Electrostatics is concerned with the field and potential of stationary electrical charges and electric charge distributions. Problems are this type are almost exclusively concerned with mathematics of geometries using the inverse-square law.
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Why doesn't an electrometer's capacitance influence the measurement of voltage?
I've read on the subject in several books, and none of them mentioned whether we can neglect electrometer's influence on the measurement of the voltage or not. Maybe my question sounds a bit stupid, ...
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0answers
50 views
Method of images tutorial?
I'm having an exam in Electrodynamics soon. I think I have most of it under control, but the method of images I'm not quite sure about.
There is not much in my book about, so I was thinking some of ...
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4answers
56 views
Capacitors' working in a circuit
Does charge in a capacitor containing circuit stop flowing when the potential of the capacitor becomes equal to the potential of the battery??
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2answers
28 views
In electrostatics total flux linked from the closed surface enclosing the charge is equal to $Q/\varepsilon_0$. This is according to Gauss Law
In electrostatics total flux linked from the closed surface enclosing the charge is equal to $Q/\varepsilon_0$. This is according to Gauss Law.
Is this the experimental value or defined value. If ...
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0answers
30 views
Esd safety when working with printed ciruct boards. What is the risk of damaging circuit boards when working in non esd safe chair, vs a esd chair?
esd safety when working with printed ciruct boards. What is the risk of damaging circuit boards when working in non esd safe chair, vs a esd chair? When everything else is grounded. e.g I am wearing a ...
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0answers
21 views
Dipole moment dilemmas
Dipole moment for a couple of charges, say q and -q, separated by a distance 'd' is given by 'qd'
But what is for dissimilar magnitudes,say (q and 2q) or (q and -2q)?
And are dipole moment defined ...
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1answer
23 views
charge placed on a capacitor [closed]
a parallel plate capacitor has plate area of 0.0025 m^2 and distance between the plate of 2.0 mm. Determine the maximum charge that can be place on the capacitor if air is the dielectric substance
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2answers
28 views
Question regarding inverse relation of resistance with area of cross section
It is said that resistance is inversely proportional to area of cross section. But greater area will have greater electric flux, and greater electric flux will have greater magnetic flux, and greater ...
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0answers
44 views
Capacitors connected [closed]
Two capacitors of capacitances 3 $\mu{F}$ and 6 $\mu{F}$ are charged to a potential of 12V each.
They are now connected to each other, with the positive plate of each joined to negative plate of the ...
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0answers
52 views
Finding equivalent capacitance between points in a cubic arrangement of capacitors [closed]
Each of the edge of a cube is containing a capacitor of capacitance 'C'. Find the equivalent capacitance between:
1 and 7
1 and 4
1 and 8
I am done with the first part to ...
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0answers
70 views
finding minimum electrostatic energy [closed]
There are 2 small metal balls of radius $r_1$ and $r_2$ which are kept at very large distance. What should the ratio of charges on them be for the electrostatic energy to be minimum?
In this problem, ...
2
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1answer
44 views
How are excess charges distributed over non-spherical conductors?
My textbook gives the following explanation on how excess charges are spread over conductors:
The excess charge on an isolated conductor moves entirely to the
conductor's surface. However, ...
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2answers
40 views
What is a good read about Manning condensation? [closed]
I was assign in a course to give half an hour talk about Manning condensation. I read Wikipedia article about it as a starter, but it's only two paragraphs long and only point to the original paper ...
2
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1answer
87 views
Mathematical problem in integral arising in electrodynamics
I want to calculate the total electrostatic energy of the Cavendish Experiment (two concentric spheres of radii $R_{1,2}$ which are connected, outer one gets charged, then removed, then after removing ...
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2answers
54 views
Electric Field Lines between two non parallel plates [closed]
A potential difference is applied between two metal plates that are not parallel.
Which diagram shows the electric field between the plates?
A is the answer BUT WHY explanation needed !
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2answers
28 views
How charge distribution takes place when a battery is connected to a conductor?
When one terminal of a battery say of 1.5 volt connected to a short length wire, few electrons get transferred from battery terminal to the wire raising the potential of the wire also to 1.5 volt. We ...
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2answers
83 views
Field lines question
A friend of mine asked me this question, that is asked in an entrance examination.
It shouldn't be that difficult, but I fail to find a rigorous answer for it.
The figure shows three charges, that ...
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3answers
98 views
Conductors connected with a wire
Let's say I have two spherical conductors with different radii and different amount of positive charge on them. The spheres are far enough from each other. I connect them with a conducting wire. I'm ...
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0answers
74 views
Deflection/diffraction of static electric field
I know the fenomenon of diffraction (one slit) in case of electromagnetic waves.
http://en.wikipedia.org/wiki/Diffraction
What happens if there is only a static electric field?
Let' see a figure:
...
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0answers
15 views
How can I calculate numerically an electrical potential distribution from an electric field distribution? [migrated]
I want to calculate the unknown electrical potential distribution $\phi(x)$ (notice this is a function of $x$) from a known electric field distribution $\boldsymbol{E}(x)$ using the Poisson equation,
...
3
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1answer
60 views
Electric field a distance $z$ above the center of a circular loop. The Hard way [closed]
Problem 2.5: Find the electric field a distance $z$ above the center of a circular loop of radius $r$ which carries a uniform line charge $\lambda$.
This problem is in refereced here (with ...
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1answer
37 views
Behavior of the electric field on boundary surfaces
Consider this picture.
Integrating over this infinitesimal box gives the following equivalencies:
$$\int_{\Delta V} d^3r~{\rm div} \vec{E}(\vec{r}) = \int_{S(\Delta V)} d\vec{f} \cdot ...
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1answer
42 views
Charge in a layered ball
A ball (radius $R$) has three layers. For $0<r<a$ it is a conductor with free charge $+Q$. For $a<r<b$ it is a linear dielectric $\epsilon$ with free charge embedded in it with density ...
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0answers
40 views
Modeling the formation of a stellar system and matter accretion
I am trying to figure out what do I need to know to properly simulate the creation of a solar system from a particle cloud with random distribution of hydrogen atoms.
Being more of a programming ...
2
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1answer
77 views
Boundary conditions for Laplace's equation
Given a grounded conducting sphere, $V=0$ and $radius = R$, centered at the origin with a pure electric dipole (dipole moment $\vec p$) situated at the origin and pointing along the positive $z$ axis, ...
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1answer
50 views
Potential due to charged particle $Q$ placed at a distance $L$ from uncharged conducting sphere [closed]
What is the potential due to charged particle $Q$ placed at a distance $L$ from uncharged conducting sphere?
Is it $\frac{kQ}{L }$ or $\frac{kQ}{L} + \frac{kq}{R}$, where $q$ is the charge induced on ...
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1answer
28 views
How can the accurate value of electric field intensity be calculated?
When we calculate electric field intensity for a point charge at any point inside electric field the field intensity is $E = F/q$ where $F$ is the force acting on charge $q$. In this case, the charge ...
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0answers
33 views
Is Gauss' law useful to determine the electric field strength of a charge distribution? [closed]
Under what conditions is useful Gauss' law to determine the electric field strength of a charge distribution? Can someone help me with this question?
4
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1answer
89 views
How much negative charge do I accumulate by touching the earth?
The Earth carries a negative electric charge of roughly 500 thousand Coulombs (according to different sources I've seen). If I touch the Earth I should therefore pick up some of this electric charge ...
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2answers
125 views
Hexadecapole potential using point particles?
We can get monopole $1/r$, dipole $1/r^2$, quadrupole $1/r^3$ and octupole $1/r^4$ potential falloff by placing opposite point charges at the corners of a point, line, square and cube, respectively. ...
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0answers
37 views
How the value of permitivity of free space is determined?
when electric charges are placed on the medium then force of interaction between them decreases. We say this factor permitivity of the medium. The force of interaction between the charges is max if ...
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1answer
74 views
Electric dipole moment, which charge is the $q$ for?
Electric dipole moment says $p = qd$. Which charge does the $q$ equal to?
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0answers
21 views
Electric Field and Electric Potential [closed]
How can electric field and electric potential function for charged conducting and uniformly charged non-conducting spheres?
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2answers
63 views
Kinetic energy of two charged balls at infinite distance between them
If I have two balls with masses and charges $m_1, q_1^{+}$, $m_2, q_2^{+}$, initially held at distance $d$, and then released, how can I know the kinetic energies of each of the balls at infinite ...
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1answer
64 views
What is the electric field in a parallel plate capacitor?
When we find the electric field between the plates of a parallel plate capacitor we assume that the electric field from both plates is $${\bf E}=\frac{\sigma}{2\epsilon_0}\hat{n.}$$ The factor of two ...
2
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2answers
119 views
Force Between Two Conducting Spheres
Aakash PHYSICS JEE (Main & Advanced) Study Package - 5 & 6 (Class XII)
Chapter - Electric Charges and Field
Assignment (page 12)
SECTION - A; Q.no - 1
...
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1answer
31 views
Potential on a Charged Sheet
I know the field difference across a charged sheet-but what's the potential on a charged sheet? Is it just asymptotic?
If we had a thin cylindrical sheet would it be the same? Zero field inside the ...
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1answer
53 views
Why is the void devoid of an electric field?
For a region devoid of charge, maxwell's equation yields $\nabla \cdot \mathbf{E} = 0$ which still allows a constant field. So why is in electrostatics for the vacuum always $\mathbf{E} = 0$ assumed?
...
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1answer
27 views
Speakers and Static from Hands
Why is it that when you touch the a bare male end of a speaker feed that the speaker makes hissing noises? Is it just (eddy?) currents running through you?
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2answers
48 views
Do black holes have charges?
Do black holes have charges? If so, how would they be measured? Also, does electricity behave the same way? Black holes affect photons, which are carriers of EM radiation, so do black holes have any ...
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1answer
86 views
What are the limits of applicability of Coulomb's Law?
Coulomb's law is formally parallel to Newton's Law of Universal Gravitation, which is known to give way to General Relativity for very large masses. Does Coulomb's Law have any similar limits of ...
3
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3answers
151 views
Gauss' law and an external charge
Gauss' law states that the net outward normal electric flux through a closed surface is equal to $q_{total, inside}/\epsilon_0$. However, I'm a bit confused of why the presence of an external charge ...
5
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2answers
169 views
Is there a momentum for charge?
Since mass and charge behave similarly, so, just like center of mass, I define a point center of charge, that is defined by
$$\vec r_{qm} = \frac {\sum{q_i \vec r_i}} {\sum{q_i}}$$
where $\vec r_i$ ...
5
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3answers
125 views
Horizontal $E$-field for a charged conducting disk
For part of a simulation I am writing, I need to know the electric field emitted from a charged conducting disk. If the disk was laid out in the $x$-$y$ plane, I am interested in the field in that ...
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1answer
55 views
What types of materials can be electrically charged by rubbing?
What types of materials can be electrically charged by rubbing? Is there a certain type of materials in which static electricity can be produced by rubbing together two different materials?
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2answers
151 views
Definition of electric charge and proper explanation
Is there a definition of electric charge and proper explanation of it?
It is said "Electric charge is the physical property of matter that causes it to experience a force when close to other ...
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2answers
84 views
The electric potential and the electric field
I'm preparing for my school exam in physics and I found that I don't understand the derivation of $E = -\nablaφ$. Here is a derivation from my book:
1) Imagine that 1 and 2 are infinitely close ...
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0answers
23 views
Electrostats and Photoelectric effect [closed]
Here I think ,
one beam will knock out just one electron. So I am not able to even understand what the question says , please someone give a hint as to what the question asks
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1answer
43 views
Electric Field in Dieletric
I have a simple doubt. The textbook I'm working with says that if $E_0$ is the electric field in some region without diletric, then if we introduce a dieletric of constant $k$ the new field will ...
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2answers
73 views
Confused about the electric field at the surface of a conductor
We know that the electric field at the surface of a conductor only have a normal component equal to $\rho/\varepsilon$ (finite number).
But let’s consider the point $\text{P}$ (at the surface of a ...
