Conducting Definition and 562 Threads

i don't understand why in the solution of this exercise, the induced electromotive force / current is counterclockwise. Shouldn't it be clockwise? ##emf=-\frac {d \Phi_B} {dt} ## According to the picture the rod is moving upward, the magnetic flux (entering the page) is decreasing due to a...

After looking around a bit, I found that, considering the polar axis to be along the direction of the point charge as suggested by the exercise, the following Legendre polynomial expansion is true: $$\begin{equation}\frac{1}{|\mathbf{r} - \mathbf{r'}|} = \sum_{n=0}^\infty...

Homework Statement A conducting sphere has a radius of 2.25 m and carries a positive surplus charge of 35.0 mC. A protective layer of barium titanate is applied to the surface of the sphere to make it safe for laboratory workers nearby. Safety considerations dictate that the potential...

Homework Statement A neutral conducting cylindrical shell with inner radius b and outer radius c surrounds a charged insulated cylinder of radius a at its center whose volume charge density varies radially away from the center as ρ(r) = ρ0 (1− r / a) . A cross-sectional view is shown. (a)...

Homework Statement There is a capacitor (llenght ##L##) made of a conductor (cylinder of radius ##R_1##) and a cylindrical surface (radius ##R_2##). It is charged with a potential ##V_0##, then it is isolated. (There is vacuum between ##R_1## and ##R_2##) Now we insert a cylindrical...

Homework Statement A dipole ##\textbf{p}=p\mathbf{\hat{z}}## (oriented along the z axis for example) is parallel to a conducting grounded plane (xz plane) and is placed at a distance ##d## from it. I have to find the interaction energy and the force between the dipole and the plane. Homework...

Hi all. I need some help with the circuit attached. For the diode to conduct, at point X the voltage must be 0.6V minimum. There is an equation to find the minimum required voltage input, Vin to give 0.6V at X. What I don't understand is the right hand side of the equation; why is it...

Homework Statement 3. A spherical conducting shell is placed in a time-varying magnetic field. Is there an induced current along the equator? Homework EquationsThe Attempt at a Solution I don't know what is the right answer. I mean...why not? Is the magnetic field is changing, there should be...

Hello, could someone help answer this question for me: How would the path of a conducting sphere (i.e. AL) be affected as it passes through a strong uniform magnetic field orthogonal to the direction of motion. I believe the Lenz effect/Eddy currents will create a magnetic field opposing the...

Homework Statement Hello all, not really sure what to title this. Heres the question: Ceicil sets a trap. According to ceicil, all she has to do is somehow attach a conductive bar with resistance 1Ω to the turkey and then get it to walk along a wire loop in a region of 100T magnetic field (as...

Suppose a straight current carrying wire is immersed in a uniform electric field along its axis. For this problem, please don't worry about complete loops or return paths, just consider a segment of straight wire carrying a current. Since external electric fields don't get inside conductors due...

Homework Statement Consider an electromagnetic field in an empty space in the region ##0 \leq z \leq a## with the following non-zero components: $$E_x = -B_0\frac{\omega a}{\pi}\sin\left(\frac{\pi z}{a}\right)\sin\left( ky-\omega t\right)\\ B_z = B_0\frac{ka}{\pi}\sin\left(\frac{\pi...

Homework Statement A) Use Gauss's Law to derive the electric field in all space for a non-conducting sphere with volumetric charge distribution ρ=ρ0r3 and radius, R. B) Repeat when there is a concentric spherical cavity within the non conducting sphere with radius, A. Homework Equations...

Homework Statement You have a conducting sphere that is in equilibrium, it has a cavity in it with positive charge +q. If you bring another charge +q2 near the outer edge of the conductor does the total surface charge on the wall of the cavity, q(int) change? There is an image attached that...

Homework Statement You are given a non conducting rod carrying uniformly distributed charge, -Q, that has been bent into a 120° circular arc of radius, R. The axis of symmetry of the arc lies along the x-axis and the origin is at the center of curvature of the arc. (a) in terms of Q and R...

Homework Statement Homework Equations The Attempt at a Solution for part ii) a<r<b E=0 I am not sure what will be the difference between the formulas for the electric field for a<r and a>b I think the formulas will look the same: The only difference that I can think of is that when r<a...

Homework Statement Two infinite sheets of charges are placed parallel to each other. If the sheet on the left is non conducting and have a uniform charge density 3(sigma) and the one on the right is conducting and has a uniform charge density (sigma). If the area on both plates is 1m^2 then...

Homework Statement A conducting rod makes contact with rails to complete a circuit. If the rails are 50 cm apart ina uniform magnetic field B = 0.38 [T] directed out of the paper. The total resistance of the circuit is R = 9 [ohms] and is constant. 1) what is the magnitude and direction of EMF...

Homework Statement Below is a diagram of an infinitely long non-conducting rod of radius, R, with a uniform continuous charge distribution. The uniform linear charge density of this line is lamba1. The rod is at the center of an infinitely long, conducting pipe. The linear charge density of...

Homework Statement A small conducting rod of length l moves with a uniform velocity v in a uniform magnetic field B. Explain how the end Y becomes positively charged. Homework EquationsThe Attempt at a Solution I know the concept, a force will act on the conductor which will push the...

I got into a little debate about the nature of a problem where you put a giant solenoid around the equator of Mars to give it a magnetic field (not my idea, I like futuristic things but... there are probably better things to worry about). Anyways, I got into a debate about the effect of the...

Homework Statement Homework Equations ##Q_{net}=Q_1+Q2## The Attempt at a Solution ##Q_{net}=Q_1+Q2## ##-15 = +5 + Q_2## ##Q_2=-15-5 = -20nC##

Hi suppose you have a conducting liquid in a strong magnetic field, and this is pumped in a continuous loop through two electrodes, why does this produce a D.C current? My thinking is a simple answer, and that is that the D.C current is produce because the fluid is moving in one direction...

When current flows through a copper wire, for example, a magnetic field is produced. What is the polarity of that field? I've seen an example with special relativity and how a positive charge would be deflected. Does that mean the field is negative to a stationary object? Every video I watch...

Homework Statement (Problem 2.38 From Griffth's Electrodynamics): A metal sphere of radius R, carrying charge q, is surrounded by a thick concentric metal shell (inner radius a, outer radius b). The shell carries no net charge. Find the surface charge density ##\sigma## at R, a, and b...

Homework Statement The problem states: "A point charge q is located at a fixed point P on the internal angle bisector of a 120 degree dihedral angle between two grounded conducting planes. Find the electric potential along the bisector." Homework Equations ΔV = 0 with Dirichlet boundary...

Homework Statement a) State the boundary conditions for the electric field strength E and electric flux density D at a planar interface separating two media with dielectric constants ε1 and ε2. b) A parallel plate capacitor with a plate separation d is filled with two layers of different...

Hi colleagues, I need your help to figure out some subtle theory problmes I have about this topic. I was thinking about a system composed by a conductive sphere (not grounded) under the effect of a pont charge placed near the sphere. As I know we need two image charges to satisfy the boundary...

Homework Statement Homework EquationsThe Attempt at a Solution Option (a), because the potential is 0 on the surface, and potential due to point charge is positive so there must be negative charge on the surface. Since opposite charges attract each other, there is an attractive force...

Homework Statement Two conducting hollow spheres are are placed concentrically, the inner sphere have a radius ra = 5 cm and the outer sphere have a radius rb = 15 cm. The charge on the inner sphere is qa = 4 · 10−7 C and qb = −4 · 10−7 on the outer sphere. (a) Use Gauss’s law to find the...

Homework Statement A small but very powerful bar magnet falls from rest under gravity through the center of a horizontal ring of conducting wire, as shown in the figure below (on the left). The speed-versus-time graph, in arbitrary units, of the magnet will correspond most closely to which of...

Homework Statement A current I flows along the surface of a hollow conducting cylinder. The radius of the cylinder section is r. By using Ampere's law, show that the magnetic field B outside the cylinder is B=\frac{\mu_0}{2 \pi} \frac{I}{r} Homework Equations Ampere's law...

Homework Statement Consider a conducting sphere of radius ##R_1##. Inside it there is a cavity, spherical in shape, with it origin at the same point as the conducting sphere and of radius ##R_2## ##(R_1>R_2)##. Assume there is a point charge equal to ##+Q## at the origin. Use Gauss law to...

Homework Statement Using the method of images discuss the problem of a point charge q inside a hollow grounded conducting sphere of inner radius a.Find (a) the potential inside the sphere (b) induced surface-charge density (c) the magnitude and the direction of force acting on q is there any...

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...

Homework Statement Consider a disc (negligible thickness) of radius R with its center at the origin. Assume that the disc has a radially symmetric surface charge density given by ##σ(s) = \frac{A}{\sqrt{R^2-s^2}}## at a distance s from the origin, where A is some constant. You can take it for...

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...

Homework Statement Two thin conducting plates, each 25.0 cm on a side, are situated parallel to one another and 5.0 mm apart. If ##10^{-11}## electrons are moved from one plate to the other, what is the electric field between the plates?Homework Equations $$\vec E(P) = \frac{1}{4\pi...

Homework Statement A uniformly magnetized and conducting sphere of radius R and total magnetic moment m = 4\pi MR^3/3 rotates about its magnetization axis with angular speed \omega. In the steady state no current flows in the conductor. The motion is nonrelativistic; the sphere has no excess...

Hi, I am looking for some information regarding maximum current density in conducting mediums, such as a conducting fluid. Say that we have a setup like the figure that I have attached. We are looking down on a conducting medium with a uniform magnetic field coming out of the page and the...

1. Homework Statement We have an infinitely long wire with charge density ##\lambda## located at ##x=0,y=h##. We also have a semi-infinite strip of a conductor ##|x|<a/2, y<0##. We need to find the potential in all space. The hint is to use conformal maps. Homework Equations $$\nabla^2 = 0$$...

Homework Statement Homework Equations 3. The Attempt at a Solution [/B] I have drawn this diagram using MS paint, could you please tell me some other software in which I can draw and insert greek symbols, too ?Let me take the origin at O. ## \hat r \left(\alpha\right) ≡ \hat r\text{ at...

Homework Statement I uploaded the Ex. 3.2. Homework EquationsThe Attempt at a Solution On the spherical surface, the potential due to q'' at center is going to be constant. q''= V0 R\kLet's say that the potential of the neutral conducting sphere is V0. Now, to calculate the force of...

Homework Statement A + q = 5 pC charge is uniformly distributed on a non-conducting sphere of radius a= 5 cm , which is placed in the center of a spherical conducting shell of inner radius b = 10 cm and outer radius c = 12 cm. The outer conducting shell is charged with a -q charge. Determine...

Homework Statement A metal disc of radius R rotates with a constant velocity ω about its axis. FInd the potential difference between the centre and the rim of the disc if: a)the external magnetic field is absent b)the external magnetic field of induction B is directed perpendicular to the disc...

Homework Statement (The complete problem statement and solution are inside the attached picture) Two isolated, concentric, conducting spherical shells have radii ##R_1=0.500 m## and ##R_2=1.00 m##, uniform charges ##q_1=2.00 mC## and ##q_2=1.00 mC##, and negligible thicknesses. What is the...

Given a charged sphere, the electric field within it is zero at every point. Why is this? Why is not merely zero only at the center? If a sphere is conducting, then its charge is all across the surface. If electric field is inversely proportional to distance from charge squared, won't the field...

Homework Statement A point charge +q is placed outside a grounded conducting sphere of radius a. which of the following is ##not## true. a) There is an attractive force between the sphere and the charge b) The induced surface charge density on the sphere is not same everywhere c) The electric...

It’s been a long time since I took E&M courses and even thought about these things, but a current thread has led me to question the location of excess charge on a conducting shell. Given that there are two surfaces to which charge can move, why doesn’t some charge also locate on the inner...

Homework Statement Homework Equations None The Attempt at a Solution My thinking was that the positively charged sphere would repel the electrons to the far side of the neutral sphere, creating a repulsive force between the two spheres until they touch and the charge is shared. Since the...