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 ...

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Electrostatics Problem - A non-conducting cylinder

A nonconducting cylinder of radius 1.20 meters and length 2.00 meters carries a charge of 50 micro-coulombs uniformly distributed throughout the cylinder.Find the electric field on the cylinder axis ...
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1answer
28 views

Would a non-conducting body ever acquire a uniform static charge throughout it's volume?

I'm studying electromagnetism and optics in first year and solving a lot of problems involving conveniently symmetrical conducting and non-conducting bodies having various uniformly distributed ...
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2answers
57 views

Are spherical coordinates distances or angles?

I've become confused about spherical coordinates when dealing with electric fields. The way I always understood spherical coordinates is something like the below picture. To define a vector, you give ...
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0answers
18 views

What is the speed of the panel when the spacing between the plates increases [on hold]

Flat-panel capacitor WITH the surface area of $200 cm^2$ is connected to the voltage $1000 V$. One of the plates we start to move away from a constant force $5\times10^{-4}$ Newtons. the spacing ...
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1answer
14 views

Change in Potential energy moving toward line of charge

I'm analyzing the energy involved with charges moving in an electric field and I'm getting caught up here and I must be missing something. So given that an infinitely long line of charge produces a ...
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1answer
21 views

Total potential energy for two charged particles

I'm trying to formulate a Lagrangian equation for a system of two charged particles. They have respective masses $m_1$ and $m_2$, and respective position vectors $\vec{x_1}(t)$ and $\vec{x_2}(t)$. ...
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1answer
25 views

Constant charge density and magnetic field

Suppose we have an arbitrary number of point charges in a vacuum, described by a constant charge density $\rho$. Can they be the sources of a magnetic field $\mathbf{B}$? My intuition is that they ...
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37 views

The approximation of the potential field of a half wave dipole antenna

I'm currently deriving an approximation of the potential field of an dipole antenna in the far-field in two dimensions, and I have some troubles. Since using two methods give two different answers. ...
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1answer
45 views

Gauss's law and charge on surface

Consider a cone (not necessarily right cone), with a charge $q$ at its apex. Fix its base, and let the vertex be movable. Now suppose we intend to find the flux through the base. Since the flux ...
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1answer
19 views

Electric Flux through metal plate by uniformly charged wire

Suppose a long uniformly charged wire is placed parallel to a thin uniform metal plate of length l and width w.Distance is r.Then how to calculate the electric flux through the plate if the charge ...
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45 views

Electric field outside a sphere

The sphere $K\subseteq R^3$ with radius $R$ has a homogeneous charge density $\rho$. Find the electric field E, produced by K outside of, meaning, find the integral ...
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1answer
28 views

Can a proton be trapped by eight other protons?

Q: Eight protons are permanently fixed on the corners of a cube. There's a ninth proton floating at the centre of the cube. Is there an escape for the proton or is it trapped? Justify with a ...
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1answer
41 views

Are $Q1$ and $Q2$ attracted or repelled to the sphere shown in the figure below? [closed]

Can you tell from the image below if Q1 and Q2 are attracted or repelled. Will Q2 only be attracted to the sphere if Q2 is enough bigger than Q1? Will the positive charge inside the shell attract ...
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19 views

Find direction and magnitude of net electrostatic force on a point charge [on hold]

Question: Find the direction and magnitude of the net electrostatic force exerted on the point charge $q_2$. Let $q = +2.4μC$ and $d = 33cm$. What I tried: I used the formula $F = kq_1q_2/d^2$ to ...
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1answer
35 views

Understanding electric field and potential inside an half-connected wire

Let's say we have a 9 V battery and a wire as shown in the image below: Let's assume H is the reference for measuring potential. I know the potential in F is 9 V, and I know the electric field in F ...
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1answer
37 views

Why did the electric potential energy fall in this situation?

Suppose you have two capacitors configured as shown in the image below. One of them has charge $q$ and the other one is uncharged. Then, you close the switch, allowing charges to flow. After ...
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2answers
34 views

Electrostatics question cbse 2015 [closed]

''The outward electric Flux due to charge +Q is independent of the shape and size of the surface which encloses it.'' Give two reasons to justify this statement.
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1answer
26 views

In a spherical distribution the charge density varies as ρ=A/R [closed]

ATTEMPT: The entire sphere be divided into infinite concentric spherical shells of thickness $dx$. Considering one such shell with radius $x$. volume of the spherical shell = $4πx^2dx$ charge ...
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2answers
25 views

Why do electric field lines point in the direction of decreasing electric potential?

Why do electric field lines point in the direction of decreasing electric potential? I came across this sentence in my school book but am trying to understand this ever since. I know that dV=-E.dr ...
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15 views

Two charged rods placed along the x and y axis respectively [closed]

Two charged rods of equal length $L$, $OA$ and $OB$, are placed along the $x$ and $y$ axis, respectively, $O$ being the origin. The rod $OA$ has a charge $+Q$ while the rod $OB$ has a charge $-4Q$. ...
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1answer
58 views

What is the electric field inside a hollow sphere?

If you have a conducting hollow sphere with a uniform charge on its surface, then will the electric field at every point inside the shell be 0. The reason the electric field is 0 at the center is ...
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1answer
58 views

Deriving Coulomb's law from quantum electrodynamics [duplicate]

Is it possible to derive the Coulomb's law using the principles of quantum electrodynamics? How?
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1answer
31 views

A solid non-conducting sphere of radius $R$ carries a non uniform charge distribution [closed]

A solid non-conducting sphere of radius $R$ carries a non uniform charge distribution with charge density $ ρ = k r/R$, where $k$ is a constant and $r$ is the distance from the center. Show ...
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3answers
29 views

A charge $Q$ is placed at a distance $a/2$ above the center of a horizontal square surface of edge $a$ [closed]

A charge $Q$ is placed at $a$ distance $a/2$ above the center of a horizontal square surface of edge $a$, while a second charge $Q$ is placed below one of the vertices of square. Find the flux of ...
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3answers
99 views

Can two electrons attract each other?

Due to electrostatic repulsion the two electrons will repel each other as they both possess similar charges, lets leave gravitational attractive force out of the picture my question is can there be ...
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0answers
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Density of polarisation charge is zero always for linear isotropic homogeneous dielectrics?

It seems to me that the volumetric density of polarisation charge in a linear homogeneous isotropic dielectric in an external field is always zero, but I find this rather surprising. Consider such ...
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2answers
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How can we prove that electric field originate from and terminate on charge using Gauss Law?

We already know that electric field originate and terminate on charge only and they doesn't make any closed path. But is it possible to prove this statement using Gauss Law ? If yes then how ?
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Current Density Boundary Conditions and its Implications

According to Ohm's Law, one can say $ \overline{J} =\sigma \overline{E} $ if the field is in a conductor, and $ \overline{J} =0 $ if it's in empty space. Now if we take the surface of a conductor and ...
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3answers
48 views

Parallel-plate capacitor working voltage $V={Qd\over{\epsilon_0 A}}$ relationship with plates' distance

I don't understand why the working voltage of a capacitor increases with the plates' distance. Suppose we have 2 capacitors in series where $C_1=12,0\mu F$ and $C_2=4,0\mu F$. The voltage over both ...
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0answers
28 views

Electric Flux through cube [closed]

There is a cube with a charge at one of it's vertex(say A). What is the total electric flux and the flux through each face? I know the answer but not the solution. I don't think gauss law would help ...
2
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1answer
24 views

Repel air by electrostatic charge

It is known that an electrostatically charged object can repel or attract a flow of water. Can this also apply to an air flow? And if so, would it happen only due to the humidity via water molecules, ...
2
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1answer
31 views

Is it possible for two polarizable bodies to induce dipoles in each other in the absence of an external electric field?

If there exist two initially neutral bodies (say atoms) some distance apart, with no external electric field applied, can they induce dipoles within each other?
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3answers
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Does the equation CV = q break down when V is small or a wire is very long?

I'm trying to understand how the equation $CV=q$ relating the voltage difference and charge stored on a charged capacitor breaks down under extreme circumstances. In most problem statements that I'm ...
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2answers
59 views

Proof that work is the same whaever the path of approach for two charges

I have a quick question on a figure that outlines a proof. There is a stationary charge $q_1$ and is kept fixed. $q_2$ is moved to the same position along two different paths at a fixed distance ...
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1answer
40 views

What is the distribution of charge on two conducting spheres?

There are two conducting spheres of charges $Q_1$ and $Q_2$ and respective radii of $r_1$ and $r_2$ with center-to-center separation of $L$. Can the distribution of charge on each of the conducting ...
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1answer
27 views

single conducting plane and parallel conducting plane with opposite charge all have different Electric field but same Electric Flux?

Considering the electric field $\vec{E}$ created by an infinite conducting plane $M_1$ having surface charge density $\rho_s$ locate at xy plane at $z = 0$ with $\hat{a}_z$ as unit vector ...
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1answer
87 views

Real life physics problem: Why is my desktop computer affected by my plasma ball?

Note: this is strictly a physics question, not meant to be an advertisement I was running my desktop with a plasma ball on the side. The desktop has a touch screen enabled. I started to notice that ...
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1answer
40 views

What is the acceleration of a charged particle in uniform electric field [closed]

I would guess its $kC/r^2$, just like the in the context of gravitation, as one arrives at the acceleration due to gravity $g = GM/r^2$; but I am not sure.
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2answers
263 views

Why electric field inside charged conductor is zero in the electrostatic case

I am trying to understand the idea (or the fact) that most books introduce which is about the electric field inside a charged solid conductor Books tell that the field has to be zero everywhere ...
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0answers
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two questions about concept of voltage and electric field

1.when we talk about voltage of a point where there exists around it only two point charges then is its voltage equal $V_1$+$V_2$?(where these are resp. voltages of the point due to the two point ...
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1answer
17 views

electric field in hollow conductor

when we have a hollow conductor and we charge it then the quantity of charges and electric on and in inner surface of conductor material is zero and this is okay .But is the electric field also zero ...
0
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1answer
34 views

Electric field and Gauss law

If we take a Gauss surface S to calculate the electric field using Gauss law:$\int\epsilon\vec{E}.\vec{dS}=\sum(Q's\ inside\ S\ +$ $Q's\ on\ S\over2 $ $)$ then this field calculated $E$ is for ...
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1answer
26 views

Confused about voltage due to a point charge

If we have a point charge q then on any point around q we have electric field done by q on this point, and there exist voltage(potenial) of this point due to q which is work done by q to move +1c from ...
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1answer
44 views

Potential and Electric field

I'm trying to find the electric field from the potential and vise-versa but I'm having trouble I know the electric field of a ring with radius a and charge Q to be $$E=\frac{Qx}{4\pi ...
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1answer
27 views

why isn't the net force considered while calculating potential due to a system of charges?

The textbook I'm reading defines potential at a point as work done per unit charge by an external agent to move the test charge from the reference point to the point under consideration (without ...
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2answers
56 views

Using Gauss's law (differential form) on an infinite line of charge

I just read about Gauss's law in differential form and how to compute divergence. I worked out the $1/r^2$ field and got zero as expected! I was very happy. Then I thought the infinite line of charge, ...
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19 views

How do i prevent static electricity on my trampoline? [duplicate]

Every time i am on my trampoline, i get a nasty static shock when i get down. I have no idea how this is caused. How do i prevent this? My trampoline is a 8ft trampoline with a net surrounding it.
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1answer
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Equipotential inside a conductor ring, but how do I determine the value?

I was mapping the potential lines of 2 cylindrical electrodes - one at 0 V, the other at 5 V. I have a metallic ring midway between the 2 electrodes. I know that the electric field inside the ring is ...
1
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1answer
61 views

Why does the field of an electric dipole drop off as $1/r^3$?

Electric field of a point charge drops off inverse squarely but that of a dipole varies as $1/r^3$. Why the field drops off more quickly for a dipole?
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2answers
46 views

a question about work needed to move a charge towards another one [duplicate]

Consider two charges $q_1>0$ & $q_2>0$ separated by a distance $d_1$, and we want to move charge $q_2$ to a distance $d_2$ from $d_1$ where $d_1-d_2>0$. I need to calculate the work ...