Charged Definition and 1000 Threads

I am new to General Relativity, so this question might sound silly. I know that the source of gravitational field is the stress-energy tensor. What I wonder is how do I find the spacetime metric, gmn caused by a stationary charged particle? What is the stress-energy tensor of a stationary...

Hi, I've been thinking about the concept of charged black holes. What I'm wondering is this; if light cannot escape a black hole, and photons are the bosons of the EM force, then is it meaningful to describe a black hole as having a 'charge'? If the photons can't escape the black hole, then no...

Homework Statement Ernest Rutherford in his lab at McGill University, Montreal, fired alpha particles of mass 6.64 * 10^-27 kg at gold foil to investigate the nature of the atom. What initial energy must an alpha particle (charge +2e) have to come within 4.7 * 10^-15 m of a gold nucleus...

I have a charged insulating marble -- let's say I used an electrostatic generator to get it up to 1 coulomb, and it weighs 1g (don't make me say 9.8mN). I have it in an insulating "box" whose walls and ceiling are very far away. I have it sitting still for a long time, so its E field is ~1/r^2...

I know that if you have alternating current in a wire, it will produce electromagnetic waves since the electric and magnetic field change direction continuously as the wave propagates, and that the wave direction, orientation of the E component, and orientation of the B component will all be...

Homework Statement Identical thin rods of length 2a carry equal charges, +Q, uniformly distributed along their lengths. The rods lie along the x-axis with their centers separated by a distance b > 2a. Find the force, F, exerted by the left rod on the right one. Left rod's center @ (0,0) → rod...

Black holes only emit hawking radiation which is black body radiation. If black holes only emit photons then the black hole can never get rid of charge which means it can never get rid of all its mass. Does this means black holes also emit charged particles?

Hi all, I am trying to out what happens when a gravitational wave caused by a monochromatic, electromagnetic plane wave interacts with a charged particle. As we all know, the electromagnetic wave causes the particle to follow a figure of eight shaped path (in the particles rest frame anyway)...

Homework Statement Homework Equations DON'T KNOW The Attempt at a Solution I can honestly say I've never been this confused by a question. At first my mind automatically went to a=qE/m since I have both charge and mass, but it became apparent that the equation was irrelevant...

Homework Statement A charged cork ball of mass m is suspended on a light string in the presence of a uniform electric field, as shown in the figure below. When E = (A + B) N/C, where A and B are positive numbers, the ball is in equilibrium at the angle θ. (a) Find the charge on the ball...

At the end of the derivation, it is given The electric fiel due to elementary ring at the point P is dE = [2∏rσdrx]/[4∏epsilon zero (x^2 +r^2)^(3/2) ] To find the total E due to disc is given by ∏σx/4∏ε∫(2rdr)/(x2 + r2)3/2 I am stuck with the calculus done here to arrive at the...

Homework Statement A solid insulating cone has a uniform charge density of rho and a total charge of Q. The base of teh cone had a radius of R and a height of h. We wish to find the electric force on a point charge of q' at point A, located at the tip of the cone. (Hint: You may use the...

... with constant charge density σ = Q/((pi)a^2) The Electric field is, after some calculation, is given by E_p below: z is the z-axis, and a is the radius of the disc. Now for the questions at the bottom of the page, here are my thoughts: σ is independent of a because as a->2a, Q->4Q, and...

See attachment. I don't why a charged particle in a uniform magnetic field will move in a circle. Why can't it just continue straight in the direction its going until another force acts on it?

Homework Statement Two flat charged plates create a uniform electric field (E). What happens to voltage (V) when the distance (d) is doubled? Homework Equations Voltage in uniform electric field: V = E*d Capacitance equations: V = Q/C C = K * A/d The Attempt at a Solution...

An electron is accelerated through 2.4 x 105 V from rest and then enters a uniform 1.7 T magnetic field. What are the maximum and minimum values of the magnetic force this particle experiences? QV = 0.5mv2 F=QvB Basically, I've got a final value from the above equations, but I'm not...

Homework Statement The problem can be found in Jackson's book, I think in chapter 1 problem 3 or something like this. I must determine the charge distribution of a uniformly charged disk of radius R in spherical coordinates (I've done it in cylindrical coordinates and had no problem). The...

I'm a year 12 physics student and I have a keen interest in the inner workings of a magnet. I know that magnetic fields are created by the motion of charged bodies. 1. Is this somehow related to the how magnets create their fields, within their structure at an atomic level? I've heard that...

1. How much work is required to assemble eight identical charged particles, each with charge q, at the corners of a cube of side a? Explain, based on your answer, whether or not this configuration is stable.

Homework Statement A disk of radius R has a uniform surface charge density σ. Calculate the electric field at a point P that lies along the central perpendicular axis of the disk and a distance x from the center of the disk. Homework Equations Electric field due to a continuous...

Say we have one spin-less electron in a box in the ground state. Say we have dials on the outside of the box that can vary mass and charge of the spin-less electron. Suppose we start with one spin-less electron in a box with m and e set to as near zero as we please, but not zero. As m and e go...

It is known that if a charged particle accelerates then it emits electromagnetic wave (energy). If so then this means that the work we do on particle, W=F*s, doesn't all go to particles kinetic energy, E=0.5*m*v^2. Then this means that Newton's F=m*a doesn't hold for charged objects, particles...

Homework Statement Two positive charged spheres, with masses m = 2.0 g and with the same charge 2 µC are connected by a rope that is a distance of 5 cm. The charged spheres are at rest and the system is in static equilibrium. Homework Equations N/A. The Attempt at a Solution The...

It has been stated that a charged particle in the vicinity of a magnetic field experiences a force given by F = qV x B, which states that there is no force when its velocity is zero. It also shows that only the particles direction can be changed, not its kinetic energy. My question is this...

For my electronics work I have a question to answer: "A 1000V source is used to fully charge a 1μF capacitor. The capacitor is then disconnected from the source and connected to two additional capacitors (2μF and 8μF) as shown in the circuit schematic below. a) Calculate the final voltage...

Homework Statement A thin charged rod of length L lies along the x-axis as shown in the diagram below. The charge on the rod is distributed with a density of λ= c x (C /m) where c is a constant. What is the potential at a point (0,y)? (Your answer should be in terms k, c, L, and y). See...

My textbook (Halliday & Walker) explains that a charged conductor (a solid, of an arbitrary shape) in electrostatic equilibrium will have the electric field inside be 0 and all electrons will be on its surface. It proves this by saying that if the electric field inside was not 0, the free...

If a charged particle passes through a magnetic field it will be deflected according to the right hand rule, i.e. VxB. What if the magnetic field lines are parallel to the velocity of the particle? Will the particle still be deflected?

Homework Statement Hi everyone and thank you in advance for your time. I just had this problem on a physics exam (that everyone in the class bombed, and I mean everyone, including the best students). I honestly couldn't care less about the grade, but I really want to understand where I went...

Homework Statement A Vbatt = 1.5 V battery stores Ubatt = 2.25 kJ of energy. I want to replace this battery with a charged capacitor that stores the same amount of energy and puts out the same voltage. That is, I want a capacitor such that UC = 2.25 kJ and VC = 1.5 V. What must the capacitance...

Homework Statement A metal sphere with radius r_a is supported on an insulating stand at the center of a hollow, metal spherical shell with radius r_b. There is charge +q on the inner sphere and charge -q on the outer spherical shell. Take the potential V to be zero when the distance r from the...

An iron arrowhead has an initial charge of 2.100e-6 C. How many electrons are required to give it a charge of −2.82 μC? I know that e (the elementary charge) = +/- 1.602E-19 C And N is the number (or excess charge) I tried solving this problem 2 ways. The first way: (2.100E-6 -...

Homework Statement In case of having a conductor (spherically shaped and uncharged) and an irregularly shaped hole inside it with a charge at an arbitrary point, I am asked to find the electric field right outside the conductor sphere. Homework Equations Gauss's law ∫EdA=...

If you go to the relativistic Hamiltonian, what allows us to go from \dot{\vec{P}} = - \frac{\partial \mathcal{H}}{\partial \vec{x}} = e (\vec{\nabla} \vec{A}) \cdot \dot{\vec{x}} - e \vec{\nabla} \phi to \frac{d}{d t}\left(\frac{m \dot{\vec{x}}} {\sqrt {1 -...

Lets say I am standing in the middle of a charged ring. And I am standing on a turn table. Now I start to rotate in the center. From my point of view do I perceive a B field. I mean I would have a velocity component.

Homework Statement There are three charged sheets with various charge densities. The following link shows a diagram, and solutions (not mine; these are some professor's solutions but I don't understand them yet): http://www.phy.syr.edu/courses/PHY212.08spring/HW/WHW-3.pdf Draw vectors at...

Homework Statement An electron orbits a 3.0 cm diameter metal ball 5.0 mm above the surface. The orbital period of the electron is l2.0 micro seconds. What is the charge on the metal ball? r=1.5cm or .015m R=.02m (.015+.005) Orbit=12*10^-6s Homework Equations E=(kq/r)R which gives...

A positron and an electron are simultaneously fired from paralle particle accelerators a distance d apart, with equal velocity v. One calculation says that each one will, being a moving charged particle, induce a magnetic field B=\frac{\mu_0 q v}{4\pi d^2} and since the other is moving in...

Homework Statement Two capacitors C1 & C2 are independently charged to potentials V1 & V2. Then the two capacitors are connected to each other, where each positive plate is connected to the other's negative plate. What is the final charge on capacitor 1 in terms of C1, C2, V1, V2? Homework...

Homework Statement Two tiny spheres of mass m = 7.90 mg carry charges of equal magnitude, 72.0 nC, but opposite sign. They are tied to the same ceiling hook by light strings of length 0.530 m. When a horizontal uniform electric field E that is directed to the left is turned on, the spheres hang...

Homework Statement A mass m that has net electric charge Q is oscillating along the x-direction on one end of a spring (whose other end is anchored) of relaxed length s0. Suppose that someone then swirches on an electric field E  that is uniform in space, constant in time, and which points...

A 20-cm radius ball is uniformly charged to 80 nC. (a) What is the ball’s charge density (C/m3)? (b) How much charge is enclosed by spheres at points 5, 10 and 20 cm from the center? (c) What is the electric field strength at points 5, 10 and 20 cm from the center? ATTEMPT: part a: i...

Two Capacitors are connected in series (3 microfarad and 6 microfarad) with Vab=10V. Battery is disconnected and the loose ends of wire are connected. What happens to the potential difference?Would it be zero..charge? I can't figure it out...sounds like a short circuit?

Homework Statement An infinite sheet of charge that has a surface charge density of 25.9 nC/ m2 lies in the yz plane, passes through the origin, and is at a potential of 1.32 kV at the point y = 0, z = 0. A long wire having a linear charge density of 81.1 nC/ m lies parallel to the y-axis...

Homework Statement Two concentric spherical conducting shells of radii a = 0.360 m and b = 0.540 m are connected by a thin wire, as shown in the figure below. http://capa.physics.mcmaster.ca/figures/sb/Graph25/sb-pic2550.png If a total charge Q = 10.6 µC is placed on the system, how much...

Homework Statement Two charged spherical conductors are connected by a long conducting wire, and a charge of 22.0 µC is placed on the combination. If the first sphere has a radius of 4.49 cm and the second has a radius of 5.68 cm, what is the electric field near the surface of each sphere...

Homework Statement Consider a sphere uniformly charged over volume, apart from a spherical off-center cavity. The charge density is ρ, radius of the sphere is a, radius of the cavity is b, and the distance between the centers is d, d < a-b. (a) Find the total charge and the dipole moment...

I apologize for the brevity but the forums logged me out and ate my entire post. I just want to get the information written down this time. Homework Statement We have two charged beads, 12.0cm apart. What are their maximum velocities when released? Bead A: -5.0nC, 15.0g Bead B: -10.0nC...

Homework Statement The work done by an external force to move a -8.5μC charge from point A to point b is 15x10^-4 J. If the charge was started from rest and had 4.82x10^-4 J of kinetic energy when it reached point b, what must be the potential difference between a and b Homework Equations...

Hi, I am a high school student and I'm planning on entering a regional science fair with an experiment involving electrolytes, magnets, and electric currents. However, I don't understand electromagnetism well enough to fully understand everything that would be going on in the experiment, and as...