Electric field Definition and 1000 Threads

In the textbook (Introduction to Electrodynamics by Griffiths), the problem in the attached image asks to find the electric field ##E## outside a dielectric. The problem consists of dividing the electric field into the one produced by the negative charges in the dielectric and another by the...

So in my textbook (Introduction to Electrodynamics by Griffiths) it said that inside a conductor, the electric field E would have to zero, since if it wasn't the free charges would move accordingly and create a electric field that cancels the original field. But in a question that soon followed...

Homework Statement I need help on solving this exercise : We have a ring of radius = ##a## uniformly charged (total charge = ##Q##) and on its axis a segment ##OA## (length = ##a## also) of uniformly distributed positive electric charges with the charge density ##\lambda'## and of total charge...

Homework Statement What causes electric field? What causes magnetic field? (I) stationary electric fields (II) moving electric charges (III) a changing magnetic field IV) a current-carrying wire Homework Equations E=F/q B=μI/2πr E electric field F elecric force Q charge B magnetic field I...

Homework Statement Given two very long lines each is charged with linear density +lambda Coulombs/meter. The two lines are separated by a distance of d metres. A) show the electric field E, at any point along one of the lines due to the other line is E = lambda/(2 (pi)(epsolon o)(d)) (Note...

Hello, I want to create a handheld electric field meter to measure the strength at a certain point with an arduino. I have seen various ideas online but I am still not sure what kind of design to use. Is the right concept to use two antennas. Measure the voltage on each and then calculate the...

Homework Statement In the file Homework Equations No equations needed The Attempt at a Solution I answered it C. Since I learned that at the tip there are most of the charges. Therefore, it’s the point of the greatest E field magnitude. But another tutor told me that it is a circle, and...

Homework Statement An electron and a proton are each placed at rest in an electric field of 687 N/C. What is the velocity of the electron 56.5 ns after being released? Consider the direction parallel to the field to be positive. The fundamental charge is 1.602×10−19 C, the mass of a proton is...

Homework Statement A charged cork ball is suspended on a light string in the presence of a uniform electric field. E=(3×10^5 N/C)i+(5×10^5 N/C)j. The ball is in equilibrium in the field. Find the charge on the ball. The acceleration due to gravity is 9.8 m/s2 . The mass of the ball is 0.7g. The...

Homework Statement Homework EquationsThe Attempt at a Solution I am having trouble figuring out why the answer is A) the electric field points radially between A and B. I think it is because since the point between A and B is mostly negative, the electric field would point outwords more...

Homework Statement determine the electric flow through a square surface of side 2l due to a load + Q located at a perpendicular distance l from the center of the plane I really don't know how to answer this question .i need help guys Thanks Homework EquationsThe Attempt at a Solution I ended...

Homework Statement Consider a spherical shell with uniform charge density ρ. The shell is drawn as a donut with inner (R1) and outer (R2) radii. Let r measure the distance from the center of the spherical shell, what is the electric field at r>R2, R1<r<R2, and r<R1. I am working on the r > R2...

Homework Statement A) Use Gauss's Law to derive the electric field in all space for a non-conducting sphere with volumetric charge distribution ρ=ρ0r3 and radius, R. B) Repeat when there is a concentric spherical cavity within the non conducting sphere with radius, A. Homework Equations...

Homework Statement A spherically symmetric charge distribution produces the electric field E=(200/r)r(hat)N/C, where r is in meters. a) what is the electric field strength at 10cm? b)what is the electric flux through a 20cm diameter spherical surface that is concentric with the charge...

Homework Statement A spherical cavity is hollowed out of the interior of a neutral conducting sphere. At the center of the cavity is a point charge, of positive charge q. (picture attached) a)What is the total surface charge q(int) on the interior surface of the conductor (i.e., on the wall of...

Homework Statement Two small insulating spheres with radius 9.00×10−2m are separated by a large center-to-center distance of 0.545 m . One sphere is negatively charged, with net charge -2.35 μC , and the other sphere is positively charged, with net charge 4.35 μC . The charge is uniformly...

Homework Statement The figure below shows a thin, vertical rod of length L with total charge Q. The indicated point P is a horizontal distance x from the one end of the rod. What is the electric field at point P. Express your answer in component notation in the two blanks below. L = 5.0 cm, Q...

Homework Statement The figure below shows a thin, vertical rod of length L with total charge Q. The indicated point P is a horizontal distance x from the one end of the rod. What is the electric field at point P. Express your answer in component notation in the two blanks below. L = 5.0 cm, Q...

Homework Statement What is the magnitude and direction of the electric field at the position indicated by the dot in the figure below? Give your answer in component form in the blanks below. What is the x-component of the electric field at the indicated point? Homework Equations kq/r^2 The...

Homework Statement Before diving into the quantum-mechanical superposition principle, let’s get some practice with superposition in classical physics. Consider an electromagnetic wave propagating in the z-direction, which is a superposition of two linearly polarized waves. The electric field...

Homework Statement You are given a non conducting rod carrying uniformly distributed charge, -Q, that has been bent into a 120° circular arc of radius, R. The axis of symmetry of the arc lies along the x-axis and the origin is at the center of curvature of the arc. (a) in terms of Q and R...

Homework Statement Derive the electric field a distance, z, above the center of a single uniformly charged ring of radius, R, with a linear charge density, λ. You are now given two uniformly charged concentric rings. The inner ring has radius, R, and carries a uniformly distributed total charge...

Homework Statement At what distance, a, along the axis of a uniformly charged disk of radius R is the axial electric field strength equal to one half its value at the surface of the disk at the center. Homework Equations electric field of disk (attached) The Attempt at a Solution First I...

Homework Statement Homework Equations charge density equations, electric field equations, The Attempt at a Solution My attempts are attached. The attachment labeled A, is part A. Part B took a lot of paper so there are two attachments labeled B1 and B2. It is really B and C that I am...

Homework Statement A proton enters the uniform electric field produced by the two charged plates shown below. The magnitude of the electric field is 4.0 × 105 N/C, and the speed of the proton when it enters is 1.5 × 107 m/s. What distance d has the proton been deflected downward when it leaves...

An insulating spherical shell of inner radius r1 and outer radius r2 is charged so that its volume density is given by: ρ(r) = 0 for 0 ≤ r < r1 p(r) = A/r for r1 ≤ r ≤ r2 p(r) = 0 for r > r2 Where A is a constant and r is the radial distance from the center of the shell. Find the electric...

I have a PhD in Molecular Neuroscience but am working on something that requires knowledge of electric field distribution in the brain. I understand that electric field intensity (V/cm) is E=(V1-V2)/d in a theoretical model (between 2 infinite plates, that are parallel and equidistant through a...

Hi, I have a PhD in Molecular Neuroscience but am currently working on something that requires a deeper understanding of electric field distribution in the brain. I joined the forum hoping to be able to discuss this topic with a fellow scientist who specializes in this field.

Homework Statement A solid isolated sphere with radius R has a non uniform charge which is given by ρ= Ar², with A a constant and r<R measured from the centre of the sphereHomework Equations (a) Show that the electric field outside the sphere is equal to E = (AR5)/(5ε0r²) (b) Show that the...

Hi, I have difficulty understanding the term screening. Screening is reducing of the electric field, as far as I have understood until now. 1. Why does screening occurs? Is it due to collective interaction of plasmons? 2. If we have a slow electric field, will screening occur or will it not...

The lower plate of a parallel plate capacitor is supported on a rigid rod.The upper plate is suspended from one end of a balance.The two plates are joined together by a thin wire and subsequently disconnected.The balance is then counterpoised.Now a voltage V= 5000V is applied between the...

Homework Statement There is a uniform electric field=100 V/m inclined at 45 degrees with the x axis. My doubt boils to which is greater? V(0,0) or V(10√2,0) (since my answer has the wrong sign) Homework Equations All electrostatics formulas The Attempt at a Solution The work done to move a...

Homework Statement A solid non-conducting cube of side l and uniformly distributed charge q, has electric field E and potential V at one of its vertex, imagine this cube to be made of 8 smaller cubes of side l/2. if one such cube is removed, find the new field and potential at the point where...

Homework Statement Two infinite sheets of charges are placed parallel to each other. If the sheet on the left is non conducting and have a uniform charge density 3(sigma) and the one on the right is conducting and has a uniform charge density (sigma). If the area on both plates is 1m^2 then...

Hi, I was reading the capacitor and its operation and it is written there that when the DC is applied to the capacitor it becomes open circuit. The main mechanism behind this phenomena is explained as below:- "When DC voltage is applied the charge started accumulating on the plates of the...

The Faraday's law and Lenz's law together give you, $$\xi = -\frac{\partial\phi_B}{\phi t}$$ or put another way,$$\vec{\nabla} \times \vec{E} = -\frac{\partial \vec{B}}{\partial t}$$. My question, I am just asking to make sure, the spatial dependence of ##\vec \nabla \times \vec E## will be the...

Homework Statement A long, thin, straight wire of length 1.3 m has a positive charge 4.1 × 10-8 C distributed uniformly along it. The electric field created by this wire at a radial distance 3.2 cm has a magnitude of ε= 8.85E-12 Homework Equations I think I need to use E= q/(4πr^2ε) but I...

I have some understanding, but I'm not sure about how accurate it is: Electrostatic force is given by F = qE, where F and E are both vector quantities. If the dot product of either side and the displacement vector Δs along an equipotential line is taken, the equation becomes F⋅Δs = qE⋅Δs. F...

Hi everyone, I often work on a SEM, a type of microscope which is based on electron acceleration between an electron source and the sample you are working on. For this reason and since a few weeks I was wondering how an electron (in term of speed) behaves in a constant and linear electric field...

I would very much appreciate a clarification on what is meant by a changing electric field in the context of statements such as 'a changing electric field creates a changing magnetic field'. My question is does the electric field actually need to reverse as a lot of examples show where two...

The Faraday effect is a magneto-optical phenomenon caused by the interaction between light and a magnetic field. Is there a corresponding electrical-optical phenomenon, caused by the interaction between light and an electric field?

I need a little help here when calculating the work done in a uniform electric field on a positive charge to move it from point a at higher potential to point b at lower potential that means the charge is going towards the negative plate we first use V = - ED and then we have a...

If I try to calculate the electric field in the x-y plane of a ring of charge resting at the origin on the x-y plane, I keep getting zero. I start with Coulomb's Law. $$ dE(r) = \frac{1}{4\pi\epsilon}\frac{dq}{r^2} = \frac{\lambda R}{4\pi\epsilon}\frac{d\theta}{r^2},$$ in which ##\vec R## is...

Hello! I am reading about image charges for an infinite plane and a charge above the plane. In the book I am reading (Griffiths) the author says (and uses this results several times) that the field below the plane is 0. How do we know this? The method of the mirror charges gives the V above the...

1. Problem Statement: Find positions on the x-axis for the charges Q1 = -1 C and Q2 = +3 C so that the electric field is zero at x = 0. Homework Equations :[/B] I'm thinking I need to use Coulomb's law for this one. I'm just having trouble figuring out where to start. Coulomb's states E=kQ/r^2...

Hi there Only known variables include the solar flux on the Earths atmosphere at the equator is 1.5 kWm^ -2. I've calculated the total energy from the Sun as 4 x 10^26 W, but can't seem to get to a calc of the mag of electric field at equator (measured in kVm^-2).

Homework Statement Two charged balls are placed in point A and B and the distance between them is 9,54cm. Each of the balls are charged with 8,0 x 10^-8 C. Find the scalar value and direction of the electric field in point C placed 5 cm from A and 6 cm from B. Homework Equations Cosine Rule...

Homework Statement Homework EquationsThe Attempt at a Solution I know the units for V is J/C so #3 and #4 are wrong. But how do I determine the signs?

Outside the battery, in the conductor it is in the direction of conventional current. But what about inside? Since magnetism and electricity are related, and magnetic field inside a magnet is from South to North (outside it is North to South), i doubted for any correspondence.

Homework Statement Calculate the electric field given by a voltage drop of 1 V across an insulator with thickness 20 nm. 2. The attempt at a solution I am not sure which formula to use in order to obtain the electric field. I think one should use the formula E=U/d, where E denotes the...