Electrostatic Definition and 884 Threads

This is probably painfully obvious, but I keeping getting the impression that aqueous ions can be separated spatially via electrostatic force. For example, dissolve some sodium chloride in water, and then put the container in an electric field. Wouldn't the sodium ions migrate to the negative...

if we have a solid conducting sphere with charges around it, then the elctric field inside the sphere is zero otherwise the electrons of the sphere would not be in equilibrium as there would be a net force acting on it. however if its a hollow sphere then why does the electric field inside the...

Homework Statement An infinitely large layer of charge of uniform thickness t is placed normal to an existing uniform electric field. The charge on the sheet alters the electric field so that it still remains uniform on both sides of the sheet and assumes values E1 and E2 (E1 on the left...

Homework Statement Find the electrostatic force of interaction between two halves of a spherical conductor of radius R carrying a charge Q. This thread already exists- https://www.physicsforums.com/threads/electric-force-between-two-halves-of-a-sphere.317380/ but is closed. Homework Equations...

I saw an experiment the other day, where a van de graaf generator charges up this big smooth chrome sphere. There is a "wand" with a much smaller sphere nearby that's grounded, and periodically a spark can be heard and seen when the big sphere dischrages to the wand, which corresponds to...

ZapperZ submitted a new PF Insights post Energy Gained by Charge in an Electrostatic Field Continue reading the Original PF Insights Post.

I found a book which suggests that the reason why plastic bags are sometimes hard to open (which feels like they were glued) is electrostatic forces, but no matter how I look at this, I can't come up with any explanation. Is the book correct? I understand insulators and conductors, how charges...

Homework Statement 2 concentric conducting spherical shells, with radii a and 2a, have charge +Q and -Q respectively. The space between the shells is filled with a linear dielectric with permittivity ε(r) = (ε0*a)/(1.5*a - 0.5*r), which varies with distance r. a) Use Gauss's law to determine...

Homework Statement Let's take two spheres that are somewhat nearby. On one sphere, sphere A, there is Q units of charge. Now, we take some little bit of charge q off of sphere A, and put it on sphere B. What should the ratio q/Q be if we want the electrostatic force between the spheres to be a...

I understand that electrically charged objects such as a rubber balloon or even the human body can hold several thousands of volts. What's troubling me is that I know the current that results from an electrostatic discharge is not enough to cause serious damage or kill a human, yet if you touch...

A block of aluminium is charged by a van-Graff generator and isolated in space, the goal is to measure the amount of electric charge in this block or at least a part of it. What equipment should be used and how? Note: the purpose is to investigate how does the geometry of the block affect the...

Homework Statement A sphere of radius R carries an electric charge Q, uniformly distributed inside its volume. (a) Using the expression for the electric field given in the lectures, compute the electrostatic potential V (r) inside and outside the sphere. Homework Equations E[/B] = -∇V The...

A charge s moved in an electric field of a fixed charge distribution from point A to another point B SLOWLY.The work done by external agent in doing so is 100J.What is the change in potential energy?Now that is not my actual question.I want to ask what does "SLOWLY" indicate?I know to apply the...

Homework Statement Calculating electrostatic pressure. A spherical balloon with radius 1.0 m is made of aluminum-coated Mylar. How many electrons must be deposited on the aluminum layer such that the resulting electric pressure is equal to one atmosphere? Homework EquationsThe Attempt at a...

I am learning in Electrostatics that the work done to construct a charge configuration is ∑qV and when we assume that charge is not discrete but continuous we get the work done to be ∫E.Edv and hence we say that the energy stored in electrostatic field is ∫E.Edv. when applying this formula to...

Homework Statement Consider potential field V(ρ, φ, z) = V_0/ρ in free space and cylindrical coordinates. Calculate electrostatic potential energy stored in half cylindrical shell defined by a≤ρ≤b, 0≤φ≤π and 0≤z≤h. Homework Equations W_E=½∫∫∫ρ_vVdV The Attempt at a Solution I have no idea...

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 Consider the figure below, we need to find the charge on Q_0, both charges Q are negative. It is given that the net charge on Q_A is zero. The figure of the problem is attached. The Attempt at a Solution I understand how to get the solution except for one part. I'm just...

We have a question about finding the electrostatic force acting on a particle from another particle. They are colinear since there is only the 2 particles, but not along an axis. My question is, why does finding the force in the x direction and finding the force in the why direction, then...

Homework Statement How do we define an electrostatic potential? My teacher tried to explain it through teaching us gravitational potentials, and I have presented what I came up with under '3.The attempt at a solution'. Please see below and thanks in advance for any help in clarifying whether my...

Homework Statement As an electron moved through a region of space, its speed changed from an initial velocity of vi=8114.3 km/s to the final velocity vf=2233.7 km/s. The electric force was the only force acting on the electron. Across what potential difference did the electron travel...

Someone told me that dust can not be charged becuase it does not have chemical polarity. Is that right? Should materials have chemical polarity to be charged?

Two charges, q1=-9.4 μC and q2=1.2 nC with masses m1=13.4 gram and m2=2.7 gram were located 8.5 cm from each other. Charge q1 is held in place. We wish to push the 2nd charge q2 as far from the 1st charge as possible. With what initial velocity should charge q2 be pushed to send it all the...

Figure (a) shows a narrow charged solid cylinder that is coaxial with a larger charged cylindrical shell. Both are nonconducting and thin and have uniform surface charge densities on their outer surfaces. Figure (b) gives the radial component E of the electric field versus radial distance r from...

Homework Statement Find the magnitude and direction of net electric field at the center of the square array of charges. Find E_x and E_y The square array of charges http://postimg.org/image/4gf94ymmf/ The Attempt at a Solution [/B] My attempt at drawing in the force vectors...

Homework Statement Given a spherical shell of radius R and the surface charge density ( being the angle from the top of the sphere and being a constant) find the electric potential and the electric field inside and outside the sphere. Check that both the potential is continuous inside and...

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...

Homework Statement Im having trouble posting the image sorry. But there's three charges. q1=30uC q2=? q3=60uC q1 to q2 distance equals 30cm q2 to q3 distance equals 60cm q1 is left of q2 and q3 is to the right of q2. Homework Equations F=k*qq/r^2 The Attempt at a Solution [/B] Given where q2...

Homework Statement Point charge Q = 4.26 μC is fixed at the origin. Now, point charge q = 4.88 μC is carefully placed directly above it (along the y-axis), and it floats at (0,9.51 cm). Find the mass of q, in kg. Assume: g = 9.803 m/s^2. Homework Equations F=kq1q2/r^2 G=mg probably The...

I'm confused as to how the Born-Landé equation can be extrapolated to find the electrostatic potential for an ionic lattice without halving it, as each interaction is otherwise counted twice. As I understand it, and according to Wikipedia, the electric potential energy in a charge configuration...

Homework Statement Find potential of a uniformly charged rod of length 2a Homework Equations -Superposition The Attempt at a Solution dV=\frac{kλdx}{r}, r=x V=λk\int\limits_{-a}^a \frac{1}{x}\mathrm dx=0 Potential at point B is zero. Is this correct?

Homework Statement Wire conductor of length l consists of two part with equal length in series, and of specific conductivity σ1 and σ2. When conductor is connected to constant voltage U, what are electric fields in parts of this conductor? Homework Equations J=σE The Attempt at a Solution...

Homework Statement Coaxial cable has double layered dielectric. a=2mm, b=4mm, c=8mm, εr1=3, εr2=4.5, Uab=1000V 1. Calculate capacitance per unit length of a cable. 2. Calculate inner and outer charge densities of a cable. 2. Homework Equations Gauss law C'=Q'/U σ = nD σp = nP 3. The Attempt...

Homework Statement Two cylindrical conductors, of distance between them d and radius a (a<<d), have dielectric layer of relative permitivitty εr and thickness a. Calculate capacitance per unit length of this system. Homework Equations Capacitance per unit length, C'=Q'/U Gauss law, cylindrical...

Hello everyone, I am currently learning how to use a simulation C++ library (for those wondering, it is the deal.II library) by simulating a "simple" problem where I have a charged parallel plate in free space and I am solving for the electrostatic potential around the plates. For those that...

Homework Statement A typical inflated balloon has a mass of 4g. Two balloons are rubbed against wool, touched together and then suspended by someone holding the thread at its centre. It is found that the ballooons rest so that trheir centres are 42cm apart and that the thread encloses an angle...

what are the generalised and more quicker ways of finding Force that multiple charges (4 charges along the y-axis and x-axis at most) exert on the origin charge Q. i have used a cartesian plane to try solve for the vectors but seem to not get to the right answer.

Hello. I was trying to understand the mathematics underlying Faraday cages. After hours of research on the web, It turns out that there are very few mathematical analysis related to Faraday cages, even in the electrostatic case, and those that I read do not satisfy me. So, I tried to solve the...

Homework Statement Find potential and charge per unit length of every cylindrical hollow shell if the outer shell is grounded. The length is considered to be infinite. Homework Equations V=∫Edl The Attempt at a Solution I am not sure how to derive potentials for first two conductors...

Homework Statement I'm right now trying to solve a question concerning the direction of an electron in an electric field. There is the picture I added given and you know that there is a homogeneous electric field. The blue line represents the movement of an electron (there is no movements up...

If you rub two electrically neutral pieces of insulation together, one piece becomes charged and the other piece becomes oppositely charged. Does this transfer of electron depend merely on the electron affinities of the two pieces, or does the conductivity of the two insulations play a part? I...

Homework Statement two proton beams going in same direction repel each other whereas two wires carrying currents in same direction attract each other Homework EquationsThe Attempt at a Solution two proton going in same direction then it makes two current going in same direction. And current...

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...

http://www.colorado.edu/physics/phys3320/phys3320_sp12/AJPPapers/AJP_E&MPapers_030612/Griffiths_ConductingNeedle.pdf I was reading this paper, and was confused by a result in section 2-A. (Heck they even mention they weren't expecting it themselves). The purpose of the paper is to find the...

Homework Statement I am working on a problem that states the following: Imagine an infinite straight wire carrying a current I and uniformly charged to a negative electrostatic potential Φ I know here that the current I will set up a magnetic field around the wire that abides to the right...

My question was was that though you don't have any charge on the inner surface of a metallic cavity but still there's a potential. Can't that potential electrocute someone?

Homework Statement "An object is moving in a straight line from a positively charged area (A) to a negatively charged area (B). Explain how the electrical force and electrostatic potential energy experienced by the object will vary when it is neutral (has no charge)." Homework Equations N/A as...

After calculating the force upon an electron and a force upon a proton in the atom of hydrogen, my result was a force of ≈8.2x10-8 Newtons acting upon the electron and proton each. If found this by using the formula Fe = (ke q1q2)/r2 Taking this number, I then applied it in the formula F = ma...

What I studied was that the force on one charge due to another equal charge in the system of two charges was, (say) F; whereas the force on the other charge due to the first charge was found out to be -F. Hence they add up to be zero. So can I say that the two equal charges are in electrostatic...

1. The problem statement, all variables a nd given/known data A rectangular trough extends infinitely along the z direction, and has a cross section as shown in the figure. All the faces are grounded, except for the top one, which is held at a potential V(x) = V_0 sin(7pix/b). Find the...