Electrostatics Definition and 685 Threads

A point charge q is placed at a distance 2r from center O of a conducting charged sphere of radius r .Due to the induced charges on the sphere ,find electric potential at point P on surface of sphere [if Kq/r=18V] I tried this at point P Vnet=Vinduced+Vcharge now Vcharge=kq/3r but I cannot find...

I just have a few conceptual questions: Is it as difficult to remove electrons from an insulator as it is to add to it? I understand insulators have a lower permittivity than conductors, and that they still allow charges to build upon the surface. However, I read that when you rub an insulator...

Electromagnetism is divided into two parts Electrostatics Magnetism Therefore I want to know what are the main difference between electrostatics and magnetism with their examples in layman terms because I am not at all introduced to this concept but I want to know the general concepts related...

Homework Statement Lets say, there is a non-uniform charge distribution, given as in a spherical shell that has a cavity with radius a and the radius b to the outer surface. I am wondering if the field is discontinuous just on the surface of this sphere. Homework Equations...

My Approach is shown in the picture.

I was doing some T/F exercises and there was this one that had me confused: The potential of a negatively charged conductor must be negative Because it's conductor, i figured all of the conductor would be negatively charged and so it would have a negative potential, but apparently this...

Homework Statement Four point charges are placed at the corners of a square of side 1m as shown in Fig 18.54 Find a) the electric field, and b) the electric potential at the center of the square Photo is attached Homework Equations coulomb's law Ans of a=76.3 x 10^3 NC^-1 upward Ans of...

Homework Statement On a long friction-less non-conducting straight needle are threaded an infinitely large number of identical beads.The beads are made of insulating materials and have charges of equal magnitude and alternate plus and minus signs.Assume charge distribution on a bead unaffected...

Hello. I have a doubt regarding the direccion of the electric field in a point from a source charges. Let be a charge in the left of the plane. In a point to the right of the charge, the direction of the electric field vector is to the right. If the charge is negative, the direction of the...

Homework Statement We model the Hydrogen atom as a charge distribution in which the proton (a point charge) is surrounded by negative charge with the volume density of ρ = -ρ0 * exp (-2r/a0) where a0 is the Bohr radius. And ρ0 is a constant chosen such that the entire atomic distribution is...

Homework Statement The geometrical positions of point-like charges and point A situated in the xy-plane in terms of the length parameter a. The vector of electric field E at point A is shown schematically and measured as E = Exi + Eyj (that is, both Ex and Ey are given). If possible, find the...

Hello. Well, each and everyone of us know that Like Charges repel, while unlike charges attract. That's a normal high school physics fact. But what's the reason for that? Is it just an experimental fact, or even does have theoretical significance? Please do help. Thanks a lot Swapnil Das.

Homework Statement two infinitely large plates are at a distance d from each other .they carry a unifor surface charge of densities X and -X.the plates have round coaxial holes of radius R.with d<<R.find the electric field through the axis of the holes(taking them as circles) as a function of...

Homework Statement A charge 2Q is placed a distance 'd' from charge 4Q. A third charge 'q' is placed 3m from charge 2Q directly on the line between charges 2Q and 4Q. Find d and q such that the force between charges 2Q and 4Q is equal to 0. Homework Equations Coulomb's law: f = k(|q1q2|)/r2...

Homework Statement A spherical capacitor comprises two thin metal spheres of different radii but with a common centre. The following series of operations is completed: The spheres are mutually connected by an internal wire. The outer sphere is raised to potential +V with respect to ground. The...

Here's a random thought that I don't as yet have a satisfactory solution: Let's assume we have a copper column resting on an insulated table. Copper is an electric conductor, which means that some electrons within the copper column move freely throughout the column, subject to electromagnetic...

Homework Statement I am not sure whether to put this in the introductory level or advanced. It seems to be relatively introductory in an electromagnetism course. A spherical conductor of radius ##a## carries a charge ##q##. It is situated inside a concentric spherical conducting shell of...

On applying definite integral to find work done, we integrate F.dx and apply lower and upper limits. Should we apply the dot product, before integration , that is -1 for θ = 180, 1 for θ = 0. Or will the limits applied and their values suffice in deciding the sign of the final value. I have...

Why doesn't the flux through a Gaussian surface change, when the shape is changed? (while keeping the net charge inside it the same) Flux is the dot product of electric field and surface area, so wouldn't it change if surface area is changed?

On calculating the electrostatic potential at a point due to charge q, by definition, it is the work done to bring a unit positive charge from infinity to that point. Trying to find it mathematically, it should be ∞→R ∫E.dr...

For a system of 'n' parallel plates(metal plates) bearing charges q1, q2,... qn ; why it is so that the facing surfaces of the plates bear equal and opposite charges ? How do we prove that ?

Homework Statement An uncharged capacitor is connected to a charged capacitor as shown: The ends are left as it is. Will the charges redistibute? Homework Equations None The Attempt at a Solution I think it won't. Let the first capacitor be charged with charge Q. Before closing the switch...

Homework Statement A positive point charge q is located off-center inside a conducting spherical shell.We know from Gauss’s law that the total charge on the inner surface of the shell is −q. Is the surface charge density negative over the entire inner surface? Or can it be positive on the far...

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 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...

Hello, I'm taking a course in electrostatics and electrodynamics. We learned about finding a potentional using unique Green functions that are dependent of the geometry of the problem. Specificly on a Dirichlet problem we get the solution: Φ(x)=∫ρ(x')G(x,x')d3x' -...

Laplacian for polars: $$\frac{1}{r}\frac{\partial}{\partial r}\left( r\frac{\partial \phi}{\partial r}\right) + \frac{1}{r^{2}}\frac{\partial^{2} \phi}{\partial \theta^{2}} = 0$$ This is in relation to a problem relating to a potential determined by the presence of a wedge shaped metallic...

Homework Statement How much work (in J) is required to bring a charge of 2 microC from the point {2*6.8,-7,2*1.1}cm via the point {10,20,1}cm to the point {-3*6.8,3.4,-3*1.1}cm, in a medium with relative permittivity of 3.7, near a line charge along x=6.8 cm, z=1.1 cm, with charge density +329...

Homework Statement How do I find the total charge from a material with a charge density given by \rho =10^{-9} \text{cos}\left ( \frac{z}{z_0}\right ) C/m^3 that exist between \frac{-\pi}{3}z_0<z<\frac{\pi}{3}z_0. Homework Equations None I can think of. The Attempt at a Solution Attempt #1...

Homework Statement There protons are and two positrons are held such that two protons are on the ends of a diagonal of a square and the two positrons are on the ends of the second diagonal. The third proton is situated at the centre of the square. The system is released from rest. Find the...

Homework Statement Two protons in an atomic nucleus are typically separated by a distance of 2x10-15 m. The electric repulsion force between the protons is huge, but the attractive nuclear force is even stronger and keeps the nucleus from bursting apart. What is the magnitude of the electric...

Homework Statement Based on a lab we did at school, we charged a Styrofoam plate by rubbing it against wool and determined that it attracted pieces of paper but repelled pieces of aluminum foil. Can anyone clarify why this is because I believe that both the pieces of paper and aluminum foil are...

Homework Statement A charge distribution has uniform density in the x-y directions and varies with z according to: ρ(z) = ρ0e−|z|/t where ρ0 and t are constants. (a) Find the potential V (z) and the electric field E(z) (b) Sketch them clearly showing their behaviors in the regions |z| ≪ t...

In a --specifically uniform electric field-- (I may be wrong here) my understanding is that the dipoles will result in no net dipole force (due to cancelling out) but there will actually be a net torque experienced about the center. This torque will be trying to turn the dipole so the moment, p...

I was wondering if you could help me explain a physics problem. The topic is Electrostatics: We have two objects that attract each other and the distance between them is r and the force is F1. Then we put those two objects together and then put them back to the same distance as before (r). Why...

in deriving the capacitance of a parallel plate capacitor why do we take the field between the capacitors as σ/∈ and not 2σ/∈,when there are two plates and in the region between the capacitors, field must add up so shouldn't it be 2σ/∈?

Homework Statement while solving a problem i got a doubt from one of the steps, there are 2 metal spheres ,distance between them is l.the charges present on the sphere and radii are q1,r1 and q2,r2 respectively. now we have to find the potential on sphere 1 due to 2 and on sphere 2 due to...

Homework Statement Please see this illustration http://www.physicsgalaxy.com/lectures/1/57/1006/Solved-Example-1#6 (see question only) Homework Equations potential due to a hollow sphere at it's centre = kq/rThe Attempt at a Solution here won't there be an induced positive charge on the outer...

Homework Statement A metallic sphere is placed inside a hollow spherical shell. The potential on the inner and outer spheres is 10 V and 5 V respectively. What is the potential at the center?(The spheres are concentric.) Homework Equations $$V =\frac{kq}{r}$$ The Attempt at a Solution The...

Hello , I post a message because I will need help with this exercise I would like to knowif my answer are good, I'm french : An infinite hollow cylinder charge is constituted of a sheath whose outer limits are R2 and R3. Wearing a uniform charge density ρ Question 2)calculate the total...

Hello. I have a problem calculating the electric field from spherical charge distribution. The exercise is: 1. Homework Statement Homework Equations To solve the problem for $$ 0\le R < a$$ i tried 2 ways: $$ \vec{E} = \frac{\vec{a_R}}{4\pi\epsilon_0}\int_v\frac{1} {R^2}\rho dv $$ and the...

Homework Statement A cone of height H and base radius A is charged with charge Q uniformly distributed in all its volume. Find electrostatic field intensity at the top of the cone. DATA: H, A, Q Homework Equations E=ρ/(4πε0) ∫Ω dΩ/R2) and R is a vector (rr^+zz^) r^ and z^ are versors The...

Homework Statement A parallel plate capacitor was lowered into water in a horizontal position, with water filling up the gap between the plates (gap d=1.0mm). Then, a constant voltage V=200volt is applied to the capacitor. Find the increment of pressure in the water between the gap. Homework...

Homework Statement Show the the induced charge density on a dielectric placed inside a capacitor is given by $$\frac{k-1}{k}\sigma$$ where ##\sigma## is the charge density of the capacitor plates and ##k## is the dielectric constant. Homework Equations $$E=\frac{E_0}{k}$$ The Attempt at a...

Homework Statement What charges will flow after shorting of the switch (Sw) in the circuit below through sections 1 and 2 in the direction indicated by the arrows? Homework Equations Kirchoff's laws The Attempt at a Solution Initially, both capacitors will have a charge of...

Homework Statement Consider two solid dielectric spheres of radius ##a## separated by a dis- tance ##R## (##R\gg a##). One of the spheres has a charge ##q## and the other is neutral. We scale up the linear dimensions of the system by a factor of two. How much charge should reside on the first...

If there is a small object with positive charge placed above a metal plate, the object induces a negative charge on the surface of the plate facing the object. Let's call this surface as S1. (The metal plate is initially uncharged). But from conservation of charge, the net charge in a metal...

Problem: Consider two parallel and large sheets with a surface area . One has a charge and the other is uncharged. q | | | | | | | | | | What would be the electric fields on the three regions as divided by the sheets ? General solution to problems like as told...

Homework Statement Find Electric field at center of charged hemispherical shell Homework Equations In spherical coordinates, $$dA=R^2\sin\phi d\phi d\theta$$ The Attempt at a Solution From the image, Enet=2dEy=2dEcosφ $$dE=\frac{kdq}{R^2}E$$ $$dE=\frac{k\sigma dA}{R^2}$$ $$dE=\frac{k\sigma...

Homework Statement If ##\vec{E}=k\frac{x\hat i +y\hat j}{x^2+y^2}##, find flux through a sphere of radius R centered at origin. Homework Equations ##\int E.da=\int(\nabla\cdot E)\cdot da## The Attempt at a Solution I was able to solve this problem without finding divergence of electric field...