Electric field Definition and 1000 Threads

Homework Statement Calculate the magnitude of the electric field at the center of a square 42.5cm on a side if one corner is occupied by a −38.2μC charge and the other three are occupied by −26.9μC charges. (This part done) Choose the correct direction of the electric field at the center of...

I am trying to find the electric field of a hollow, open-ended, thin-walled cylindrical conductor. I am trying to solve something regarding LINACs: Assume we have an isolated, hollow, open-ended, thin-walled cylindrical conductor, with a net charge. The net electric field within the...

Homework Statement Two concentric cylindrical conducting shells of length L are separated by a vacuum. The inner shell has surface charge density +σ and radius ra. The outer shell has radius rb. Using Gauss’ Law, as a function of radius r find: The direction and magnitude of electric field...

Homework Statement Homework Equations E = kq/r2 V = -∫ E ⋅ ds W = -Vq The Attempt at a Solution a) I just summed up the electric fields: +ek/a2 +ek/a2 -ek/a2 so I get +ek/a2 as a result. Not sure if this is correct since -e has a y component so I was thinking to use sin but not sure which...

Need help with Problem 1 Homework Equations E = kq/r2 V = -W/q V = kq/r The Attempt at a Solution 1a. dE = kdq/rRSUP]2[/SUP] dq = p ds dE = kpds/R2 Not sure if I am right up to this point and don't know how to proceed. 1b. I think the electric field would be zero since the enclosed charge...

Homework Statement Hi everybody! I might have solved that homework but I struggle to properly understand some steps, especially concerning the gradient and partial differentiation: The potential Φ(r) of an electric dipole located at the origin of a coordinate system is given by: \phi...

Homework Statement A straight circular plastic cylinder of length L and radius R (where R ≪ L) is irradiated with a beam of protons so that there is a total excess charge Q distributed uniformly throughout the cylinder. Find the electric field inside the cylinder, a distance r from the center...

Ques: If infinite number of charges placed along x-axis .At x=1, 1μC , x=2, 2μC, x=3, 3μC so on. Find the net force on charge 1μC placed at origin.Formula used (1/4πε)*q1*q2/r² Solved from this formula but stuck in a series

Homework Statement A metallic hollow cylinder has a diameter of ##4.2 cm##. Along his axis there is a wire having a diameter of ##2.68 \mu m##(considering it as a hollow cylinder). Between the cylinder and the wire there is a voltage of ##855 V##. What is the electric field on the wire surface...

Homework Statement What electron current is driven through a 1.4-mm-diameter iron wire by a 0.070 V/m electric field? The mean time between collisions in iron is 5.2×10^−15s . A=1.5*10^-6 m^2 ne=8.5*10^28 m^-3 Homework Equations I know I need to use ie = neAVd, but I'm having trouble finding...

Homework Statement Hi everybody! Here I am with another problem of electromagnetism, I'd like to make sure I understand it properly! An electron is moved 1 meter towards an homogeneous electric field of strength 1N/C. How big is the work done for this motion? Homework Equations F = q \cdot...

Homework Statement We have a wire of the length L=0.2m which is uniformly charged with a linear density of Lambda = 3nC/cm. Find the intensity (E) of the electric field in point A1 whose perpendicular distance from the wire is a=0.05m. The wire is in a vacuum. Compare the intensity with the...

1. Homework Statement Why is there no electric field strength in a metal sphere? Is it because the sum of the individial electric field strength of the charges in the sphere is zero? How is that possible? Homework EquationsThe Attempt at a Solution

Homework Statement A charge is distributed evenly along the ##z## axis with a density ##\lambda = 3 \frac{\mu C}{m}##. There is also a cylinder with radius ##r = 2## and on his side there is a superficial density charge of ##\sigma = -\left( \frac{1.5}{4 \pi} \right) \frac{\mu C}{m^2}##. Both...

When a plane sheet is given a charge Q the electric field at any point around it is given as ##E = \frac{\sigma}{\epsilon_0}##. Thus mathematically it can be concluded that the electric field is constant everywhere and is independent of distance of the point from the sheet. But what logical...

Homework Statement A volumetric charge density ##\rho = \frac{A}{r}## is distributed in the spheric region ##r_1 < r < r_2## (##A## is constant). A point charge ##q## is located in the center of the sphere (##r = 0##). What should be the value of ##A## so that the module of the electric field...

Hi guys. This is my question. I just wondering what equation that I'm suppose to use. Homework Statement What is the maximum distance at which a shark can detect the electric signal emitted by the trout’s heart if the predator is at a point on an axis passing through the centre of the heart...

(sorry for my poor english) I've read that a electromagnetic wave only exists in a particular point of space if in such a point there is a nonlinear change of the electric field in respect to time. Then I took a graph calculator and I derived Coulombs equation for the electric field. The results...

Homework Statement A thin insulating rod with charge density lambda=+5nC/m is arranged inside a thin conducting cylindrical shell of radius r =3 cm. The rod and the shell are on the same axis, and infinite in length. What is electric field at point p? 6cm from the central axis. Homework...

Homework Statement It is not an actual questions, Just misconceptions For example, Lets find the work done over a distance in an electric field Homework Equations v = PE/q E = F/q F = k q1 q2 /r^2 W = fd The Attempt at a Solution I didn't study calculus yet but I am going to because I need to...

Homework Statement A thin rod of length 2L has a linear charge density that isλ0 at the left end but decreases linearly with distance going from left to right in such a way that the charge on the entire rod is zero. Given E = −kλ0/L(d/(L−d)−ln(d−L)+d/(L+d)+ln(L+d)) for a point P that is...

Homework Statement You wish to determine the electric field magnitude along the perpendicular bisector of a 230-mm line along which35 nC of charge is distributed uniformly. You want to get by with a minimal amount of work, so you need to know when it is sufficient to approximate the line of...

Homework Statement In the "Before" scenario, there is conductive plate in electrostatic equilibrium with uniform surface charge density +η (the plate has some thickness but the width and length are significantly larger). In the "After" scenario, an infinite plane of negative charge with fixed...

Homework Statement A positively charged particle initially at rest on the ground accelerates upward to 180 m/s in 2.70 s .The particle has a charge-to-mass ratio of 0.100 C/kg and the electric field in this region is constant and uniform. What are the magnitude and direction of the electric...

I know that energy stored in electric field / unit volume = 1/2 ε E2 so can I say that for any configuration calculating ∫ ½ ε E2 over whole space - gives me the potential energy stored stored in the system for instance for → Q1 °...

Homework Statement Find the force that tries to rip apart a conducting shell into two halves about its equator when kept in a uniform electric field of magnitude ##E##. Homework Equations Gauss Law: $$\nabla\cdot\vec{E}=\frac{\rho}{\epsilon_0}$$ I think Laplace equation might also be...

Homework Statement A positive charge of 3 microCouloumbs is at the origin. A negative charge with the same magnitude is 8 m away along the x direction. a) What are the magnitude and direction of the electric field at the points between the two charges, 2, and 4, and 6m from the positive charge...

Homework Statement Suppose we have a rod of length L oriented on the z-axis so that the bottom end is at z= - L/2 and the top end if at z = L/2. Furthermore, the rod is uniformly charged with charge density 'λ'. Now we are interested in finding the electric field at a point x away from the...

Dear All, I know this may sound a bit of a broad approach for a question but I would like to know what equipment I would need to create a very high electric field in order to levitate a non-highly conductive droplet (from water to water + salts but not metallic, in the milli-microscale). I will...

Homework Statement I just want to focus on the divergence outside the cylinder (r >R) Homework Equations The Attempt at a Solution For r > R, I said ∇ * E = p/ε But that's wrong. The answer is ∇ * E = 0 I'm confused because there is definitely an electric field outside the cylinder (r...

Homework Statement Using direct integration, compute the electric field at the point (0,0,Z) of a semi-espherical (z > 0) charge distribution of radius R < Z and density ##\rho=constant## having a spherical hole of radius ##r_h<R## centered at (0,0,##r_h##). Homework Equations Coulomb's law...

Homework Statement A circular rod has a radius of curvature R = 8.11 cm, and a uniformly distributed positive charge Q = 6.25 pC and subtends an angle theta = 2.40 rad. What is the magnitude of the electric field that Q produces at the center of curvature? Homework Equations E = kQ/r^2 6.25 pC...

Homework Statement A metal sphere of charge +6μC is surrounded by a metal shell of net charge +6μC. Which of the following diagrams represents the electric field lines of the system? Homework EquationsThe Attempt at a Solution The correct answer provided by my teacher is a figure with 12...

If an electron in an excited wave form passes thru an electric field , can it lose kinetic energy in doing so.?

As the name of the thread says, I am wondering what would the amount and the direction of the electric field at some point in the uniformly charged ball of radius R(it has a constant charge volume density) be at the distance r from the centre of the ball. Does anyone know what would they be? I...

I don't know why I was persuaded that in the free space, the electric field of an EM wave is always orthogonal to the direction of propagation. I've recently read my old textbook, and found that this is true only when the wave is far from the emitting source. But if I've understood right the...

Homework Statement Two parallel plates at -50kV and 100kV have separation 35cm. a proton is placed between the plates. calculate the electric field strength between the plates Homework Equations E=v/d The Attempt at a Solution 100kV--50kV=150kV 150x10^3/0.35=428571.4N/C

Homework Statement Given that the potential of dipole is equal to: V(\vec{r})=\frac{\vec{p}\vec{r}}{4\pi\epsilon_0 r^3} show that the electric field is equal to: \vec{E}(\vec{r})=\frac{1}{4\pi\epsilon_0}(\frac{3(\vec{p}\vec{r})\vec{r}}{r^5}-\frac{\vec{p}}{r^3}) Homework Equations...

Suppose there is a metal disk with an initial excess of charge represented by the four red electrons. Naturally, they reach their equilibrium position on the surface. After this, a new electron (the green one) is added exactly at the center. The repelling forces from the red charges cancel each...

Homework Statement In the figure (attached), find the magnitude and direction of the electric field at points A, B, C and D. Homework Equations E = kQ / r^2 The Attempt at a Solution I'm just a little lost with the directions/if I need to be including angles so for point A: E = k 7.5e^5C /...

Homework Statement An electron has an initial velocity of 5.00 x 10^6 m/s in a uniform 2.00 x 10^5 N/C strength electric field. The field accelerates the electron in the direction opposite to its initial velocity. (a) What is the direction of the electric field? (b) How far does the electron...

When we looked at some closed surface, we defined the overall electric flux of that surface as the sum of all infinitesimal fluxes of all the infinitesimal surfaces that make the quoted closed surface. Does that change if we do not have a closed surface, but a rigid body such as, let's say, a...

What is electric field distribution around two conductor cable connected to DC power supply? Assume power supply is isolated and not grounded. Assume cable is straight. Case 1: no current runs through the cable. One wire is positive, another – negative. Negative or zero? If we think in terms of...

This is from Jackson, "Electrodynamics" a field is a fuction mapping phi: M -> T, x -> phi(x) from a base manifold M into a target manifold T. field X: R3 * R1 -> R3 x(r,t) ->X(x)I think this is eucledian R4 to R3 so I wonder why Jackson explained this with the concept of manifolds? Is it...

Homework Statement Two charged plates are 2mm apart. An electron escapes from the negatively charged plate and reaches the positively charged plates in 1.2x10^-8 seconds. Find the electric field between the plates. Homework Equations E=V/d eV= + or - 1.6x10^-19 C The Attempt at a Solution...

Homework Statement Consider two balls of equal radii and masses but opposite charges, distributed uniformly over their volumes. Initially, the balls are at rest and far away from one another. Due to the Coulomb attraction, the balls start moving towards each other. The balls can be treated as...

Hi people, I don't understand why when we apply the electric field to the metal Ef remains the same. Ef as translation energy of electrons remains the same but we accelerate the electrons with applied electric field so the translation energy increases too? In other hand according the formula...

Homework Statement My teacher came yesterday, and put in the board one exercise, just the scheme, not aditional data, i have one picture of the scheme Homework Equations The given E its mean to electric field The Attempt at a Solution I need some help, go get the right way into problem [/B]

Homework Statement In the below figure, magnetic field is decreasing at a rate of 1.5T/s in a circular region of radius 2m. EMF developed in the rod will be? Homework Equations $$V_{\text{induced}}=-A\frac{\mathrm{d}B}{\mathrm{d}t}$$ The Attempt at a Solution I tried using induced electric...

Homework Statement beam of protons moving in +x direction at speed v electric field is perpendicular to magnetic field magnetic field in +y direction no deflection What direction/sign has the electric field? Homework Equations not looking for numerical solutions The Attempt at a Solution...