Electrostatics Definition and 684 Threads

The problem was to give the charge distribution of a uniformly charged disk of radius R centered at the origin and perpendicular to the z-axis. The professor explained us how to do so (though many parts were unclear to me and I couldn't copy everything that was on the blackboard because we were...

1. For a coaxial cable, calculate E, D, H, and B everywhere assuming a uniform current I in both conductors and uniform charge per unit length on both conductors. Then find: inductance and capacitance per unit length, leakage resistance across the dielectric per unit length, and conductor...

Homework Statement Two point charges are separated by 5 cm. The attractive force between them is 16 N. If the two charges attracting each other have equal magnitude, what is the magnitude of each charge? Enter a number. Coulombs Homework Equations Force =k*(q1*q2/d^2) The...

Homework Statement A spherical shell with potential: V(r=R)=V_0cos\theta (a) Please solve the potential inside and outside the shell. (b) if there is a point charge at the center and the potential of the shell keeps the same, solve the potential inside and outside. Homework Equations...

1. Two point charges q and 4q are at x=0 and x=L, respectively, and free to move. A third charge is placed so that the entire three-charge system is in static equilibrium. Two point charges q and 4q are at x=0 and x=L, respectively, and free to move. A third charge is placed so that the entire...

1. q_2 is in static equilibrium. What is q_1? There's a particle with a charge of -3.0nC between q_1 and q_2, 10cm from each. 2. F = |q1||q2|*K/(r^2) 3. I know the answer is 12 nC but I don't see how to get it. I figured you had to approach the problem using the above equation...

anyone can help me out? I've tried but my answer and answer key are differnet! Homework Statement three point charges lie on a straight line. find the resultant force exerted on (a) the -2\muC charge, (b) the 5 \muC charge 1 (5\muC) 2(-2\muC) 3(3 \muC) distance...

Homework Statement There is a charged wire aligned/centered along the Y 2L in length. A test charge is placed D distance from the wire on the X axis. The wire has a total charge of Q. calculate the integral to figure out how much force the test charge experiences. a semi decent pic of the...

1. b]1. Homework Statement Two large metal plates are held tightly together. Two equal and opposite point charges are placed one each on either side of the plates, and equidistant from them. The line joining the two charges is perpendicular to the plane pf the plates. What will happen when...

Homework Statement A point charge q is held a distance d > a below the centre of a large spherical conductor of radius a. Show that, if the spherical conductor is earthed, the potential outside the sphere may be found by placing an image charge at a distance c=a2/d from the centre of the...

Homework Statement Three positive particles of charges +7.0 uC are located at the corners of an equilateral triangle of side 20 cm. Calculate the magnitude and direction of the net force on each particle. Answer: 19.0 N [AWAY FROM THE CENTRE] Homework Equations F = (kQ1Q2)/(r^2)...

Homework Statement 1. A thin rod bent in the shape of a semicircle of radius 20 cm is uniformly charged along its length with a total charge of 8.0 microC. What is the electric field at the center of the semicircle? a. 7.3 x 10^4 N/C b. 8.4 x 10^4 c. 5.7 x 10^4 d. 3.9 x 10^4 e. None...

1. In hydrogen atom the distance between electron(e=1.6*10^-19 C)(Mass of electron=9.1*10^-31 kg) & proton(Mass Of proton=1.7*10^23 C) is 5.3*10^-11 m. 2. Calculate the electrical and gravitational forces between 2 particles 3. Can't do the problem... Please help!

Homework Statement A force of 4.30\cdot10^{-2} Newtons is needed to move a charge of 56 microCoulombs a distance of 20 cm in the direction of a uniform electric field. What is the potentioal difference that will provide this force Homework Equations Im trying to find one that would work The...

Homework Statement Find the electric field a distance z above the center of a spherical surface of radius R, which carries a uniform charge density "sigma" Treat the case z<R(inside) as well z>R (outside). express your answers in terms of the total charge q on the sphere.[hint:use the law of...

Homework Statement a) Consider a conducting sphere of radius R whose surface is maintained at a potential \Phi(R)=\Phi_0cos\theta. Assuming that there are no charges present (inside or outside), what is the potential inside and outside the sphere? b) Consider a cylindrical conducting can of...

Hi all I'm new to this forum, and this is my first post. I have a question related to a claim by Ralph Rene, and his 'disproof' of Coulomb's law. Rene was a prominent moon hoax believer and called himself the 'Last Sceptic of Science'. Amongst his claims were his reduction of relativity to...

Homework Statement How would you solve the one-dimensional Poisson's equation: $\nabla ^2 \phi = \frac{\rho}{\epsilon_0}$ Using Fourier Transforms? $\phi (x) = \int ^{+\infty}_{-\infty} G(k) e^{-i k x} dk$ $G(k) = \int^{+\infty}_{-\infty} \phi (x) dx$ I've been trying to understand Fourier...

Homework Statement Two electrical dipoles with dipole moments \vec{p}_0=p_0\hat{y} and \vec{p}_1=p_1\hat{y} are located in the xy-plane. \vec{p}_0 i located at the origin and \vec{p}_1 is initially in (x,y)=(a,0). What work is required to move \vec{p}_1 (with unhanged directon) to the point...

Electrostatics: spherical shell [SOLVED] Homework Statement A point charge Q_1 is located in the centre of a spherical conducting shell with inner radius a and outer radius b. The shell has total charge Q_2. Determine the electrostatic field \vec{E} and the potential \phi everywhere in...

Homework Statement Consider two infinite conducting plates of some thickness with charge 2q and -q. The system is in equilibrium, which means there's no charged particles in motion. Find the charge distribution on the surfaces of each plate. (designated as q1 q2 q3 and q4) Homework...

There's no problem as such here, just a bit of confusion I'm having regarding finding the electric field. On the following page, second example, is the equation for finding the electric field above a charged disc http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/elelin.html#c2". I understand...

Homework Statement A spherical shell of radius R with uniform charge Q is expanded to a radius H.find the work done by electric forces during the shell expansion given answer is 1/(8pi epsilon) *Q^2(1/R-1/H) my attempt work=-change in P E =Q(V1-V2) =1/(4pi epsilon)...

Homework Statement Describe how a metal sphere on an insulating stand is charged if a positively-charged rod were to touch the sphere. (This is a 5 mark problem, so at least 5 major points should be included in the answer. I am not sure whether I have fully answered the problem.) Homework...

I already know what the answer to this problem should be, however I do not understand why that is the case. Homework Statement The negative charge (= -1 micro Coulombs) in the figure below goes from y = -5 to y = 5 and is made to follow the dashed line in the vicinity of two equal positive...

So I have to do a lab, where I rank common household materials based on electronegativity. I am told to acquire two plastic combs and two pieces of string with which to hang them freely off a table. Besides that, I am to acquire common household materials such as rubber, wool, cotton, glass...

Homework Statement Two identical conducting spheres, fixed in place, attract each other with an electrostatic force of 0.0898 N when their center-to-center separation is 39.6 cm. The spheres are then connected by a thin conducting wire. When the wire is removed, the spheres repel each other...

Friends, Can anyone solve this mcq on electrostatics with proper explanation If a net charge is given to a solid insulating sphere then: a. it must be distributed uniformly in it's volume b. it may be distributed uniformly in it's volume c. must be distributed uniformly...

Friends, I am not being able to solve the following problem i would be grateful if anyone could help me out. here is the problem: eight equal point charges each of charge q and mass m are placed at eight corners of a cube of side a. if keeping all other charges fixed a...

Homework Statement three small identical balls have charges -3C,8C and 4C respectively. they are brought in contact and separated. calculate charge on each ball? Homework Equations q=(q1+q2+q3)/3 The Attempt at a Solution what is the need for dividing by 3. why not simply add the...

In Feynman's lecture on the principle of least action, he show that you can describe electrostatics by saying that a certain integral is a minimum or maximum. He states the integral, and goes on to show how it can be used to approximate the capacitance of a coaxial line. I've been able to...

Homework Statement Use Gauss' theorem (and the fact that the line integral of the electric field around a closed loop is zero, if necessary) to prove that a closed, hollow conductor shields its interior from fields due to charges outside. (This is 1.1b in Jackson, and it's not really homework...

Imagine that you have N points scattered in the plane. Each point is charged and contributes to the total potential the same Coulomb potential proportional to 1/r. Now consider some equipotential line of the total electrostatic potential. Is there an analytical expression for the surface...

Two parallel uniform charged circular conducting metal disks contains a charge of +Q and -Q on the inner surfaces, and little amounts of charge +q and -q on the outer surfaces. The detail is shown in the diagram. Each plate has a radius R and thickness t. The separation of the plates is d...

Hello, I am trying to use the electrostatics module in COMSOL ( I just started a few days ago). The other day, I was able to create a 2D box, apply a charge at one side (via boundary condition), and ground the other sides. I solved, and got a neat output, that I suspect is correct. Then...

Hi, I have an exam coming up soon. But I thought I would clear my doubts ahead of time. 1. A fixed conducting ball has charge q1= 3X10^-6C. An identical ball with charge q2 is held at a distance x away from q1. The two balls attract each other with a force of 13.5N. The balls are then...

I have asked this question before in another section of the forum but I still don’t have an answer so I thought I would try here. Ok…here goes.. In three dimensions, Poissons equation can be used to model an electrostatic problem in which there is a single point charge at the origin. The...

Homework Statement Consider a simple 3-body problem in one dimension. One body (the projectile) has mass m. The second body (the target) is made up of two "atoms" each of mass M/2 (total mass = M). Assume an internal spring holds the two atoms together. If the projectile is sent toward the...

Homework Statement Hello, 4 charges of equal magnitude are placed on the corners of a square of length a. The two charges at the top of the square are negative, while the two charges at the bottom of the square are positive. what is the magnitude of electric field at the centre of the...

Homework Statement Suppose a conducting spherical shell carries a charge of 3.00 nC and that a charge of -2 nC is at the center of the sphere. If the distance from the center to the inner shell is 2.00 m, and the distance from the center to the outer shell is 2.40 m, find the electric field...

Part C The answer is zero. But I am not sure what I am missing. I am using a Pentagon to do the analysis (I don't feel like drawing a 13-sided object). It seems like I need to know a little more about the geometry of a Pentagon. How is the center of an odd-number-of-sides polygon...

Homework Statement a) Why do pie pans fly off the Van de Graff Generator when turned on? b) When foam peanut are placed inside a pie pan with the Generator turned on, what causes the foam peanuts to fly out? c) Why does a person's hair stand up when they touch the generator...

Homework Statement Past exam question: Briefly explain the roles of symmetry, uniqueness and superposition in solving electrostatics problems. Homework Equations N/A The Attempt at a Solution I know the definition of these words and could cobble together an answer from that - but...

State Gauss' Law A spherical volume carries a uniform charge density \rho_0. A particle of mass m and charge -q is placed inside the sphere at radial distance r. (This additional charge does not distort the field arising from the \rho_0 charge density.) Show that the particle oscillates...

Homework Statement For a given configuration i found the scalar potential \phi(r)-->(as you can see its a function only of r) My question is about calculating the energy of the system. Homework Equations W=-\dfrac{\varepsilon_0}{2}\int |\nabla \phi|^2 d^{3}x =\dfrac{1}{2}\int...

A point charge Q is placed at the centre of a cube. What is the electric flux through each face of the cube. ok so the answer is to say that since the cube is a closed surface, Gauss' Law tells us that the total flux through the cube is \frac{Q}{\epsilon_0} and then from symmetry 1/6 of that...

Homework Statement An electron is released from rest 2.0 cm from an infinite charged plane. It accelerates toward the plane and collides with a speed of 1.0x10^7m/s. What is the surface charge density of the plane?The answer is 2.52×10−7 C/m^2 ! Homework Equations v=d/t, d=0.5at^2...

There is a cunducting hollow sphere. We know if we charge it all the charges will stay at the outer surface. But if we drill a hole of radius r(say) then what fraction of the charge will remain inside and outside surface I think it is logical to think that less charge will stay in the...

Homework Statement A grounded spherical shell has inner radius of 1m. and outer radius of 2m. Q1=1 Coul. is located at x=0.5m and Q2=-2 Coul. is located at x=4m, respectively. Homework Equations Find the charge system to find the potential outside the shell. Find the charge system to find...

given a dipole as in the diagram (http://picasaweb.google.com/devanlevin/DropBox?authkey=Gv1sRgCL_4l4PpvP_YsQE#5311991019489958690 ) with charges of +q and -q placed a distance of "d" from one another. a) what is the electric field at point z, on a line 90 degrees to the middle of the dipole...