3
votes
1answer
50 views

Acceleration of electric charges and radiation

According to classical electromagnetic theory, accelerated charges should emit radiation and lose energy. The reason given in my book why atoms don't emit radiation (say, when the atom moves along a ...
0
votes
0answers
23 views

Electrostatic pressure and charge [closed]

I've become a bit stuck on a question involving the charge transferred to a soap bubble as it's momentarilly connected to a potential V. I calculated the pressure difference between the atmosphere ...
0
votes
0answers
18 views

Question regarding 2 conducting spheres connected by a long fine line (electric potentional)

I'm having a bit of trouble understanding a pretty simple issue. Assuming I have 2 conducting spheres uniformly charged connected by a long fine line (as shows in the added photo) and im being asked ...
0
votes
0answers
27 views

What is the symmetry associated with electric charge conservation [duplicate]

Is there a kind of symmetry that yields the conservation of charges? and if so , how it works for both type of charges? Electrical Charges
3
votes
2answers
342 views

What is charge actually? How to define it? [closed]

Is charge of something for (e.g.) an electron related to electromagnetic space if it exists due to energy, due to which it may have mass? I don't know about quantum mechanics or advanced particle ...
0
votes
1answer
51 views

How does this particle behave in the magnetic field?

I have the above question and I have though about it every way and can't seem to find out. So what I have concluded (ignore the answers on the img) Is that the force is on the z axis because the ...
1
vote
0answers
54 views

About Divergence in polar coordinates

I've got a conductor in a cylinder shape who is rotating with angular velocity $\omega$ around its axis, that correspond to the $z$ azis I want to calculate the electric field and the density of ...
2
votes
1answer
79 views

What will happen if the charge do not exist? [closed]

It is just a naive idea, and I want some discussions to help me think deeper. I don't know the reason of indispensability of charge, maybe some physical laws guarantee that the charge must be exist. ...
1
vote
5answers
328 views

How would charge distribute if electrons were balls?

In a conductor, any excess charge will distribute itself evenly over the surface of the conductor. Because of quantum mechanics, this is possible with small charges (i.e. 1e). But if electrons were ...
1
vote
0answers
66 views

Electric potential on a uniformly charged tube

A hollow cylinder, with no top or bottom, of radius $R$ and length $L$ is uniformly charged with density $\sigma>0$. I have to find the point on space where a point charge $q>0$ has to be drawn ...
0
votes
1answer
33 views

Charge or Charges on the oil droplets?

Due to my poor understanding of various paper and other material provided by google on Millikan's oil drop experiment I ask the following question here. As the drops were charged by either friction ...
1
vote
2answers
183 views

Oil drop experiment and quantization of charge

How to systematically show that the resulting charges in oil drop experiment are integers multiplied by $e$ in other word how to extract $e$ from the data?
0
votes
2answers
95 views

Electric charge is lorentz invariant

I know that electric charge is lorentz invariant quantity and I can easily think of experiment to check that. Is a though experiment that can prove that also?
2
votes
1answer
43 views

Is charge 'localization' implicit in the idea of current?

If it was possible for charge to assume arbitrary densities, like we often see electrostatic exercises, and one could spread charge density uniformly over a ring, then how one would, theoretically, ...
1
vote
2answers
157 views

How is electric flux related to permittivity?

How is Gauss' law related to permittivity? I know that it equals $1/\epsilon_0$ times the magnitude of the charge enclosed. But, I'm unable to understand what it actually means. Can someone ...
0
votes
1answer
106 views

Why will an accelerated electron emit a photon? [duplicate]

Why will an accelerated electron (or a charge) emit a photon? For example normal matter even if it accelerate or not will emit a photon.
0
votes
1answer
227 views

Electric potential difference from electric field of isolated spherical conductor

I'm wondering if my train of thought is correct. Say you have Point $A$ which is $A$ distance away from the center of an isolated spherical conductor, and Point $B$ which is $B$ distance away from the ...
2
votes
2answers
54 views

Determination of a unique electric and magnetic field produced by a point charge

Let's suppose I have a point charge moving arbitrarily in space. As far I know, Maxwell's equations don't determine a unique electric and magnetic field, they only determine a family of electric and ...
0
votes
1answer
99 views

How is bound charge and free charge possible?

I am studying Introduction to electrodynamics by Griffiths and I came along a concept I cannot seem to understand properly. The concept of free charge AND bound charge. I do not understand how we can ...
8
votes
2answers
200 views

What is the condition for accelerating charge to radiate?

I was always taught that any accelerating charge produces radiation, but I don't think this condition is sufficient condition. For instance, any free charge on Earth is accelerated due to Earth ...
0
votes
0answers
78 views

force on two particles moving with same velocity

When two charged particles having same charge $q$ are at rest, only electric force acts upon it: a repulsive force of magnitude $\frac{kq^2}{r^2}.$ Now let them move with a constant velocity ...
0
votes
1answer
232 views

Frame of reference for moving charge in relation to a magnetic field?

We know that a moving charge produces a magnetic field. But which frame of reference it must move to produce magnetic field? And also if a charged particle moves in a magnetic field, magnetic force ...
-5
votes
1answer
244 views

Are dc and ac currents produce electric field? [closed]

I have four different situation and i want to learn what kind of field (electric or magnetic) each produces and which produces electomagnetic waves? 1)dc current flow in a conductor 2)ac current ...
0
votes
2answers
342 views

How do I express the interaction energy between two charged spheres?

Consider two identical insulating spheres each with radius $R$ and uniform charge $Q$ through their volume. They are separated from their centers by a distance of $d>2R$. Here is my general ...
0
votes
0answers
76 views

What is the electrical field of a capacitor plate as a charge approaches

The electrical field for a charge density $\varrho(r)$ is $${\bf E}({\bf r})=\frac{1}{4\pi\varepsilon_0}\int \varrho({\bf r}')\frac{{\bf r}-{\bf r}'}{\hspace{.1cm }|{\bf r}-{\bf r}'|^3} \mathrm ...
11
votes
1answer
186 views

Do image charges radiate?

Suppose I have a charge moving back and forth above an infinite, grounded, conducting plane. Can I calculate the total radiated power by using image charges? That is, are the scalar and vector ...
1
vote
1answer
92 views

Dielectric modification of electrostatic equations?

I have learnt that in cases of electrostatic fields inside a dielectric of any source charge, the field is reduced by a factor of K( if K, the dielectric "constant", is taken everywhere to be same). ...
-1
votes
2answers
149 views

Do objects have energy because of their charge?

My gut feeling tells me things should have energy because of their charge, like they have energy because of their mass. Is this possible? Has it been shown? If not then what is missing to make such ...
7
votes
0answers
119 views

How can I find the position of an image charge when the boundary is parabolic or hyperbolic?

If the position of some charge Q is known, the boundary condition is u=0 on some parabolic surface, and we know the image charge has its electric volume of Q', then how can I determine the position of ...
3
votes
1answer
482 views

Electric Field due to a charged sphere

Suppose we have a spherical surface with a surface charge density varying as $cos(\theta)$. Apparently one can find the electric field both outside and inside such a spherical surface by superposing ...
6
votes
1answer
648 views

Noether theorem and classical proof of electric charge conservation

How to prove conservation of electric charge using Noether's theorem according to classical (non-quantum) mechanics? I know the proof based on using Klein–Gordon field, but that derivation use ...
0
votes
1answer
252 views

Will I recieve a shock if I charged a capacitor then i touch the 2 poles in same time?

What happens if I charged a capacitor then i touch the 2 poles in same time?
0
votes
1answer
70 views

Can we transfer the charge on a plate of a capacitor elsewhere?

I know it is hard , but can we transfer the charge on a capacitor plate elsewhere?
7
votes
2answers
572 views

why dosen't a charged particle radiate energy in circular motion in a uniform magnetic field?

I have studied in my Physics course that one of the drawbacks of Rutherford's atomic model was that when an electron will revolve around the nucleus, it is undergoing acceleration and so it should ...
3
votes
4answers
864 views

Gravity stronger than electromagnetic force in a black hole?

Well, the question has somewhat been answered before, but there's one part missing, which - I'd think - is in conflict with the physical laws. The earlier reply says that the gravitational pull even ...
3
votes
1answer
172 views

Why are electric charges allowed to be so light but magnetic monopoles have to be so heavy?

My question is in two parts. What is the origin of the electric field from an electric charge and why electron can have so small mass? While on the other hand for a magnetic monopole to create a ...
5
votes
3answers
323 views

Negative Mass and gravitation

Since Newtonian gravity is analogous to electrostatics shouldn't there be something called negative mass? Also, a moving charge generates electric field, but why doesn't a moving mass generate some ...
6
votes
3answers
404 views

Charging a black hole?

What would happen if we have a black hole and we start shooting at it a single electron at a time, and go on doing it forever? Would the electrons start to bounce off eventually?
8
votes
3answers
1k views

What is the symmetry which is responsible for preservation/conservation of electrical charges?

Another Noether's theorem question, this time about electrical charge. According to Noether's theorem, all conservation laws originate from invariance of a system to shifts in a certain space. For ...