Charged Definition and 1000 Threads

I am wondering about why the electric field in a hollow sphere with charges on its surface would be zero. I have thought about the gaussian law argument for it. It only guarantees that the net number of electric field lines that pass the encloved surface are zero. But it says nothing about...

Q: "A graduate student tells you that he has observed a Schottky defect in a sample of pure aluminium. Explain why it may take a long time for this graduate student to get his Ph.D" A: "Pure aluminium has no negatively charged particles, so a Schottky effect can not occur." So I know a...

A rather simple question. A confinement of positively charged ions , a tube from the confinement and in the end of the tube a metal plate at a negative potential , if the charged ions are let to run towards the negative metal plate (which they would normally do) the plate would loose it's...

Homework Statement Hi, I am having problems trying to solve an electrostatics question. Basically there are two circular sectors of radius R and with angle 2β. Both of these sectors have their vertices at the same point in the xy plane (ie at the origin) but have a separation d in the z...

Homework Statement A hollow spherical conducting shell is suspended in air by an insulating string, so that the sphere is electrically isolated. The total charge on the conductor is -6 μC. If an additional point charge of +2μC is placed in the hollow region inside the shell, what is the total...

Say you have a charged, parallel plate capacitor, isolated from any external circuit. If you were then to gradually separate the two plates (or thicken the dielectric) what would happen to the charge on the two plates ?

Two charged objects of charge q. Coulomb's law states that the force on one sphere by the field of the other is: F = qE But each sphere experiences that, correct? So the tension for the string would be 2F. Is that correct?

Hello community, I'm new here. I'm using FORTRAN to model the motion of electrons and ions when accelerated under a high voltage potential. I'm using a fluid approximation and MHD-like equations (conservation of mass, energy, momentum) and a finite volumes numerical method to solve the...

Hello, I would like to share a cool experiment... but not yet experimented for me. Suppose you have a ball of metal between two plates. The upper plate is charged - and the lower plate is charged + There is constant potential between the plates. When the ball touches the lower plate, it...

Hi, just reviewing some of my physics material, and realized I had a question that has never been answered for me. I know that charged particles, traveling parallel to a magnetic field, feel no force either forwards or backwards, but feel a force perpendicular that causes them to spiral...

hi every one on an exercise on book we ask us to find the electrical field for a uniformly charged ring where we going to find : E=kqz/(z2+R2)3/2 then we have to derivate it wth respect to z and we find : dE/dz=kq*(R2+2z2)/(z2+R2)5/2 so my question is how do we get this derivation ?

Consider that the bar has a linear density λ and is in the x axis. Also consider that V=0 in infinite. Determine the potential in point P. I can calculate it, but I don't understand how the bounds of the integral are supposed to be determined: dq =\lambda dx'\\ r = x + x'\\dV =...

Homework Statement I'm almost embarrassed to post this, but insofar none of my searches online have yielded any results. My question is simply, given a parallel plate capacitor (for the purpose of simplicity let's assume that there are no edge effects) whose constituent plates have charge +aQ...

Anyone know if there are any graphical simulations online for the field of a charged harmonic oscillator, or better yet maybe some kind of paper on it?

I have been looking at mass spectrometers, in particular the interactions between the Bf ind of a charged particle in motion in a static Bf of the spectrometer. Figure 1 and 2 shown below are a basic 2 dimensional slice of the problem from the top (fig 1) and from the inside of the radius...

If I have a charged object in contact with normal air (but nothing else) and insulated, does it lose charge over time? Does the answer depend on the object being an conductor or an insulator itself?

Homework Statement A spring with an unstretched length of 20 cm and a force constant of 100 N/m is attached to a 2-kg mass with a charge of 3.0 C. The mass is swung in a circle in a zero gravity environment, so that the spring is perfectly horizontal and is parallel to the radius of the...

Homework Statement A long hollow nonconducting cylinder (radius R= 0.060 m, length L= 0.70 m) carries a uniform charge per unit area of σ= 4.0 C/m^2 on its surface. Beginning from rest, an externally applied torque causes the cylinder to rotate at constant acceleration α= 40 rad/s^2 about the...

I have read that if we have an isolated positively charged conductor, we can increase itself capacitance by bringing an identical conductor close to it and then earthing it, so, that the second conductor develops a negative charge and thereby helps in reducing the net electric potential on the...

Homework Statement Suppose you have a capacitor with capacitance C charged to voltage V and a second capacitor with capacitance C charged to voltage 2V. The two capacitors are connected in parallel. What will be the voltage across the two capacitors after being connected in parallel?Homework...

Homework Statement Find the electric field at a point on the x-axis due to a uniformly charged, hollow cylinder. The x-axis is parallel to the cylinder and goes through it's centre. One end of the cylinder is located at the origin. Homework Equations R = radius of cylinder Q = charge on...

A spherical conducting shell with charge total q surrounds a charge –2q at the center of the shell. The charges on the inner and outer surfaces of the shell are respectively I know that if the conducting sphere has no charge the inner and outer charges would be +2q, and -2q respectively but...

Problem (a) Derive and expression (using cylindrical coordinates) for the drift velocity of a particle of mass m and charge q in a uniform vertical magnetic field B\hat{z} when the particle is located at a perpindicular distance p from a long, straight vertical wire carrying a line charge...

Homework Statement Each of the nuclei below are accelerated from rest through the same potential difference.Which one completes the acceleration with the lowest speed? 1H1 4He2 7Li3 9Be4 Homework Equations F=ma=QE The Attempt at a Solution v∝a∝Q/m so for lowest v Q/m lowest is 1 so...

Where can I find a picture of the magnetic field lines produced by a charged particle moving near the speed of light? Is there a formula for the strength of B and direction of field lines as v --> c? Does this equation reduce to Ampere's right hand rule for a moving charge's ability to create...

if we assume a charge particle enters in a uniform magnetic field with velocity V w.r.t inertial frame as shown fig. then according to the situation shown there will be force acting on particle due to magnetic field (neglecting B field induced due to charged particle itself). But now if we...

Homework Statement Show for a solid spherical ball of mass m rotating about an axis through its center with a charge q uniformly distributed on the surface of the ball that the magnetic moment μ is related to the angular momentum L by the relation μ=(5q/6mc)L Homework Equations μ=IA/c...

Homework Statement I am given a circuit in which my homework is asking my to find the time constants of this circuit: The problem wants the time constants and then wants to find the voltage response when the circuit is in the position connecting the 2k ohm resistor. the capacitors...

Homework Statement One capacitor is charged until its stored energy is 4.0 J, the charging battery then being removed. A second uncharged capacitor is then connected to it in parallel. (a) If the charge distributes equally, what is now the total energy stored in the electric fields?(b) Where...

We can easily find from gauss's theorem(or otherwise) the field inside and outside a uniformly charged spherical shell.But i was wondering what would be the field on the surface of the shell.

Homework Statement Find the electric field along the y-axis of a charged semicircle (with the center of the circle in the origin) with radius R, with a uniform charge distribution $$ \lambda$$ ...

Generally the concept of dipole moment is used in neutral system, ie the total positive charge equals to the total negtive charge. Could the concept and also the calculation be used in charged system? For example, NaOH, (Na+)(O-2)(H+), we can calculate its dipole moment. Could I calculate...

So, these two obviously violent individuals could be released in 2 years or less? I keep reading that serial killers start by torturing and killing animals when they are children. I wouldn't be surprised if these two are also into that, but have also decided to move on to humans. I'd like...

Homework Statement For a sheet of infinitesimal area, find the electric field 9 mm from the surface if the charge density is 5 μC/mm^2. Homework Equations E=σ/2ε0 The Attempt at a Solution E=(5x10^-6 C/m^2)/(2*8.85x10^-12) = 2.8 x10^5N/C I know the correct answer is about...

Homework Statement See image Homework Equations KQ/r^2 The Attempt at a Solution I have seen several different ways of working this problem, but they have all failed on me. I tried this using the equation above from my book E = (8.99x10^9)(1036 C)/(4x10^-6m) E= 2.328x10^18 N/C I also...

Homework Statement The question asks to find the potential due to a uniformly charged sphere at r<R where R is the radius. Homework Equations Va-Vb= ∫ E dr from a → b The Attempt at a Solution My attempt was like this Va is to be a the point of interest r.. Vb to be R... We...

Two charged particles of equal magnitude are located along the y-axis equal distances above and below the x-axis. Plot a graph of the electric potential at points along the x-axis over the interval -3a<x<3a. You should plot the potential in units of (KeQ)/a Let the charge of the particle...

the calculation of the E field a distance z above a spherical surface of charge gives rise to this integral which can be done by partial fractions...I don't see this integral in Stewart's table did I not input correctly in Mathematica? Integrate [(z-R*u)/(R^2+z^2-2*z*R*u)^(3/2),{u,-1,1}]...

Hi! What is the limit to how much you can electrically charge two plates? I want to create the maximum possible force between the two plates per kilogram of plate. Say that the plates are separated by a good vacuum, because that is the best insulator, right? The plates are also surrounded...

My book gives the electric potential of a uniformly charged sphere as \frac{1}{4\pi \epsilon_0}\frac{Qr^2}{r_0^3}. I can't derive this forumula. What I get is \frac{1}{8\pi \epsilon_0}\frac{Qr^2}{r_0^3}. I can guess how the book did it which is by taking the equation for voltage of a single...

Hi, Is it correctly understood that all charged molecules are polar (if they have a charge at some point, they must also have a unequal distribution of positivity and negativity) but polar molecules can be charged or uncharged ( they have Δelectronegativity)

Homework Statement 1. 2. Homework Equations ∫E.dA = Qenc/\epsilon_{o} \lambda=Q/L \rho=Q/V V= q/4πε_{o}r The Attempt at a Solution these types of problems i suck at, i don't know how to do these at all independently, and is there any difference in question 2 if there is an insulator or...

I'm currently on the chapter on capacitors in my physics book. I'm starting to get the concept, but everything still isn't crystal clear. I get that you can store charges in two plates, one containing a charge of Q, and the other a charge of -Q. But, would it not also work if the charges where...

Hello, I am reading through the problem given in this link: http://physicstasks.eu/uloha.php?uloha=300 There is one sentence I am particularly unsure of, "Charged ball's potential is in direct proportion to the charge of the ball and in reciprocal proportion to the ball's radius." Why is this...

Homework Statement Consider an infinite charged line along the z-axis, with linear charge density . The charge moves uniformly with velocity v in the positive z direction. 1. Give an expression for the electric and magnetic field. 2. Give an expression for the energy flux density (or energy...

Homework Statement A metal sphere of radius 10 cm carries a charge of +2μC uniformly distributed over its surface. What is the magnitude of the electric field due to this sphere at a point 5.0 cm outside the sphere's surface? 8.0 x 109 N/C 4.2 x 106 N/C 8.0 x 107 N/C 4.0 x 109 N/C 4.0 x...

Hello, I am confused as to what happens when a capacitor is charged by a battery, disconnected, and then connected to a second uncharged capacitor. Is the situation different for whether the two capacitors are connected to each other in series or parallel? If in series, shouldn't the charges...

Lets say we have an infinite charged wire with a line charge \lambda on it. Now when I move with respect to this wire the E field will increase do to length contraction. And there will also be a B field that we could calculate with ampere's law. But the increased E would make it seem...

Homework Statement In the section on the discontinuity of the electric field (Griffiths introduction to electrodynamics) there is the following. "Where there is no surface charge, the perpendicular component of the electric field (to the surface) is continuous, as for instance at the...

Hi everyone, i have been looking at this problem for a few days now and i am pretty stuck, ill explain why first the problem : a charge Q is distributed over a ring section of radius r, between angles 90 and 180. find the V and E at the origin. Now the problem I am having ais everything...