Point charge Definition and 345 Threads

Homework Statement Consider the electric field created by a very long charged line of negative linear charge density -2.50 nC/m. A small positive point charge of 8 mC moves from a distance of 9 cm to a distance of 17 cm. How much work is done by the electric field? Hint: The...

Hi, I'm writing a small simulator where two objects apply force on each other inversely proportional to square of distance between them. ( like gravty ) in terms of gravity, I think this is the only force that I have to take into consideration. but I'm confused about electrical and magnetic...

Homework Statement There is a negative point charge between 2 oppositely charged plates. Positive at top and negative at bottom. The electric field runs downwards from pos to neg. In which direction is the electric field of the point charge. Homework Equations The Attempt at a...

Homework Statement A 4.9-µC point charge is located at x = 1.1 m, y = 3.1 m, and a -3.9-µC point charge is located at x = 2.1 m, y = -1.9 m. (a) Find the magnitude(inkN/C) and direction(in degrees) of the electric field at x = -3.2 m, y = 0.9 m. (b) Find the magnitude(in N) and...

Homework Statement Show that B for a point charge is equal to Homework Equations I'm not all that sure. I read that maxwell's equations can be used to derive this, so I'd imagine that it's The Attempt at a Solution If it were that, then, if i have a point charge moving...

While reading through the Feynman Lectures on Physics (volume 1, number 28) I have come across the formula for the electric field for a moving point charge - it's the equation labelled (1) on this page: http://maxwellsociety.net/PhysicsCorner/InteractingParticles/AcceleratingCharges.html...

Homework Statement Show that with d spatial dimensions the potential \phi due to a point charge q is given by \phi (r) = \frac{\Gamma(\frac{d}{2}-1)}{4\pi^{d/2}}\frac{q}{r^{d-2}} Homework Equations The Attempt at a Solution The electric field strength is known to be: E(r) =...

Homework Statement It is found that Poyntings vector gives P = ExH = (mu0q2a2sin2(theta)/6pi2cr2)r This apparently leads to Total Power = (mu0q2a2/6pi2c)\int(sin2(theta)/r2)(2pir2sin(theta)d\theta) What I am unsure of is where the (2pir2sin(theta)d\theta) appears from...

It is found that Poyntings vector gives P = ExH = (mu0q2a2sin2(theta)/6pi2cr2)r This apparently leads to Total Power = (mu0q2a2/6pi2c)\int(sin2(theta)/r2)(2pir2sin(theta)d\theta) What I am unsure of is where the (2pir2sin(theta)d\theta) appears from. Can anyone help?

A point charge inside infinite dielectric material 1. The problem statement, all variables and given known data A point charge is an infinite medium of dielectric material having a relative permittivity \epsilonr. <--- epsilon(sub r). Find the electric field vector and the potential function...

Homework Statement Given that the electric field in a certain region is E = (z+1)*sin(Φ)aρ + (z+1)*ρ*cos(Φ)aΦ + ρ*sin(Φ)az V/m, determine the work done in moving a 4 nC charge from (4,0,0) to (4,30°,0). Homework Equations W = -Q*int(E·dl) The Attempt at a Solution Here is what I...

So I am playing around with the differential form of Gauss's Law: \nabla \cdot \vec{E} = \frac{\rho}{\epsilon_0} Starting off simple with a point charge, the electric field is: \vec{E} = \frac{1}{4 \pi \epsilon_0} \frac{q}{r^2} \hat{r} And the divergence, in spherical coordinates...

I've been working on this for a little while now (in CGS units), and am not really sure where I've gone wrong at in calculating the potential, so I've come here! Here is the problem: What is the potential caused by placing a point charge Q at the center of a dielectric sphere (\epsilon2)...

Homework Statement The surface of a sphere of radius a is charged with a constant surface density \sigma. What is the total charge Q' on the sphere? Find the force produced by this charge distribution on a point charge q located on the z axis for z > a and for z < a.Homework Equations The...

1. A point charge Q is held in the center of a charged ring. Half of the ring is charged uniformly with charge 2Q and the other half with 4Q. When the point charge is released, it accelerates toward infinitum. What is the ultimate speed of the point charge? 2. Homework Equations [E=F/q]...

Homework Statement Four identical charges are placed at the corners of a square of side side L. Find the magnitude total force exerted on one charge by the other three charges. Express your answer in terms of the variables Q, L and appropriate constants. where did the L root2 in the...

Homework Statement a point charge of .04144 uC (micro C) is inside a pyramid. determine the total electric flux through the surface of the pyramid in units Nm^2/C Homework Equations The Attempt at a Solution i really don't know, i don't feel like there is enough information given.

I was hoping people might be able to provide some insight into the following fairly basic scenario (not homework/school related). Imagine a positive point charge on the x-axis. Also on the x-axis, to the right, is an electric dipole, with finite spacing, pointed along the x axis, with the...

Homework Statement Three identical point charges of 2.0x10-6C are placed on the x-axis. The firs charge is at the origin, the second to the right at x= 50cm, and the third is at 100 cm mark. What are the magnitude and direction of the electrostatic force which acts on the charge at the...

Homework Statement The z=0 plane is covered with the uniform surface charge density, \rho_s=10^{-9}, while at the same time the point charge q=10^{-9} is located at (0,0,1). Where can an electron be place so if released, it will not move. Homework Equations...

Homework Statement In below figure, the three particles are fixed in place and have charges q1 = q2 = +e and q3 = +2e. Distance a = 6.00 μm. What are the magnitude of the net electric field at point P due to the particles? http://www.geocities.com/imfrrreal/22-36.jpg Homework Equations...

Hi Friends I am student of BsCs- 1st Semester, I am facing problem to solve a question of physics. I have tried my best to solve it but I am fail, can anyone do it for me I will thank to him. Here Is The Question Find the force on a positive point charge q located a distance x from the...

Homework Statement Four charges are placed on the corners of a rectangle. What is the resultant force on the positive charge (a = 1.5 m, b = 0.5 m, q = 1.1 × 10-9C)? (see attached drawing) Homework Equations Im having problems summing the forces using superposition The Attempt at a...

If there's a point charge at the origin, I want to find two closed surfaces such that the flux through one of them is zero while the other is not. I know this may seem trivial but I just want to make sure I understand the question. My answer would be that to get a zero flux, the closed...

Homework Statement I need some help solving this question, it is the last one I have to do and I'm not sure how to solve it. A point charge (m = 1.0 g) at the end of an insulating string of length 53 cm is observed to be in equilibrium in a uniform horizontal electric field of 9000 N/C...

Sorry for the poor title - I'm not entirely sure how to describe the type of problem! Homework Statement A charge of -4.00 x 10-6 C is fixed in place. From a horizontal distance of 55.0cm a particle of mass 2.50 x 10-3 kg and charge -3.00 x 10-6 C is fired with an initial speed of 15.0m/s...

Homework Statement This may be simple, but I don't seem to get the right answer: An electric field \vec{E}=100,000\hat\imath\;{\rm N}/{\rm C} causes the 5.0 {\rm g} point charge in the figure (Intro 1 figure) to hang at a 20^\circ angle. E = 100,000 N/C, point charge weighs 5 g...

[solved] electric potential: point charge in a hollow charged conductor Homework Statement A hollow spherical conductor, carrying a net charge +Q, has inner radius r1 and outer radius r2 = 2r1. At the center of the sphere is a point charge +Q/2. d) Determine the potential as a...

Homework Statement Four point charges have the same magnitude of 3.1 x 10-12 C and are fixed to the corners of a square that is 5.3 cm on a side. Three of the charges are positive and one is negative. Determine the magnitude of the net electric field that exists at the center of the square...

Homework Statement Consider a conducting spherical shell with inner radius 0.8 m and outer radius 1.3 m. There is a net charge 3 μC on the shell. At its center, within the hollow cavity, there is a point charge 3 μC. Determine the flux through the spherical Gaussian surface S, which has a...

Homework Statement A point charge is at the center of a conducting hollow sphere, with radius 0.011m, that is within another conducting hollow sphere of radius 0.041m. The point charge is Q0=+4.30e-6 C, the inner sphere has a net charge of Q1=-1.70e-6 C, and the outer sphere has a net charge...

Homework Statement 3 Point charges are fixed in place in a right triangle. What is the electric force on the +1.0 nanoC charge due to the other two charges? Basically you have 3 charges in a right angle as decribed, let's call them A, B, and C. In the upper left you have A, +0.8 nanoC...

A general problem you run into during an E&M class is the one involving a point charge a distance from a charged sphere. In cases where the point is far enough away from the sphere, the system can be treated like two points. In my case I have a point charge "q" a distance "z" away from the...

Homework Statement The distance between the oxygen nucleus and each of the oxygen nuclei in an H2O molecule is 9.58*10^-11m; the angle between the H atoms is 105 degrees. Find the electric field produced by the nuclear charges (positive charges) at the point P at a distance of 1.20*10^-10m...

Hi I think I figured it but I'm not sure. Here's the problem: How Much Work In Fig. 25-34, how much work is required to bring the charge of +5q in from infinity along the dashed line and place it as shown near the two fixed charges +4q and –2q? Take distance d = 1.40 cm and charge q = 1.6 ×...

Homework Statement A point charge q_1 = 3.45 nC is located on the x-axis at x = 1.90 m, and a second point charge q_2 = -6.95 nC is on the y-axis at y = 1.20 m. What is the total electric flux due to these two point charges through a spherical surface centered at the origin and with radius...

A point charge, Q=+1mC, is fixed at the origin. How much work is required to move a charge, q=+8(micro)C, from the point (0,4meters) to the point (3meters,0)? I was unable to derive anything. I guessed at around 40J. Correct? If so HOW! lol

Good day to everybody, I got stuck at certain (basic) question regarding Lienard Wiechert (LW) potential of a point charge: In Heitler's great book "Quantum Theory of Radiation" (I've used the edition from 1954), on page 18, there is a familiar statement that: \frac{e}{r}|_{t-r/c} is not...

Homework Statement Find the surface charge induced on an infinite conducting plate by a point charge +q at a distance a from the plate. The Attempt at a Solution As you probably know, this problem can be solved using the well-known fact that the induced electric field is equivalent to...

Consider a sphere of radius a with dielectric constant epsilon. A point charge q lies a distance d from the center of the sphere. Assume d > a, calculate the potential for all points inside the sphere, and outside the sphere. The problem is to be solved with an expansion of Legendre...

If you calculate W, the amount of work it took to assemble this charge configuration if the point charges were initially infinitely far apart, you will find that the contribution for each charge is proportional to {kq^2}/{L}. In the space provided, enter the numeric value that multiplies the...

Homework Statement what is the electric field at point A (0,12) if there is charge c of 8*10^-9 coulombs at (16,0) and a charge d of 6*10^-9 coulombs at (-9,0) determine x and y components of electric field (see diagram) Homework Equations electric field e = kq/r^2 where k is 9*10^9...

Homework Statement A point charge of 2.0 10-9 C is located at the origin. How much work is required to bring a positive charge of 4.0 10-9 C from infinity to the location x = 30.0 cm? and it requests the answer in J Homework Equations W=-q2(delta)V DeltaV = Ke q1/d where...

Hi, I have derived the electric potential equations inside and outside the sphere due to a point charge q placed a distance b way from the sphere's center. The potentials are given by: \Phi_{in}(r,\theta) = \sum^{\infty}_{n=0} A_{n}r^{n}P_{n}(cos\theta) and \Phi_{out}(r,\theta) =...

Hi, A simple question: Is the electric field of a point charge infinite at the charge itself? Coulomb's Law clearly seems to say so, but I just want to be certain. Thanks

Homework Statement Two particles are fixed to an x axis: particle 1 charge -2.00x10^-7 at x=6.0cm and particle 2 at 2.00x10^-7 C at x=21.0cm. Midway between the particles, what is there net electric field? Homework Equations E=kq/r^2 The Attempt at a Solution Ok so I drew the...

Homework Statement There is an equilateral triangle with one point charge at each vertex. The point charges have charges of +Q, +2Q, and -4Q. The length of one side of the triangle is L. Determine an expression in simplest form for the voltage at a point halfway between the +Q and +2Q point...

A proton is moved at a constant velocity towards a stationary +3micro coloumb point charge that cannot move. The proton is initially 50 cm away from the point charge and the proton is moved until it is 35 cm away from the point charge. A) How much work was done on the proton? B) If released...

Homework Statement A point charge of mass 0.069 kg and charge q = +5.89 µC is suspended by a thread between the vertical parallel plates of a parallel-plate capacitor. If the angle of deflection is 22°, and the separation between the plates is 0.025 m, what is the potential difference...

[SOLVED] Finding the electric potential of point charge Homework Statement I want to find the electric potential at a distance r from a point charge. Here's what I'm doing: We have V = - \int {E \cdot {\rm{d}}{\bf{l}}} I find that V = - \int_\infty ^r {k_e \frac{q}{{r'^2 }}{\bf{r}}...