Electrostatics is concerned with the electrical fields and scalar potentials of stationary electrical charges and charge distributions. Use this for questions about electromagnetic situations in which currents and magnetic fields are absent, otherwise use [tag:electromagnetism] and/or [tag:magnetic-...

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Please Can Anyone help Me to drive the equation for Electric Field Around a test Charge Around A uniform Ring. [closed]

Please can i get a mathematical relation for electric Field around a test Charge Lying in the region of influence around a uniformly Distributed Charged Ring .
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1answer
170 views

How to calculate the electric energy caused by eletrostatic field stored in a region, given $V$? [closed]

I have problem in apply the rules to find the energy stored in free space here is the problem Find the energy stored in free space for the region $$0.002<r<0.003m,\quad 0<\phi<\frac{\...
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Self Energy (Classical Electrostatics)

In classical electrostatics, the total energy is given by $W_T=\frac{\varepsilon_0}{2}\int_{\mathcal{U}}{\left|E(\vec{r}')\right|^2 \mathrm d\tau'}$ , while the interaction term is $$W_I = {\...
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the mathematical relation between dipole moment and frecquency

Is there any direct mathematical relationship between frequency and dipole moment and if so does it fit if there more than one electric field affect it?
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Time in Coulomb's law [duplicate]

If you have an electric charge somewhere and you make a new electric charge right now when do these electric charges start to interact with each other? is it immediately or it take some time ? how ...
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1answer
9k views

Charge inside conductor

I know that the $E$ field inside a conductor is zero. What happens if I put a source of charge inside the conductor? Say the conductor was spherical centered on the origin and there exists a charge ...
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2answers
17 views

Electric potential energy of a charge

Potential energy is the work done by the particle against a conservative force. Isn't it? when a charge is fixed on a free space and then when we bring another charge from infinity to a distance r ...
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44 views

Charged conducting wire ring and Greens function

ρ(r) = q 2πa2 δ(r − a)δ(cos θ). If this is my charge distribution on a conducting wire ring. radius=a. I am attempting to show my electrostatic potential as an integral along the z-axis I started by ...
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22 views

Multipole expansion of the electric field generated by an infinite charged plane

Take an infinite plate with uniform charge density, the classical problem that is usually solved with Gauss' theorem, to get that the electric field outside the plane, at a point $\boldsymbol r$ is: $$...
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1answer
258 views

Basic electrostatics - Poisson's Equation

I would like to solve Poisson's Equation for a space charge region (fixed and free charges) that is located within a device of semiconductor material. Unfortunately I do not have any boundary ...
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1answer
30 views

Total potential energy in electric field?

if there are 2 charges generally potential energy of the system should be the sum of individual potential energy. but why the potential energy is half of the sum of every individual charge's potential ...
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1answer
39 views

Does a conductor in an external electric field have a positive charge density and electric field inside?

I'm thoroughly confused by conductors. Let's say you have a round(ish), perfect conductor. Solid and uncharged. Some distance from it, we place a point charge $q$, giving rise to a field $\vec{E}$. ...
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55 views

How and why do electric fields occur when we put a voltage difference between two point?

When we put a voltage differences between two points on a certain sample, I would like to know how and why the electric field occurs. In addition, I would like to know in what shape does the electric ...
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42 views

Method of image charges — Why is a *grounded* plate needed?

In the classic image charge problem of a charge $q$ above an infinite grounded plane, it is well known that the field lines essentially behave as though there were a negative charge behind it, and the ...
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47 views

When deriving potential between plates of parallel plate capacitor, why isn't the charge distributed on the top *and* bottom of both plates?

Let's say we have a canonical parallel plate capacitor with area $A$ and separation $d$ where $A>> d^2$. A charge of $+Q$ is placed on the top plate and $-Q$ is placed on the bottom plate. We ...
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2answers
41 views

Electric field Intensity , parallel plates

My book says that the electric field due to infinite long plates doesn't depend on 'r', so does it mean that no work is done in moving a point charge towards or away from it? Also considering the ...
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coaxial capacitor potential calculation

How is capacitance of a cylindrical capacitor calculated? In his question his Equation 1 tells us how to calculate the potential of a cylindrical object and there are two locations where I cannot ...
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1answer
28 views

Local charge density manipulation of ionized air

Assume we have ionized the air in an isolated container. Would is be possible to concentrate the ions within a specific region of the container with electric fields, i.e. to manipulate local charge ...
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89 views

Why charge is not a measure of inertia?

We know that mass is the measure of inertia of rest. Then why charge is not a measure of inertia? What causes the difference between charge and mass?
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1answer
19 views

About Electric potential

when we bring a unit positive charge from infinity to a point in the electric field EF does work on the charge and external work is also done on the charge in same amount but in opposite sign. then ...
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21 views

Null point (vector) between n point charges

I have derived the result for 2 positive charges, and for one positive one negative can be obtained by using the minus sign correctly. But I was unable to extend it or solve for n charges. Is my ...
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5answers
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The discontinuity of Electric Field

''electric field always undergoes a discontinuity when you cross a surface charge $\sigma$'' GRIFFITHS In the derivation; Suppose we draw a wafer-thin Gaussian Pillbox, extended just barely over the ...
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1answer
51 views

Variation of electric field with volume of dielectric in space

Suppose there are 2 spheres which have charges $+q$ and $-q$ and separated by a distance d. Let the field be $\vec{E_0}$. Now I bring a dielectric rod which is eqal in length to the separation ...
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What is the net charge of the Earth?

This question arose in a seminar today about the solar wind... This is my vagueish understanding of the problem - please correct if you see errors! The 'classical' picture of atmospheric electricity ...
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3answers
71 views

Electric Field Inside a Conductor at Different Charge Densities [closed]

We say that the magnitude of the electric field inside a conductor is zero, whether a hollow or solid. However, at certain charge densities, the magnitude of the electric field inside the conductor ...
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28 views

How does air density affect corona discharge?

I'm wondering how local air pressure and density affect the amount of ionizations occurring in a corona discharge. Also, does the threshold voltage required for a corona discharge vary with air ...
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39 views

Force on a charge due to charged sheet

I want to find the force on a positive charge placed at a distance $d$ from a positively charged infinite plate. Of course, it can simply be done by finding the electric field due the plate using ...
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1answer
47 views

Dipole in electric field

An electric dipole is placed in a uniform electric field at some angle, say 90 degrees. The dipole consists of 2 charges, one negative and one positive. The charge which is positive will have a torque ...
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1answer
51 views

Are objects generally neutral or charged?

Basically the questions relates to what is taught about electroneutrality and has 2 parts: Is the overall charge in the universe zero? Are objects the world generally neutral or slightly charged, ...
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Are electric field lines always conserved?

Suppose we have a positive +q charge and a -6q charge at some separation. Then will every field line originate from the +q and end up to -6q or will there be some extra lines coming to -6q from ...
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18 views

When is the condition $V(x_i\rightarrow \infty)=0$ needed when solving the Laplace equation?

Im currently working on the solution of some Laplace Problems with Griffiths (Page 180). Often the condition $V(x_i\rightarrow \infty)=0$ appears when discussing problems of conducting plates, for ...
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1answer
53 views

Conservation of Energy of two charged blocks connected by light spring

Two identical blocks resting on a frictionless, horizontal surface are connected by a light spring having a spring constant $k = 100 N/m$ and an unstretched length $L_i=0.400 m$. A charge $Q$ is ...
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3answers
77 views

Voltage drop across capacitors in series, why?

Basically when you connect more than 1 capacitor in series then the charge on each capacitor is same but there is a voltage drop across each capacitor. I have no intuition as to why the voltage drop ...
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3answers
712 views

Why is there electric field OUTSIDE a battery?

Correct me if I'm wrong, but a battery's electric field is like an electric field of a capacitor consisting of two parallel plates. But we know that the electric field outside the two plates is zero. ...
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Is frictional heat just electromagnetic interactions creating infrared radiation?

Example: Rub your index finger on a sheet of paper and you will feel that it will get noticeably hotter Is the reason you feel this increase in heat (technically an increase in kinetic energy of the ...
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2answers
10k views

If we change the radius of spherical surface does electric field or flux change?

Suppose a point charge is located at the center of a spherical surface. The electric field at the surface of the sphere and the total flux through the sphere are determined. 1).What happens to ...
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1answer
77 views

“Why electrons don't fall into nucleus”simple explanation needed [duplicate]

Am studying in 8th grade and I studied electrostatic force which says opposite charge attracts and same charges repel But in an atom electron is just situated above the proton and it doesn't attracts....
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2answers
43 views

Electrostatics Of Conductors

My textbook says that no excess charge can reside inside the conductor because electric field inside a conductor is 0. But say i introduce a positive charge inside a conductor, it generates its own ...
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3answers
203 views

Directly calculate electric potential due to a spherical volume charge

Q: Say we have a uniformly charged sphere with radius $R$, total charge $Q$. Now we need to find out the electric potential inside the sphere, at a distance r from the centre. I understand that we ...
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3answers
3k views

Do electric and magnetic lines of force physically exist?

As per my imagination any thing can't impose force on the other by not giving even a touch(i,e action at a distance). So I thought there must be some physical existence of lines of force. Although ...
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1answer
61 views

Electric potential of dipole

We have proton and electron and distance between them is $d$. If we choose $z$ axis along this dipole, net electric potential created by dipole on the point A is equal to summation of the electric ...
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2answers
31 views

How will the charges redistribute when a conductor is in contact with a uniformly charged material?

This is a conceptual question but it is just a bit tricky, Under the influence of E-field any charges that accumulates within the conductor redistributes to the surface. So when an uncharged ...
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1answer
13 views

PD and Current path in CROs

I have few questions regarding CROs . 1 I want to know that how cathode grid and pre accelerating and accelerating grid are higly charge .? 2 They are connected to same battery or different batteries ...
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34 views

Electrostatic potential due to angular dependent spherical charge distribution

Problem: Given the charge density $\rho = \rho_0 \frac{r}{a}\sin{\theta} \sin{\phi}$ for $r<a$, and $0$ for $r>a$, calculate the electrostatic potential. Issue: I have previously done a ...
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0answers
32 views

Components of electric field deriving from potential equetion [closed]

My question is abut finding components of electric field from potential function. $V=\frac{1}{4\pi\epsilon_0}\frac{\vec{p}\cdot\vec{r}}{r^3}$ (1) I can write it as $V=\frac{1}{4\pi\epsilon_0}\frac{pz}...
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1answer
3k views

Force between two point dipoles

What would the force between two parallel point dipoles be? I was thinking of doing it the way force between two point charges is found out, by finding the field and then the force but I am not able ...
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0answers
29 views

Image charges and image-image interactions

Say you have 2 point charges (labelled R1 and R2) above a perfectly conducting flat surface. To fully treat this system using the method of image charges (labelled I1 and I2) should interactions ...
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0answers
60 views

Charge distribution around ring such that electric field is zero along diameter [closed]

"Design the charge distribution along a ring to make the electric field along its horizonatal diameter AB zero. The total charge is Q" Considering the electric field needs to be zero along the whole ...
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2answers
102 views

Electric field between 2 parallel plates

The question state that 2 large parallel plates are a distance $d$ apart and the field at $d/2$ is $E$ if the distance between the plates are reduced to $\frac{d}{2}$ what is the field strength ...
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4answers
257 views

Is it possible that the charged sphere can lose mass by adding electron?

While studying Electrostatics, I was wondering about whether a charged sphere gains or loses mass while just adding electrons? If it is possible then the negatively charged sphere will have more mass ...