Questions tagged [charge]
A fundamental property of matter which causes it to experience electromagnetic forces.
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When a charge starts moving, does it's electric field change into magnetic field? [duplicate]
If the electric field does change into magnetic field, how does it happen?
And if it doesn't happen, then what happens to the electric field?
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2answers
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A “lightning” came out of the outlet and shocked me. How?
I was sitting in my bed using my computer. It was almost out of battery, so I got up and grabbed the charger to connect to the outlet. Then a strange thing happened: when my hand got near the outlet, ...
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1answer
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Why are there no radiative corrections to the electron charge for (an on-shell interaction)?
My question stems from the preliminary discussion of the electron vertex function found in section 6.2 of Peskin and Schroeder's Introduction to Quantum Field Theory.
Specifically, they calculate the ...
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Discharging a photoconductor from the substrate side [on hold]
Is it possible to discharge for example an OPC drum without exposing the surface? Since they are usually build on aluminum tubes (and belt type OPCs on metallized PET or other polymer) could one drop ...
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1answer
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Surface charge density from volume charge density [on hold]
I'm working on a problem taken from Zangwill's Modern Electrodynamics, where I'm asked to derive the well known result of the electric field $\mathbf{\vec{E}(\vec{r})}$ both inside and outside a ...
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1answer
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Particle collision and mass relation
Is mass important in calculations when two particles are collide? or is only the charge that matters? is collision in microscopic world the same with macroscopic world?
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Is (DC/battery) voltage a result of charge? or energy? or both?
Backstory: I’m a software engineer just getting into electronics and it seems that everything I’ve ever been told about electricity my whole life is a candy-coated lie. I can’t find consistent logical ...
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4answers
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How does resistance *really* work? (DC, battery, LED, atoms, electrons)
Backstory: I’m a software engineer just getting into electronics and it seems that everything I’ve ever been told about electricity my whole life is a candy-coated lie. I can’t find consistent logical ...
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1answer
58 views
If strings of matter are of the same substance how can matter carry differing charges?
Considering that a string is a loop of energy composed of the same underlying material how is it possible for it to be either positively or negatively charged? For that matter, how is it possible for ...
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3answers
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Do real electrons solve the Thomson Problem?
The question of how $N$ electrons (seen as point charges) on a conducting sphere will arrange themselves in the electrostatic final state was first posed by J.J. Thomson in 1904--hence, aka the ...
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1answer
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Energy of photon and charge [on hold]
What is the significance if any of the common energy value of the electron volt $(1.602 \times 10^{-19}$ joules), and the energy of a photon of wavelength $ \sim 1230$ nm (from the formula $E=h \nu$)?
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Charge of multiverse
The charge of the universe is said to be zero. The most general argument I hear about this is that: since there was no net charge before the universe there must not be any after. Hence the universe is ...
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2answers
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Proof that electrostatic self-force is zero
Suppose there is a charge distribution in region V and zero charge density outside V such that electric field goes to zero infinitely far away. How to prove that this charged body does not exert an ...
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Experiment interpretation. Dielectric polarization/triboelectricity/other?
My aim was to create a relatively strong electrostatic field to experiment with biological systems. So, I built a kind of "sandwich" made of a plate of aluminium surrounded by two 4mm plates of ...
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Charge concept before discovery of electron [migrated]
How the concept of positive and negative chrge originate before discovery of electron.my question is about.
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2answers
60 views
Charge Distribution on a perfectly conducting hollow shell
As shown in the figure, I have a hollow shell which contains a charge at its centre and another charge is placed outside the shell (some distance apart).
I know that the situation this figure depicts ...
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1answer
53 views
From where to start such a question? [duplicate]
13 equal charges, q , are placed at the corners of a 13 sided regular polygon. What is the force on a test charge Q at the centre?
I couldn't figure out from where to start solving it. It would be ...
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2answers
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Am I positively charged or negatively charged?
We often hear that the human body has a weak electrical charge. Is it a positive charge or negative charge? Or maybe different parts of me have different electrical charges? Or maybe there's a ...
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1answer
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Alternative particle types?
If we consider mass and charge to be excitations of independent quantum fields, do they necessarily travel together? Can we have objects with only an excitation on the mass field, and objects with ...
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1answer
59 views
What drives the charge separation in atoms?
In atoms charges are neatly separated. Instead of pairing which seems natural they all stick together with their peers.
What drives this peer behaviour? Why is it stable?
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6answers
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Why doesn’t current decrease when it passes through a resistor?
As far as I know current is the amount of charge passing per unit time.
$$I=q/t$$
When current passes through a resistor, the resistor resists the flow of current so the amount of charge going to ...
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4answers
147 views
How does Superposition principle follow from Maxwell's equation's linearity?
It is said that whole of electromagnetism can be completely described by the Maxwell's equations.
The thing that intrigues me is that how does superposition principle follow?
First, I take an ...
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0answers
32 views
Why are(n’t) rechargeable batteries damaged by partial charging?
Originally asked in ElectricalEngineering.SE, but I was told Physics.SE might be a better place to ask.
Over the years, I've come across websites and people with different opinions on the "correct" ...
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1answer
21 views
Ratio of charges between capacitors in parallel and in series [closed]
Context: this is a multiple choice question, but no explanation is given
Question: three capacitors of equal capacitance are connected in the following circuit. Determine the ratio of charge in ...
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2answers
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Leptons during Electroweak Epoch
Prior to the electroweak force splitting, did charged leptons still carry a charge of $e$? I was under the impression that, since electromagnetism didn't exist in its current state prior to ...
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1answer
26 views
Does a field gain energy or does the mass/charge?
My textbook reads that when a mass/ charge is moved into the influence of a gravitational/ electric field the field gains/ loses energy rather than the mass/ charge. How can this be explained?
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1answer
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Charge density of sea water
If sea water contains salt ions and some H+ and OH- ions, what are the charge density of a certain volume of sea water? And is there a way to calculate?
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1answer
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Resultant effect of orthogonal motion of electric charges
*If two charges are moving uniformly with parallel velocity vectors that are not perpendicular to the line joining the charges, then the net mutual forces are equal and opposite but do not lie along ...
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1answer
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A fundamental question about charge and speed of a particle [duplicate]
Hi everybody and happy 2019. In my teaching sessions sometimes someone asks questions i cannot truly answer (although i have many arguments on it) and here's one that really puzzles me:
A massless (...
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2answers
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Inconsistency in the definition of electrostatic work
Sorry if there this is a duplicate but I can't find anything that deals with this.
I have a point charge $q$ sitting at the origin. It takes no work for me to put it there.
Then, I bring $-q$ out ...
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0answers
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Why is there an accumulation of charges at the junction of 2 rods of different metals joined together?
Let two similar rods of different metals ( say copper and iron ) are joined together and some current is let to flow . Is there a charge accumulation at the junction?
1. If so what is the cause of it ...
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1answer
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If monopoles are excised points in a $U(1)$ bundle, how are they affected by other charges?
We currently understand electromagnetism as a U(1) gauge theory. If you take a point out the space manifold (base space) you can create magnetic monopoles with integral charges by making non-trivial ...
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3answers
283 views
Superposition Principle for Electric Fields
If there is a collection of charges $q_1,q_2,q_3....q_n$, and we want to calculate the total Electric Field due to all these charges at a point $P$ ,then the we sum them all up by the principle of ...
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3answers
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How to find electric field at a point on an arbitrary surface charge $(\sigma)$ due to it?
Electric field at any point due to any volume charge $(\rho)$
Electric field at a point outside a volume charge is given by Coulomb's law:
$$\vec{E}=k \iiint_V \dfrac{\rho}{r^2} (\hat{r})dV \tag1$$
...
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1answer
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Can 2 charged black holes repel each other?
Say there are 2 stellar black holes (equal mass and like charged), can they repel each other? I believe when people say things like charged black hole it is not the same as magnetar where it generates ...
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2answers
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Question on capacitance
I am recently trying to learn electrics on my own but am a bit confused with regard to capacitance. By Gauss law, I understand that the electric field from a single parallel plate results in:
$$ E = \...
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1answer
130 views
Coulomb's Law modified in general relativity?
It seems difficult to track down a clear explanation of this statement:
So although the Coulomb law was discovered in a supporting frame, general relativity tells us that the field of such a charge ...
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Capacitance of spherical capacitor when inner sphere is earthed
Consider the following derivation:
(Source: http://www.ncert.nic.in/html/learning_basket/electricity/electricity/electrostatics/inner_sphere.htm)
If a charge of $+Q$ coulombs is given to the outer ...
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1answer
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Electric field at a point infinitely close to an arbitrary surface charge [closed]
My question is of two parts:
(i) I know electric field due to an infinite plane sheet of charge at a point (finite distance $d$ away) is $2 \pi\ k\ \sigma$. From this, by reducing the linear ...
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1answer
36 views
Does electric field carry charges?
A charged particle say an electron carries a negative charge and it will experience a force when there is an electric field, like charges repel and unlike charges attract so does this means an ...
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1answer
21 views
Why does electric field undergo a discontinuity when we cross $any$ surface charge $σ$?
According to Griffith's book on electrodynamics, electric field always undergoes a discontinuity when crossing a surface charge $σ$. I do understand that in certain cases like the surface of a ...
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1answer
62 views
How to think about color charged objects
When imagining color charged objects, I know we can treat color and anti-color much like electromagnetism. What I'm having trouble with is imagining the interaction of similarly coloured objects. Now ...
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EM Induction in non-uniformly conducting ohmic toroid, thought experiment
Assume that there's a conducting toroid with radius of revolution $R$ and an own radius of $D$ so that the cross section of the toroid is given by $\pi D^2$
Assume that there's a circular region of ...
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2answers
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Would a charge imbalance act like dark energy?
I realize that there are theoretical reasons to reject the idea that the charges on electrons and protons may not be exactly equal and opposite; and I am not suggesting that they're not.
Edited 12/20/...
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Electric field inside a cylinder containing a grounded wire?
Say we have a hollow cylinder at 100V.
I understand that if this cylinder were empty, you would have no electric field inside because if you drew a Gaussian surface, it would contain no charge.
...
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1answer
31 views
Electrostatics question inquiry [closed]
The answer is C given that the left ball is positively charged. But since the sphere is heavily positively charged, shouldn’t the sphere repel the left positively charged ball rather than the left ...
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1answer
44 views
Is there any difference between Photon produced from proton and electron?
I know that accelerated charged particle produces Photon but is there any difference between photon produced from a positive and negative charge?
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Force exerted on an uncharged particle in a uniform magnetic field?
I'm struggling to understand how to calculate the force exerted on an uncharged particle in a magnetic field. Consider the following setup: a ball of ferromagnetic iron weighing 1kg is placed in a ...
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2answers
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(Two fixed charges add in a third), why does it matter which side I put the third charge if I change signs accordingly?
So the question is "Two charges, 1.0 micro-Coulombs and -3.0 micro-Coulombs, are 10 cm apart. Where can a third charge be located so that no net electrostatic force acts on it?". Now the instructor ...
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Hanging two charged sphere by a light string
NB: This is not a homework question. I am not searching for any solution of a math problem.
I found something incorrect to do always in the nature of two charged pith balls hanging from a light ...
