Electrostatics Definition and 665 Threads

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...

Problem: When a dielectric slab is inserted between the plates of one of the two identical capacitors in Fig. 25-23, do the following properties of that capacitor increase, decrease, or remain the same: (a) capacitance, (b) charge, (c) potential difference (d) How about the same properties of...

Homework Statement Consider solutions to the One Dimensional Laplace's Equation in Cartesian Coordinates Let the range of x be from x1 to x2 (x1 > x2) and the boundary conditions are V[x1] = V1 and V[x2] = V2 Find the equation for V[x] Homework Equations V[x] = 1/2 (V(x+a)+V(x-a)) V[x] = mx...

Homework Statement A point charge e is braught near a spherical conductor of radius "a" having a charge "q".show that the particle will be repelled by the sphere unless its distance from the nearest point of its surface is less than (a/2) *√(e/q) approximately? Homework EquationsThe Attempt at...

Homework Statement 1. Compute the electric field vector at the position of charge B for the case where q_{A}=4q_{C} and r_{1}=2r_{2} 2. Suppose that all three charge are positive and that q_{A}=4q_{C} . Consider the case where f q_{B} is moved to the right by a distance dr. Now r_{1} = 2r+dr...

My first homework for electrostatics course I'm taking is to find the vector of electric field of a completely hollow sphere (radius r, surface charge density σ in a point A, by integrating the electric field through the whole sphere. I already figured out the electric field of a ring in a point...

Homework Statement A positively charged wire is bent into a semicircle of radius R, as shown in the figure below. The total charge on the semicircle is Q . However, the charge per unit length along the semicircle is non-uniform and given by λ=λocos(θ) What is the relationship between λo, R...

Homework Statement You are studying Gossamer Spiders in a biology research lab and marvel at their ballooning stunts. These Spiders disperse by spinning strands of silk in open air. The flight of these spiders is electrostatic in nature because everything that moves through air develops static...

Homework Statement In inkjet printing, a rapidly moving nozzle horizontally squirts drops of ink that form letters and images on paper. A common problem is horizontal white lines running through the print due to a clogged nozzle. Another common problem is paper dust. (a) Within the context of...

Homework Statement The problem puts forth and identity for me to prove: or . It says that I can use "straight-forward" calculation to solve this using the definition of nabla or I can use Gauss's and Stoke's Theorum on an example in which I have a solid 3D shape nearly cut in two by a curve...

Homework Statement A closed curve C is described by the following equations in a Cartesian coordinate system: where the parameter t runs monotonically from 0 to 2π, thus defining the direction of C. Calculate the area vector of the planar region enclosed by C, using the formula: 2. The...

Homework Statement Essentially it gives the potential above the xy-plane as and I am tasked with verifying it satisfies laplace's equation, determining the electric field, and describing the charge distribution on the plane. Homework Equations then The Attempt at a Solution As far as I...

I need some book on Electrostatics. I don't have knowledge in this field so I need something "beginner friendly", I mean it should cover this subject from very beginning. Thanks in advance.

Homework Statement Four equal point charges q = +22.4 μC sit at each corner of a square. What charge Q, in μC, must be placed in the center so all the charges are in equilibrium? Your answer must include the sign of the charge. Homework Equations F = q1*q2 * k / r^2 3. The Attempt at a...

If we have two negatively charged bodies , say A and B, and body A has more electrons on its surface than Body B , would the electrons of body A transfer to body B?

Homework Statement Three charged particles are placed at each of three corners of an equilateral triangle whose sides are of length 2.7 cm . Two of the particles have a negative charge: q1 = -6.0 nC and q2 = -12.0 nC. The remaining particle has a positive charge, q3= 8.0 nC . What is the net...

I was just wondering why the strength of the electric fields of insulating surface charges like sheets and shells aren't dependent on the distance from the charge according to Gauss's Law?

Why does the method of images work?

Six mercury drops of equal size given potential of +3v and two other drops are given -3v potential. If they coalesce what is final potential This question had been eating my brain i know solution if they are given same potential but what to do when they have different potential

Given a system of two charges (+7q and -q) some of the field lines will terminate at -q while others go on towards infinity. I've read that the portion of the field lines that terminate is given by (1/7), but I have no idea why that is. I am supposed to find the maxium angle of a field line...

Ok we know that the electric field(uniform or non uniform) is a conservative field. Imagine three horizontal electric field lines in '+X' direction separated by unequal distances let's say line 1 and 2 is separated by distance 'a' and line 2 and 3 is separted by some distance 'b' such that...

Homework Statement Spherical capacitor with two linear and uniform dielectrics with relative permitivitty Ɛr1 and Ɛr2 is connected to constant voltage U. When second dielectric is removed, intensity of electric field by inner electrode is reduced by 1/3, and electric field by outer electrode...

Homework Statement Hollow dielectric cylinder, with inner radius a, outer radius b, and height 2h is uniformly polarized by volume. Polarization vector is normal on the bases of a cylinder. Intensity of polarization vector is given, P. The surrounding area is vacuum. Calculate intensity of...

Homework Statement A conducting sphere of radius a is surrounded by a neutral conducting shell of radius b (b > a).Connections are provided as shown in diagram. Initially, the sphere has a charge Q. The switch S1 is opened and then closed. The switch S2 is then opened and closed. Finally, the...

Homework Statement Given a situation like this: Where the two blocks are perfectly conducting materials and are touching, will they separate? If they do separate, will they have the net charge values you calculate in the initial setup using Gauss's Law? There are no numbers, it's just...

Our teacher derived an expression for electric field due to thin sheet using gauss law which was sigma/2*epsilon naught which was independent of r but dies that mean the field will be same even if r is 10000km but field is also equal to kq/r^2

Hello, so this was a past assignment question that I attempted. I got the right answer but in an incorrect way (I guess my thinking was not based on the concept?) 1. Homework Statement Three point charges of charge Q = 10...

I originally posted the following question on physics.stackexchange, but no one was able to answer it. I did find this answer on PhysicsForums, but I was already aware of the oscillation of electrons in response to an external electric field. What is the physical cause behind a material having...

Hi... I want to know why charge density is higher at sharp points in a conductor? I have gone through the analogy of two spheres connected by a wire... But is there any other explanation which is not specific to spheres...?

1. Two small spheres with masses m1 and m2 hang on weightless, insulating threads of length L1 and L2. The two spheres carry charges of q1 and q2 (like charges) respectively. The spheres hang such that they are at the same level with one another. The threads are inclined at angle theta 1 and...

A negatively charged plastic rod will negatively charge a pith ball when in contact. My understanding is that the extra electrons transfer from the rod to the ball, thus giving the pith ball a negative charge. When an electrophorus is charged and the metal pan is put on top, it doesn't become...

Homework Statement Plate capacitor with distance between plates 'd=4mm' is fully filled with homogeneous linear dielectric. Capacitor is connected to the source of DC voltage, first stationary state is established, then the capacitor is separated from DC voltage source. After that, dielectric...

Homework Statement You have a new unknown material. You want to get a rough approximation as to the location of the unknown material on the electrostatic series. You only have two tools at your disposal; some wax and a charge detector. Design an experiment (procedure) that will help you...

Hey, my teacher gave us this scenario and I didn't really understand how he went about doing this. I was wondering if there was someone who could shed some light. Thanks! You have a new material in front of you titled Material Gamma. You want to get a very rough approximation as to the...

Why is the dipole moment directed from negative to positive ?

I'm studying for the physics GRE and am fairly poor with EM. 1. Homework Statement What is the work needed to assemble four point charges q into a regular tetrahedron of side length a? Homework Equations W = 1/2ΣqiV(ri) The Attempt at a Solution Assume that the origin is at one of the...

In electrostatics, why is it that identical spheres that are touched for a brief moment or connected by a conducting wire (wire not gaining any charge) should have an equal charge? Why is that they come in an equilibrium of charge? For example - If we take 2 identical spheres one bearing a...

Hi! I have trouble with solving this problem and would be really thankful for some help. :) 1. Homework Statement Inside a thin, spherical metal-shell with a radius of 50 cm, a smaller homogenous metal-sphere with a radius of 20 cm is placed concentrically. The smal sphere is grounded through...

Homework Statement This problem is taken from 'Introduction to Electrodynamics' by David Griffiths. (a) Twelve equal charges, ##q##, are situated at the corners of a regular 12-sided polygon (for instance, one on each numeral of a clock face). What is the net force on a test charge Q at the...

Homework Statement My Physics course does not give an in-depth overview of electrostatics at all (it is rather shallow, focusing on electronics and circuit analysis). However, I find that I really need to understand it fully to form the basis for magnetism and generation. So... I have a few...

At the moment we are working through problems in Griffiths' Electrodynamics textbook and it got me thinking... In magnetostatics we have the magnetic vector potential A and in the use of dielectrics problems we have the vector D. Why is it advantageous to use these vectors and not just stick to...

Can anyone please tell me where I am going wrong? I am getting the incorrect answer for the Word Done should be: WD = q(3x^2-6y) ... Apologies for not changing it into the format on here - but for my revision I have pretty much done that myself.

I recently studied Gauss' theorum according to which there is no electric field inside a closed conductor. But an isolated chage emits field lines in all possible directions. So why is it that there are no electric lines from the surface of the closed conductor inside it?

I heard that maximum electric potential for charged ring is at its circumference. Is there an expression to find the electric potential at any point on the circumference of a charged ring?

Homework Statement Consider an electron-proton pair and compare its electrostatic force with that of the gravitational force [G=6.67x10^11 Nm^2/kg^2]. Homework Equations F = k * |q1 * q2| / r^2 k = 1/4π∈ The Attempt at a Solution I calculated the force by using the charge of an electron...

Imagine an uncharged solid spherical conductor. Inside this spherical conductor, there is a cavity of a weird shape carved out of it. And somewhere inside this cavity, there is a charge +q (or rather, a charge distribution of total charge +q). The charge +q induces an opposite charge -q on the...

Imagine a surface charge ##\sigma##. The boundary condition on ##E## is ##E_{above}-E_{below}=\frac{\sigma}{\epsilon_0}\hat{n}##, where ##\hat{n}## points outwards perpendicularly to the surface. Because the field inside a conductor is zero, it requires that the field immediately outside is...