Electrostatics Definition and 684 Threads

Homework Statement The total electric flux from a cubical box 34.0 cm on a side is 1.29 x 103 N·m2/C. What charge is enclosed by the box? ----and---- Three charged particles are placed at the corners of an equilateral triangle of side d = 1.00 m (Fig. 16-53). The charges are Q1 = +4.0 µC, Q2...

Homework Statement Two small plastic balls hang from threads of negligible mass. Each ball has a mass of 0.14 g and a charge of magnitude q. The balls are attracted to each other and the threads attached to the balls make an angle of 20.0 degree. with the vertical. The balls are 2.05 cm apart...

Homework Statement Three positive particles of charges 11 μC are located at the corners of an equilateral triangle of side 15.0 cm. Calculate the magnitude and direction of the net force on each particle. Homework Equations Coulomb's Law The Attempt at a Solution I think, that this is easy...

A negative charge cloud distribute as a ellipsoid and a positive point charge situated at the centre of the ellipsoid.What should be the dipole moment of charge distribution.I mean, if the negative charge distribution is spherical and positive point charge at the centre then surely dipole moment...

Hi, could someone tell me why you get a shock from contact with a conductor when you are charged and not from an insulator. As I understand it, if you become charged by friction then you have an excess of charge. Let's say I have gained electrons from another material I have rubbed against. If I...

A point charge outside a hollow conducting sphere will produce no field in the hollow interior: the metal shields the interior. But a point charge inside the hollow interior will produce a field outside: the same metal ceases to act as a shield. Why is this? (In particular, aren’t “inside” and...

I am working on a problem of electrostatics, and I am having troubles in trying to figure out one part of it. 1. Homework Statement It consists of an inner solid cylinder of radius ##a## with a voltage ##V_A##, and an outer coaxial cylindrical shell of inner radius ##b## and outer radius ##c##...

Hi there, I'm trying to brush up on some of my E&M and am comparing treatments of Coulomb's Law in introductory calculus-based texts with higher level material. My understanding was that Coulomb's Law (and by extension, calculation of the electrostatic force on a charged particle using F = qE)...

Hello I need some advice about electrostatic levitation concept and am trying to make an experimental setup for that. Consider two parallel plates with the same sign charge and the bottom plate is fixed in place. Therefore there will be a repulsive force which pushes the upper plate...

In a circuit there are two forces that act on the charges to keep the current uniform through out, ##\vec{f}=\vec{E}+\vec{f_s}##, where ##\vec{E}## is the electrostatic field and ##\vec{f_s}## is the electric field produced by chemical reactions. Inside an ideal battery, ##\vec{E}## and...

Just wondering if anybody knows if it is possible to write a closed form solution for this problem, or how to tackle it. Image charges?

Homework Statement (see picture) I understand one approach to this homework problem. I don't understand why an alternative approach fails. Homework Equations V = E*d The Attempt at a Solution The correct answer is (d), zero. An acceptable approach: 1) Realize that V is the same at both...

Why do we need infinitesimally small charge in definition of electric field? Since the test charge cannot exert force on itself, F on test charge will not change whatever the value of test charge q is. So, F/q will be same for any value of test charge. Then why do we need this limit of...

Homework Statement Options for answers: positive, negative, neutral, cannot tell 1) a positive point charge is brought near the outside surface of a neutral conducting sphere and released. The initial position of the point charge is on the on the positive x-axis and the sphere is centered on...

Homework Statement Locate two charges q each and two charges –q each on the corners of a square, with like charges diagonally opposite on another. Show that there are two equipotential surfaces that are planes. In this way obtain, and sketch qualitatively, the field of a single point charge...

Homework Statement One of two nonconducting spherical shells of radius a carries a charge Q uniformly distributed over its surface, the other a charge -Q, also uniformly distributed. The spheres are brought together until they touch. What does the electric field look like, both outside and...

Do you know any economical quantitative electrostatics experiments for the university level? I'm asking for some experiments for undergraduates in the electrostatics context. We have a Van-de-Graaff generator in our fundamental physics lab but this kind of devices are useful for demonstration...

Consider the following configuration: a grounded plane (very thin and with an infinite surface) and a positive (not important) point charge above it. What does grounded really mean? Can't I assume that it is neutral and it has infinitely many positive and negative charges? Because of the...

First by "stationary" I mean "with respect to each other" so as to avoid introducing relativity problems. I'm wondering whether there's a way to prove or disprove that given N > 1 point charges q_1, q_2, ..., q_n, is there always a way of putting them in 3-dimensional space such that all of...

That is probably a badly worded question but I understand electrostatics and I want to send simple but efficient radio signals. If I switch on a strong charge in one place it'll effect a charge away from it depending on "Coulomb's law". How is this equation expanded to explain more efficient...

Homework Statement A sphere of linear dielectric material with permittivity ##\epsilon_1## and radius ##a## is surrounded by an infinite region of linear permittivity ##\epsilon_2##. In the spherical region, there is free charge embedded given by ##\rho_{free}=\beta r^2##, ##0<r<a##, where...

Homework Statement An oil drop is charged negatively. How much charge is on the drop if the Electric Field is 6,400 N/C at a distance of 1.2 m? Homework Equations E=k q/r^2 I don't know if I should be using that equation for this one. The Attempt at a Solution I tried to do E/(k x r^2) = q...

Homework Statement I am trying to calculate the dipole moment of a cylinder of volume charge density ##\rho_0## of radius ##R## and height ##H## with is center coinciding with the origin. My guess is that it should be 0 because of the symmetry but I am not able to show it. Below is my...

Homework Statement Find the energy required to assemble two uniform hollow spheres of charge q between radii a and b with a volume charge density roh-v. The shells are separated by a distance c. *description of picture* - two identical spherical shells with inner radius a and outer radius b...

Homework Statement A spherical conductor of radius ##a## carries a charge ##q## and also there is a jelly of constant charge density ##\rho## per unit volume extending from radius a out to radius ##b##. Find the electrostatic energy stored in the configuration. Homework Equations ##\oint...

Consider a commonly-used capacitor made from two circular parallel plates with a ceramic dielectric between them. The plates have 12.5 mm diameter and the whole thing is 3 mm thick with a capacitance of 10 nF. Neglecting the finite thickness and extent of the plates, what relative permittivity...

Homework Statement Find the energy stored in a solid sphere by integrating ##\frac{\epsilon_0}{2} \int E^2d^3r## given that ##E=k\frac{r^2}{4 \epsilon_0}## for ##0<r\le R## and ##E=k\frac{R^4}{4r^2 \epsilon_0}## for ##r>R## Homework Equations ##U=\frac{\epsilon_0}{2} \int E^2d^3r##The Attempt...

The problem I have is about a simple remark made in the book 'Berkeley Physics Course Volume 2, Electricity and Magnetism', chap. 3 figure 3.4 b. It says that if we have an infinite sheet of charge but with 'other charges' present elsewhere in the system, the only thing we can predict is that...

Apologies in advance if this question seems trivial, I seem to have missed something conceptually and would like some clarification. If an electric field from a point charge does work on another charge and thereby loses energy, where does the lost energy come from? It is my understanding that...

Homework Statement An #a*b*c box is given in x,y,z (so it's length #a along the x axis, etc.). Every face is kept at #V=0 except for the face at #x=a , which is kept at #V(a,y,z)=V_o*sin(pi*y/b)*sin(pi*z/c). We are to, "solve for all possible configurations of the box's potential" Homework...

Hey guys, I am working on a video game which is based on electrostatics. You play a charged sphere and you can change its charge to interact with other charged objects, sticking to walls and ceilings and orbiting around other charges etc. I am curious what you think of the concept, and which...

Homework Statement I have a hollow, grounded, conducting sphere of radius R, inside of which is a point charge q lying distance a from the center, such that a<R. The problem claims, "There are no other charges besides q and what is needed on the sphere to satisfy the boundary condition". I...

Two small eqlly chrged spheres ech of mass m, are suspnded frm same point by silk threads of length l. The distnce betwen sphres x<<l. Fnd dq/dt wth whch the charge leaks off each sphere.. If their approach velocity varies as v=a/root ovr x where a is a constnt. ***** My ques is; how can the...

Homework Statement Prove that the field is uniquely determined when the charge density ##\rho## is given and either ##V## or the normal derivative ##\partial V/\partial n## is specified on each boundary surface. Do not assume the boundaries are conductors, or that V is constant over any given...

the interior of a closed conductor can have no excess charges in the static situation ...and even if they have excess charge ...then these charge resides on the surface of the conductor...not inside it... can anyone explain to me...y a closed conductor behaves so? wht connection does it...

I am curious how legitimate a solution Separation of Variables tends to give. I've been working problems out of Griffith's book on Electromagnetism, and am often uneasy as to the way things are done. I have two specific issues. The first, is that in spherical it is often necessary to remove...

I recently learned about faraday's law about electromagnetic induction , where you move a piece of magnetic towards and away from a coil of conductor, what if we replaced the magnet with an electret ( electrostatic equivalent to permanent magnet) and we moved it towards and away from a grounded...

Two questions: 1.) Consider a hollow conductive sphere that's initially charged. These charges will distribute themselves in such a way that the condition: E-field(inside)= zero is satisfied. Now consider a hollow conductive sphere with a charged object inside The charges on the...

At what minimum distance can a particle 4α2, with kinetic energi Ec=4.77MeV, approach to a radium core 226Ra88. This is how I solved it: From energy conservation: ΔEc+ΔEp=0 Ec=[(Z1*Z2*e2)/(4*∏*ε)]*(1/r2-1/r1) r2=1/[1/r1+4*∏*ε*Ec/(Z1*Z2*e2)] (1) dr2/dr1=0 ⇔ r1→∞ (2) From...

Homework Statement Hello PF, I could use some help calculating the electric field of a static quadrupole with side lengths a. The four charges are each placed in the corners of a square. (See attached picture). Homework Equations We've been given these as a help...

Two small particles have electric charges of equal magnitude and opposite signs. The masses of the particles are m and 2m. Initially, the distance between the particles is d, and the velocities of the particles have equal magnitude v. However, the velocity of particle 2m is directed away from...

Homework Statement Two similar point charges q1 and q2 are placed at a distance r apart in the air. A dielectric slab of thickness t(<<r) having dielectric constant K is placed between the charges. Calculate the coulomb force of repulsion between the charges. Now assume that a slab of...

If I have a grounded conducting material, then I know that $\phi=0$ inside this material, no matter what the electric configuration in the surrounding will be. Now I have a conducting material that is not grounded, then there will be (as long as I am dealing with static problems) no electric...

An electron with speed 2.00×10^7m/s is traveling parallel to a uniform electric field of magnitude 1.16×10^4N/C . #1). How far will the electron travel before it stops? f=ma=Eq=-eE a=-eE/m I got a=-2.81x10^15 Then I used v(f)^2=v(i)^2+2a(x-x(i)) Solved for x... x=-(V(i))^2/2(a) x=.0712m #2)...

I'm having difficulty establishing whether it's possible to have an electrostatic charge that flows. Can current exist AND electrostatic charge exist in the same place? Given a length of coated wire, could current flow through the wire and electrostatic charge exist on the insulation? Could...

Homework Statement Two small particles have electric charges of equal magnitude and opposite signs. The masses of the particles are m and 2m. Initially, the distance between the particles is d, and the velocities of the particles have equal magnitude v. However, the velocity of particle 2m is...

Homework Statement We have a charged straight wire with radius ra = 0.2 cm and with charge ta = 3nanoC/m. Around the wire there are two hollow concentric cylinders, so that the wire is in their axis. Let the charge on the first cylinder be of radius rb = 3cm and its charge tb = -1.5nC/m and on...

Homework Statement An infinite dielectric sheet having charge density σ has a hole of radius R in it. An electron is released on the axis of the hole at a distance R√3 from the centre. What will be the velocity which it crosses the plane of sheet? (e = charge on electron and m = mass of...

Homework Statement A cone made of insulating material has a total charge Q spread uniformly over its sloping surface. Calculate the energy required to take a test charge q from infinity to apex A of cone. The slant length is L. Homework Equations The Attempt at a Solution...

Electrostatics -- 3rd plate inserted into parallel plate capacitor Homework Statement This question is from the book by I.S Grant and W.R Phillips on Electromagnetism. Two large parallel plates of area A and distance d apart are maintained at potentials 0 and V. A third similar plate...