What is Charge: Definition and 1000 Discussions

Homework Statement Homework Equations \overrightarrow{F} = \frac{1}{4\pi\epsilon_0}\frac{qQ}{r^2}\hat{r} The Attempt at a Solution I found to hard summarizing all forces directly adding each to other. The solution of this problem is only matter of drawing the 13-sided polygon and forces...

Homework Statement Two particles A and B each carry a charge Q and are separated by a fixed distance D. A particle c with charge q and mass m is kept at the midpoint of A and B. If C is displaced perpendicular to AB by a distance x where x<<<D, find the time period of the oscillation of the...

Imagine that I have a straight, statically-charged, cylinder-shaped tube with arbitrary (ideally infinite) extent. The charge is distributed evenly over the tube such that the field inside the tube is zero. For convenience, let's line up the tube centered along the x-axis such that the...

Sorry if this has been answered already, i searched for a while. I know how to solve the problem of the potential of a point charge near a grounded infinite conducting plane, and a line charge near an infinite conducting plane. If the plane isn't necessarily grounded, say its at some potential...

In a diode, we have N side, P side, and a depletion region, made of positive and negative charged sides. N side and P side of the diodes are neutral charge. In N side there are free electrons. In the positive charged side of the depletion region, there are positively ionized atoms that "lack"...

Homework Statement Given 2 positively charged parallel plates with equal surface charge densities, calculate the electric field at a point outside the the parallel plates. Homework Equations E= (surface charge density) / 2(relative permittivity) for a single sheet. The Attempt at a Solution...

Homework Statement [/B] Consider an electron beam traveling with velocity v. The total current of the beam is I.The beam is of uniform charge density and has radius R. (a) Find E and B at r<R and r>R using Gauss' and Ampere's laws. ( This part is fine.) (b) Consider an electron in the beam at...

Homework Statement The Lorentz Force can be used to sort ions (atomic or molecular) based on their charge to mass ratio. This configuration has been used to separate isotopes and as a mass spectrometer. A beam of Strontium ions Sr+ is accelerated through a potential of 500 V and injected into...

Even with the charge screening effect it is exact. Is there an explanation in the standard model? Can the fact there are 3 families of particles be involved?

Homework Statement A charged parallel plate capacitor is connected to a battery. The plates of the capacitor are pulled apart so that their separation doubles. What happens to the charge and the amount of energy stored by the capacitor? Homework Equations Q = cV Ue = (1/2)(Q)^2 / c \Delta V...

Homework Statement Homework Equations F= (k*q*Q)/r^2 The Attempt at a Solution The answer key gives the answer as D. I thought it was C. If the net electric force acting on P is zero, doesn't that mean that the force between Q1 and P and the force between Q2 and P need to cancel each other...

Hi. I know how to use Gauss' Law to find the electric field in- and outside a homogeneously charged sphere. But say I wanted to compute this directly via integration, how would I evaluate the integral...

I am trying to formulate the Current Density for a Loop of wire with a diameter,d, current,I, and an cross-sectional Area of the wire ##\pi(d/2)^2##. With spherical coordinates (radial, azimuthal, polar) ##\bar j## = ##\frac{I}{\pi(d/2)^2}*cos \theta *sin \phi \hat x##...

1. 2. I'm totally lost on this problem. Tried guessing in several ways but couldn't come up with the right answer.3. Since I was totally mesmerized by this problem, I need someone to solve it and provide explanation of critical steps of the process. Can someone help me?

Homework Statement There is a finite line charge with length L = 1 meter and linear charge density λ = 1*10^-16 C/m. Point P is h = 70cm above the line charge and distance x from the right end of the line charge. The magnitude and direction of the electric field at point P must be found. The...

Homework Statement Consider the parallel plate capacitor(no figure). The capacitor plates have a separation distance d in the z-direction. The volume charge density is given by ρ_v. Find v(z).Homework Equations ρ_v = ρ_o*sin(pi*z/2*d) The Attempt at a Solution [/B] ∫(ρ_vdz) =...

Homework Statement A disc of radius R lying in the xy-plane is composed of an inner disc of radius R/2 carrying a uniform surface charge density +σ and an anulus (inner and outer radii of R/2 and R) carrying a uniform surface charge density -σ. Assume that the inner disc and the annulus are...

Ok, this might be a really dumb question, but I still am asking it: I was reading about gauss' Law when it comes to a hollow conductor with a (say) point charge inside it, and it seems intuitive to me that, in electrostatic equilibrium, the charges rearrange themselves to cancel the electric...

I get a gist of how electric charge comes about in string theory here, https://physics.stackexchange.com/questions/5665/electric-charge-in-string-theory How much needs to be amended to the above answer to understand how color charge comes about in string theory? I assume there are interesting...

Homework Statement I've seen many books writing the cosine rule like this: a^2 = b^2 + c^2 - 2bc cos A My electricity textbook for an electric field in a point between two charges says this: E resultant = root[E1^2 + E2^2 + 2*E1*E2*cos(angle between E1 and E2)] In the first equation it is -2...

Hi all, This question has been bothering me for some time, so here it is. I know that moving a charged particle, like an electron, generates a magnetic field. I know that moving electric charges in a circle (a loop of wire) generates a magnetic field. The question is, will a charge moving in a...

Cosmic rays are overwhelmingly positively charged. Hence, whatever is emitting them must be building up an enormous negative charge. So should we expect to see highly charged Reissner-Nordstrom black holes out there? Perhaps even near extremality?

How does one calculate an excess charge distribution across 100 mH single layer inductor with 30 Hz voltage at amplitude of 10 V ?

Homework Statement "Two very long uniform lines of charge are parallel and are separated by ##x=\frac{3}{10}m##. Each line of charge has charge per unit length ##\lambda = 5.2_{10^{-6}}\frac{C}{m}##. What magnitude of force does one line of charge exert on a ##y=\frac{1}{20} m## section of the...

Hello, I have just bought the static charge meter, Keyence SK-1000. Analog output is sent through two small cables denoted as: 1. Analog output (surface potential). 2. Analog output GND. The analog output can be set to one of the following values: NONE (OFF), -5 to +5V, 0V to 5V, 1V to 5V, 4mA...

Is the potential energy of a symmetric planar (x,y) charge distribution lower than any non symmetric distribution ? from the discussion on Gauss's law and symmetric charge distributions I would think so because the electric field could only be normal to the (x,y) plane in the symmetry case but...

Homework Statement Positive charge Q is distributed uniformly along the x-axis from x = 0 to x = a. Determine a. The electric field produced by the charge distribution Q at points on the positive x-axis where x > a. b. A point charge q is then placed at x = a + r. Determine force on q due to Q...

Why are these batteries stated as 12V batteries if often they have a reading of greater than 12V e.g 13 or 14 and when you rev the engine hard while in neutral and do a voltage test on some components in the car circuit you get a reading of much much greater like 40V! How is this working? Could...

Homework Statement Consider a ring of radius R placed on the xy-plane with its center at the origin. A total charge of Q is uniformly distributed on the ring. a) Express the volume charge density of this configuration ρ(s,Φ,z) in cylindrical coordinates. b) Express the volume charge density of...

Homework Statement A point charge ##q = −5.0\times 10^{−12} C## is placed at the center of a spherical conducting shell of inner radius 3.5 cm and outer radius 4.0 cm. The electric field just above the surface of the conductor is directed radially outward and has magnitude 8.0 N/C. (a) What is...

Homework Statement I just have a general question about Guass's Law and the cylinders above. I don't really understand what the difference is between the 2 cylinders? They are both charged, but one of them does not have an electric field inside the cylinder because it a conducting...

Hi For a 1200 watt tool, there are 20, 40 and 60 volt batteries, and in the case of a 2 amp hour (7200 Coulomb) battery, using energy = charge x voltage gives different values of stored energy for each of the three batteries, which are 144000, 288000 and 432000 Joules. Is this correct? Thanks

After solving a homework problem, I realized I don't know what to do when there's a dipole and a point charge but the distance from the charges in the dipole is greater than the distance from the center of the dipole to the charge. As my homework problem stated, with a little context added...

Homework Statement Two identical thin rods of length L carry the same uniform line charge distribution (charge per unit length) of . If the two rods are collinear (aligned along the same line), with a distance of d between their nearest ends, calculate the Coulomb force (magnitude and...

Homework Statement An infinitely long line of charge has linear charge density ##λ=4.00_{10^{−12}} \frac{C}{m}##. A proton (mass ##m_p=1.67_{10^{-27}}kg##, charge ##e=1.602_{10^{-19}}C##) is ##r_a=0.18m## from the line and moving directly toward the line at ##v=1000\frac{m}{s}##. Homework...

Hey there I'm trying to reconstruct the entire table of all Dirac bilinears under C, P, T and CPT transformations of page 71 and hit a wall on charge conjugation. It's a computational problem, really. Here's a specific problem: Equation 3.145 we have $$-i\gamma ^2 \left( \psi ^{\dagger...

Homework Statement A proton is at the origin and an ion is at x1 = 6 nm If the electric field is zero at x2 = -3 nm , what is the charge on the ion? Homework Equations for ion The Attempt at a Solution https://imgur.com/ryyuQBq I just have used all my attempts besides one. So I...

Homework Statement Point charges ##q_1=50 \mu C## and ##q_1=-25 \mu C## are placed 1.0 m apart. Where must a third charge ##q_3=20 \mu C## be placed so that the net force on it is zero? Homework Equations $$\vec F=\frac{1}{4\pi {\varepsilon}_0}\frac{|q_1q_2|}{r^2}\hat r$$ The Attempt at a...

Consider an electric charge Q with rest frame R and a closed conductive loop L with rest frame R'. Q is moving relative to L, and vice versa. In R, the loop is moving and receives no magnetic flux from Q thus no voltage according the integral form of Faraday's law. In R', the loop receives...

Two identical front surface mirrors are hung in a vacuum chamber with a high vacuum with a bit of bias of their mass wanting to lean into each other so they don't separate on their own. The metal surface is connected to a variable high voltage source. Both mirrors are connected to the same...

Homework Statement A charge Q=5.14 nC is located at the center is located at the center of a Gaussian sphere of radius R=10.0 cm . The sphere lies within a uniform upward electric field E=2100 NC The net outward electric flux through the sphere is What? Second problem (bonus round!) A...

Homework Statement A beam of electrons passes undeflected through two mutually perpendicular electric and magnetic fields. If the electric field is cut off and the same magnetic field maintained, the electrons move in the magnetic field in a circular path of radius 1.14 cm. Determine the ratio...

This is a question born out of a homework thread that lead to a discussion between @haruspex, @rude man, and myself. Link here https://www.physicsforums.com/threads/what-is-the-charge-of-each-conductor-afterwards.923909/ . I feel this question deserves its own thread and hopefully we can get...

Greetings! I'm new here and I think about this place as soon as I see what the statement asks. Homework Statement Considering the volumetric density ρv=(e-2r/r2), figure the total charge (ℚ) of the universe. Homework Equations [/B] ρv=ΔQ/ΔV -> (ΔQ ∝ ΔV) ℚ=∫v ρv dxdydz The Attempt at a...

Homework Statement Two identical conductors are brought into contact. Initially one conductor has a charge of +30 x10^(-6) C, what is the charge of each conductor afterward? Does it matter how the contact is made? Homework EquationsThe Attempt at a Solution Well since they are conductors...

Homework Statement Two positive charges q1 = q2 = 2.0 μC are located at x = 0, y = 0.30 m and x = 0, y = -0.30 m, respectively. Third point charge Q = 4.0 μC is located at x = 0.40 m, y = 0. What is the net force ((a)magnitude and (b)direction) on charge q1 exerted by the other two charges...

Homework Statement "A straight, nonconducting plastic wire ##x=9.50_{10^{-2}}m## long carries a charge density of ##λ=1.3_{10^{-7}} C/m## distributed uniformly along its length. It is lying on a horizontal tabletop. If the wire is now bent into a circle lying flat on the table, find the...

Homework Statement "Let there be two point charges ##q_1=3.5μC## and ##q_2=-3.5μC## located at ##(0,0.3 m)## and ##(0,-0.3 m)## respectively. What force do these two charges exert on a test charge ##Q=4.5μC## at ##(0.4 m,0)##?" *title should read "due to two point charges"* <Moderator's note...

Hi, initially I would like to share this link related to derivation of maxwell equation : http://www.physicspages.com/tag/amperes-law/ My question is : in this link, it states interesting situation in electrodynamics is one where the current density is constant in time, but the charge density...

Homework Statement You charge a parallel-plate capacitor, remove it from the battery, and prevent the wires connected to the plates from touching each other. When you pull the plates apart to a larger separation, do the following quantities increase, decrease, or stay the same? (a) C (b) Q...