Electric Definition and 1000 Threads

Why in this derivation both the perpendicular electric field immediately above and below the boundary are pointing upwards? Why do we make this assumption and would it work if they are pointing in different directions?

My interpretation of this equation is "how much does the electrical potential energy changes when I move the particle a little bit"? Suppose that I have some arrangement of charges, with Q at x and q at x'. Then I move the charge q a little bit in the direction of Q (dx), it will require some...

Hi, While reading griffith introduction to electrodynamic I have stumbled upon this: I don't understand why when the pillbox hight goes to zero we have a discontinuity of electric field. On the figure 2.36 we can see the electric field penetrates the surface from below the plane and exits...

PREFACE: My first real post so please bear with me and my notation and layout. I tried to make it as easy on the eyes as possible... While I am fairly confident of my process thus far, I feel I may be straying from the answer a bit towards the end. Considering the short vertical electric...

Here is my line of thinking: I know A and B aren't correct since the work done would be negative since the electric force and displacement are in opposite directions. When calculating the electric potential energies to consider options C and D, I thought the initial electric potential energy of...

For (a), I got ##V(r)=0## For (b), using Gauss law I get the electric field in the region to be ##\vec E=\frac{kQ}{r^2}\hat r##, then: $$V(r)-V(b)=-\int^{r}_{b} \left(\frac{kQ}{r^2}\hat r\right) . (-dr ~\hat r)$$ $$V(r)-0=\int^{r}_{b} \frac{kQ}{r^2} dr$$...

Does anyone know how this electric hacksaw is called? I attach the video that shows how it is used. Thank you d.

I am looking for some neat way to visualize various fields in the space around the usual electronic components: a straight wire, a single turn circular coil, a multi-turn finite solenoid, and an infinitely long cylindrical solenoid. I can get the expression, either in their analytical exact...

Good afternoon! I would like to understand how the Faraday disk works and get answers to two questions. The working conditions are as follows: 1) we rotate the external circuit with a voltmeter relative to a stationary disk; 2) the external circuit is not in a magnetic field. Questions: 1) will...

I'm not asking for a solution, but for one of my homework problems, it is asking about a circular surface and a positive charge to the right of the surface. I just wanted to check if the net electric flux through the loop would be zero, as the charge is not enclosed by the loop. Is there...

(a) $$\varepsilon (t)=V_L+V_C$$ $$\varepsilon (t)=L\frac{dI}{dt}+\frac{q(t)}{C}$$ $$\varepsilon (t)=L\frac{d^2 q}{dt}+\frac{q(t)}{C}$$ (b) taking ##q(t)=e^{rt}##, $$0=L\frac{d^2 q}{dt}+\frac{q(t)}{C}$$ $$0=L.r^2 e^{rt}+\frac{e^{rt}}{C}$$ $$0=L.r^2+\frac{1}{C}$$ $$r^2=-\frac{1}{LC}$$ Is it...

I imagine the setup to be like this: the pendulum is moving horizontally, then it will experience electric force upwards so there is additional upwards acceleration, in addition to the acceleration from restoring force. Since the resultant of the two accelerations is not directed horizontally...

Griffith's keeps mentioning the case r<R and r>R blah blah blah. Ok. But what if r = R? My attempt at an answer: when I take the limit from outside the sphere, I get the case when r > R. When I take the limit from inside the sphere, I get the case when r < R. Left and side hand side limits do...

The answer key shows option D is correct. But I think option C is also correct. Which option is correct here?

For part a) we have $$ E = \frac{Qy}{4 \pi \epsilon_0 (x^2 + y^2)^{3/2} } = \text{constant} $$ I am stuck on part b). What should the shape of the volume?...

In Maxwell's equations, the electric field appears in both Gauss's Law and Ampère's Law. Do these refer to the same electric field, or are they different components of the overall electric field? I think Gauss's Law gives electric field 1 and Ampère's Law gives electric field 2. So the total...

Homework Statement: TE and TM polarization parralel question Relevant Equations: its a photo Hello, In the photo on the left bellow E-field is not parralel not to X nor to Z direction. to what exactly is it parralel? Thanks.

The relevant equation listed above as ##\vec{E} \left( \vec{r} \right) = \frac{1}{4 \pi} \int {\nabla’ \times \frac{\partial \vec{B}}{\partial t}}\frac{1}{\left| \vec{r} - \vec{r}’ \right|}\, d \tau’## Seems to me to be a natural consequence of the Helmholtz Theorem so I don’t see why it...

The thread was inspired by an article, "Here’s How Koenigsegg’s ‘Dark Matter’ Electric Motor Makes 800 HP" https://www.thedrive.com/news/heres-how-koenigseggs-dark-matter-electric-motor-makes-800-hp What is "raxial flux?" It's not a new genre of EDM...

Hi, I don't know if I have calculated the electric field correctly in task a, because I get different values for the Poisson equation from task b The flow of the electric field only passes through the lateral surface, so ##A=2\pi \varrho L## I calculated the enclosed charge as follows...

Suppose two orthogonal neighbouring orbitals ##|\phi _1 \rangle## and ##|\phi _2 \rangle## so that ##\langle \phi_1|\phi _2 \rangle =0##. Applying an electric field adds a new term ##u (c_1^{\dagger}c_1-c_2^{\dagger}c_2)## to the Hamiltonian which u is a constant potential. Obviously, we still...

Hi, I am reading Griffiths Introduction to electrodynamics. Currently I am solving problem 2.11 which asks to find an electric field inside and outside a spherical shell of radius R. Inside: $$\int{E \cdot da} = \frac{Q}{e_0} = |E|4\pi r^2 = \frac{Q}{e_0} = 0$$ The result is $$0$$ because we...

this is the field I was provided and this is the charge density that I have reached I tried to use this yet the output was different I also used Cartesian it gave me the same output as the spherical ones

Here's what I've tried. First of all, I assume that q is positive. For particle A, then, I can write $$q E -k {\left( x _{A }-x _{B }\right) }=m \ddot{x }_{A }, $$ where ##x _{A } ## and ##x _{B } ## are the coordinates of the particles relative to their equilibrium positions from the point of...

Homework Statement: circuits - terms Relevant Equations: - How exactly can the electric potential be constant between two points in a wire; (assuming that it is electron current); if the electron is moving from a region of high electric potential to a low electric potential because of the...

I did a thought experiment and I can't figure out what the mistake is. There is a system of 2 electric motors weighing 1 kg each with batteries in the Earth's orbit. The motors are rigidly connected by a 1-meter-long bar. If one motor starts rotating in one direction on a signal, the entire...

It seems that electric mining equipment is all the craze right now: Liebherr electric excavator Caterpillar 240-ton electric haul truck Liebherr and Fortescue partner on world’s first autonomous electric haul truck EPCA plans to convert 50-70 mining trucks to electric power annually Liebherr -...

Hello to everyone. I have some doubts about one problem of quantum mechanics. My attempt. I need to calculate the coefficient ##W_{ij}=<\psi_i | H' |\psi_j>## where ##H' = -eE(t)z## is a perturbation term in the hamiltonian and ##|\psi_i> = |\psi_{nlm}>##. We have four states and sixteen...

Suppose there is very long current carrying wire. A charged particle is present somewhere around it. The current in the wire varies with time, thus by biot-savart's law there should be time varying magnetic field. I want to know that will this time varying magnetic field produce electric field...

Hi, I wonder if someone can help with the following problem? We have a sealed box in space and inside the box is an electric motor with the stator attached to the box. The rotor arm is attached to the inner race of a bearing and the outer race of the bearing is also attached to the box. There...

My understanding of this question is that, if you have a proton standing against a positive electric field, and move it in the opposite direction of the field, you're putting in work and therefore should have greater electric potential energy. But that idea breaks down when you consider a...

I would like to discuss a few ways to apply derivatives in physics (I don't understand it fully). I don't need a full solution, I only need to understand how to successfully apply the derivatives First example, Thin insulating ring of mass M, uniformly charged by charge ##+q## has a small cut...

surfafce area = 0.502 E = -q/A2(en) = 3800 -q = 3800*(A2(en)) -q = 1.68*10^(-8) -q = 3.37*10^(-8) V = kq/r V = (9.0*10^9)(-3.37*10^(-8))/0.2 V = -1519 V

I did make the problem simpler by looking at the the part from d/2 down the upper plate here are my initial parameters I am making my size step be h since lowering it may make calculating harder I am especially getting weird results for the field and capacitance R = 0.1; % Radius of the...

Let's assume that we have a hollow sphere with holes at opposite ends of the diameter. What would be the field inside the hollow sphere? I know that we can look at this as the superposition of the hollow sphere without holes and 2 patches with opposite surface charge density. For some reason, in...

here is my attempted solution. ## d^2 = z^2 + \frac {L^2} {3} ## ## C ## is coulomb constant since the point is symmetric, only the vertical component of the electric field remains. So, $$ E = 3 E_y =3 \frac {C Q cos \theta} {d^2} $$ $$ E= 3 \frac {C Q z} {d^3} $$ thus part (a) is done ( i...

Today, I watched a video about electric field created by an infinite plate by Khan Academy. They were talking about the clever application of the Gauss's law in this case (the cylinder method), so I wondered if I could apply the same thing but to 2 plates. For example, let's say that the plates...

We take out "formulas" for electric potential from the relation $$V=\int E.dx$$ Some general formulas are : For a hollow sphere : ##\frac{Q} {4π\epsilon_0 x}## when x>R, x =distance of that point from the center And the problem is we just input the distance in sums to calculate absolute...

I understand the following .a conductor is made of atoms and atoms always strive to be at equilibrium and that's why the electric field inside a conductor is zero because the electros distribute themselves in such a way so that they are in equilibrium , yet they do produce an electric field...

q encolsed =0 Second case q enclosed q by gauss law At 2r

I have having trouble understanding Maxwell's Equations. Can anyone recommend some good book or website that can help me to understand these Equations? How can electric and magnetic fields travel perpendicular to each other? What causes electromagnetic waves to first radiate from its source? I...

The most common explanation I know is that anomaly cancelation implies the sum of electric charges of each particle must cancel generation-wise, so 3 Q(Up) + 3 Q(Down) + Q(electron) = 0, and electroweak doublets imply Q(Up) - Q(Down) = Q(neutrino) - Q(electron), so with Q(neutrino) = 0 it solves...

I tried resolving the semi infinite rods into arcs of 90 degree each placed on the three axes but that doesnt take me anywhere.... Alternatively I tried finding out the field at the point due to each rod but im unable to find the perpendicular distance from the point to the rod...I dont think...

Lambda = charge density I tried first taking out the field due to the circular arc and I got $$ (lambda / 4π (epsilon knot) ) (2 sin (theta)) $$ For reference this is the arc that was provided in the question of angle 2(theta) and the tangent What I dont understand is how can the fields be...

This is the general suggested approach given in a textbook. My question is why can I not directly write it in vector form? E1 vector + E2 vector =0 should be valid no? Why are they choosing to write E1 mag + E2 mag=0 Then find a vector form Then convert the magnitude equation into a vector...