ symmetry, $\phi \to e^{i \alpha} \phi$, and the ...
- 2,848
1
vote
1
answer
74
views
Why don’t charge carriers constantly accelerate in an electric circuit?
With my current knowledge of electric circuits and electrostatic fields, I would expect that the electric field generated by the potential difference of, say, a cell should exert a constant force upon ...
- 195
0
votes
0
answers
43
views
What sort of QED-like theories can have non-quantized charge?
It is often said that the existence of a single monopole would force electric charge to be quantized, due to Dirac's argument. However, one can write down theories like QED that, independently of the ...
- 748
0
votes
1
answer
57
views
Is the superconducting wire in a equilibrium DC circuit free of surface charge?
Suppose we have a closed circuit composed of a time constant voltage battery, a resistor and superconducting wires connecting them in series. In the equilibrium state, both the free charge the ...
- 941
1
vote
0
answers
26
views
Does fixed charge inside the dielectric of a parallel plate capacitor change the overall capacitance value?
The capacitance for a parallel plate capacitor with surface area $A$ separated by a distance $d$ with a dielectric placed between the plates of value $\epsilon$ is expressed as:
$$C=\frac{q}{V}=\frac{\...
- 123
1
vote
2
answers
87
views
Are two oppositely charged black holes, matter & antimatter?
Let's say we have 2 identical black holes, except that their charges are opposite in sign.
Can we consider one to be matter, and the other antimatter? After all, I heard that anti-particles are the ...
- 2,959
0
votes
0
answers
18
views
What is the proper term for the linear, surface area, and volume components in density equations?
Say one is looking at charge density. Linear charge density would be given by
$$
\lambda = \frac Q \ell
$$
surface charge density would by given by
$$
\sigma = \frac Q A
$$
and volume charge density ...
- 329
4
votes
1
answer
533
views
How is Law of Conservation of Charge valid if protons and electrons are destroyed in a system?
So I am preparing for an exam with material from openstax books on physics. There in the static electricity chapter I saw this paragraph,
"Because the fundamental positive and negative units of ...
- 53
1
vote
0
answers
15
views
How to know which formula to use for the electric field of a conducting plate of charge? $𝐸=σ/2ε_0$ or $𝐸=σ/ε_0$? [duplicate]
I'm so confused right now as I have come across questions regarding the E.F of a conducting plate of charge.However some questions use 𝐸=σ/2ε0 whereas others use 𝐸=σ/ε0 and I genuinely don't know ...
- 11
0
votes
0
answers
29
views
Does a d'Arsonval coil / Oudin coil / "violet ray" electrotherapy device produce a complete circuit?
A few different historical designs exist for "medical" devices that generate a high-frequency oscillating voltage at the open end of a resonator circuit. Solid-state versions are sold on ...
- 1
2
votes
1
answer
81
views
About variational principles
Is there any way one can modify a known functional so as to get a solution for another quantity related to it? Because this is too general I would like to make it more clear with an example. Given the ...
- 29
0
votes
1
answer
20
views
Why my DC thick charging cable is slower than a thinner one? (having same power rating & adaptor)
Does that means thick wire cause more current loss than thinner one?
- 95
0
votes
0
answers
27
views
Non-standard circuit
I partially solved this problem.
Problem: A charged sphere of radius $a$ is connected through a resistance $R$ to the earth. An electronic flow breaks out towards the sphere of infinity at speed $v$ ...
0
votes
0
answers
49
views
Electrostatic: do Electrons really go away?
So imagine the classic science experiment where you take an empty aluminium can and a rubber bar that you charge with fur.
At first, that can is electrically neutral.
Two different cases now that I ...
- 1
2
votes
2
answers
79
views
Total bound charge equal to zero (proof)
I always see the assumption that the total bound charge is always zero, but is it not clear for me why is it true for every dielectric material, and I haven't find it in a textbook.
I know that $\...
1
vote
2
answers
85
views
Is the charge concept only applicable to electrostatics?
In an article of wikipedia, it is stated that :
Charge is the fundamental property of matter that exhibits electrostatic attraction or repulsion in the presence of other matter with charge.
I can't ...
- 59
0
votes
1
answer
42
views
When electrons go to the outside surface of a conductor why doesn't that create an electric field pointing radially outwards? $E$ is supposed to be 0
If an isolated conductor has a net zero charge and is not in an external field, would the free charges still move to the surface of the conductor eg. a conducting sphere? Wouldn't this create an ...
- 150
0
votes
3
answers
82
views
Why does the capacitance of a parallel plate capacitor increase on filling it with an insulating dielectric if the voltage is fixed?
In the case that the electric field $\textbf{E}_0$ is confined to the space between the plates of an isolated and charged parallel-plate capacitor, an inserted linear dielectric that fills the space ...
- 3,200
-2
votes
1
answer
58
views
In what media has the electric charge of an electron been measured? [closed]
I need specific references of experiments that have measured the electric charge of an electron in different media (water, air, others). I have found some performed in air or vacuum (Millikan, Thomson,...
- 105
0
votes
0
answers
47
views
What exactly is charge and what does it have to do with anything? [duplicate]
Often charge is defined as a measure of interaction with the electromagnetic field. However, electromagnetic field is often defined as a field produced by moving electrical charges, or relates to ...
1
vote
1
answer
54
views
Validity of coulombs law for a charge in motion [duplicate]
If there is a charge $Q$ kept firmly at rest and another charge $q$ is brought in the vicinity of $q$,it's obvious that $q$ will accelerate towards $Q$. Now,when we say that coulombs law is not ...
- 341
-2
votes
1
answer
110
views
Can you have a charge of 0 C?
Would it be correct to say that the neutron (for instance) has charge $0\ \rm C$?
Or can you have only positive or negative charges?
- 65
2
votes
1
answer
29
views
Dipole formation in electrostatic induction
Let's bring a positively charged rod near a conductor. Now since some electrons in outer shells are not strongly bound to atoms,they will get to the side near the rod. But why does it mean that dipole ...
- 341
1
vote
0
answers
68
views
Charge distribution on an infinitesimally thin, elliptical conducting thread
Assume an elliptical conducting thread, which is positively charged. Although the thread is considered to be very thin, its stiffness is great enough in order not to allow the Coulomb's forces between ...
- 2,491
1
vote
2
answers
31
views
Static condition of surface charges
We know that when charge is supplied to a conductor,they rearrange themselves on the surface thus making a static equilibrium condition. Let's suppose we have $+2e$ charge on a plane sheet conductor. ...
- 341
2
votes
3
answers
628
views
Understanding Maxwell's equations as opposed to high-school physics [closed]
I am currently learning university-level electromagnetism and have a problem arranging that with pre-existing school-knowledge. Unfortunately, the books I looked into so far simply introduce the ...
- 121
2
votes
1
answer
87
views
Does quantum field theory forbid spin-2 gravitons from carrying a charge that would make them repel each other increasingly with decreasing distance? [closed]
Can repulsive gravitons account for why gravity is weak compared to other forces and would they stop singularities from forming?
user381695
1
vote
0
answers
16
views
How to Compute the charge $Q$ of a particular state in free Dirac field? [closed]
For a free Dirac field, how can I explicitly compute the charge $Q$ of the state $a_{p1}^{r \dagger}a_{p2}^{s \dagger} b_{p3}^{t \dagger}|0>$.
The operator $Q$ is :
\begin{equation}
Q = \int \frac{...
- 43
1
vote
1
answer
53
views
Total energy stored on series capacitor with trapped charge
Suppose I have two capacitors in series, but with an initial trapped charge $Q_0$ between both capacitors.
What will be the total electrostatic energy stored on the system if we apply a voltage $V_g$ ...
- 1,012
2
votes
1
answer
28
views
Would a perfect plate capacity discharge if short-circuited by wires connected outside the $E$-field and why?
For a perfect plate capacity the $E$-field would only exist between the two plates. If I now connect an wire to both plates from outside, no $E$-field would "motivate" the charges to ...
- 141
0
votes
1
answer
58
views
Why small particles are attracted by charged objects?
Everyone knows this experiment: You mix salt and pepper and use a charged balloon to separate the pepper from the salt.
I never really understood how this works. In school (long time ago) we learned ...
- 101
-1
votes
2
answers
58
views
How much voltage would be required for a charge to have 1 amp of current with 0 resistance?
Voltage is the energy a charge has. If a charge has some energy it will move forwards. Resistance opposes the charge and it moves slower.
But what if resistance was exactly 0.
1--->How much voltage ...
- 11
1
vote
2
answers
70
views
Is Coulomb written/found on any object/product as its unit?
Today I had physics class and the unit Coulomb made me wonder as to why it was even invented when I don't see it being used anywhere. When I asked where it may be shown just like bulbs have x Watts ...
- 21
8
votes
3
answers
4k
views
What is the most highly charged celestial body in the universe?
Generally speaking, the universe is electrically neutral and
the universe abhors an unbalanced charge.
Wherever there is a positively charged object, you can bet there is a negatively charged object ...
-2
votes
1
answer
97
views
Does Ohm's law apply to a charge moving through empty space?
Clarification: I was playing with this idea and I thought of a scenario in which made me think Ohm's law might be incomplete. I will try to be as straightforward as possible. I am asking if the Ohm's ...
0
votes
1
answer
56
views
Quantum probability density of a uniformly accelerating charge [closed]
Is the charge probability density of a uniformly accelerating charge any different than one that isn’t?
- 129