Electric field Definition and 1000 Threads

Homework Statement Hello, A 3.60cm x 4.50cm rectangle lies in the xy-plane. What is the electric flux through the rectangle if E=(80.0i + 50k) N/C ?Homework Equations Φ = E * A =EAcos(θ) The Attempt at a Solution My attempt: First convert the rectangle units from cm to m. 4.50cm = 0.045m...

Homework Statement Two large non-conducting plates of surface area A=.025m^2 carry equal but opposite charges Q = 75microC. What is the energy density of the electric field between the two plates. Homework Equations I wrote the equations on my attempt. This was a multiple choice problem...

http://imgur.com/48cLE6q I can't follow this. Did my teacher make a mistake? Why are all the charges 2?

I suppose that my main question is how to find the induced electric field given a time-dependent magnetic field, but i will demonstrate my question with an example: I constructed a simple magnetic field B = b*tz , permeating the whole space. The induced electric field will lie in the xy...

In the situation consisting of a steady current of 1A in an arbitrary closed path, what would the consequences be for the electric field if the drift velocity was non-uniform along the path due to non-uniform carrier density? This would be a case of a "uniform" 1 amp, but where the charge...

I get easily confused when asked questions about electric field. One question that is bothering me is... Is it possible to have 0 electric field at a point, but at the same point have electric potential? I've read that the answer is yes, there can be a potential without a electric field, but...

Hey guys, i just came across this on my classical physics course. So, I'm given that: E(z, t) = {E_{0}}sin(wt)sin(kz)\widehat{x}, and I'm supposed to find an expression for the associated magnetic field B. Usually, i just find the propagation direction, and do it's cross product with the...

Which one is correct?? 1) electric field calculated by gauss law is the field due to charges inside the closed surface. 2) the flux of the electric field through a closed surface due to all charges is equal to the flux due to charges enclosed by the surface

Homework Statement We want to calculate the field of a uniformly polarized sphere of radius=R Homework Equations V(\vec{r}) = \frac{1}{4 \pi\epsilon_{0}} \oint_{S} \frac{\sigma_{b}}{r} da' + \int_{V} \frac{\rho_{b}}{r} d\tau' The Attempt at a Solution i)I know that \sigma_{b} = P...

Hello. I have a doubt regarding the direccion of the electric field in a point from a source charges. Let be a charge in the left of the plane. In a point to the right of the charge, the direction of the electric field vector is to the right. If the charge is negative, the direction of the...

This question is somewhat relating to electronics but I think it fits better with physics. The leccture here (slide 13) shows that the gate to body capacitance (Cgb) in linear region is 0. However, there is no explanation at all. I tried to find the explanation from the reference book and got...

In a linear isotropic homogeneous dielectric, P= χε0*E, where E is the net electric field from the effects of both free and bound charges. But E=(σfree—P)/ε0 So E itself depends on P. My concern is, isn't this circular? How can the polarization density depend on a field that itself depends...

Homework Statement The electric field and the electric potential at a point are E and V respectively. (a) If E=0, V must be 0 (b) If V=0, E must be 0 (c) If E≠0, V cannot be 0 (d) If V≠0, E cannot be 0 Homework Equations [/B] E = V/d The Attempt at a Solution [/B] I basically substituted...

Homework Statement Consider the electric dipole seen in the notes. (a) Using integration, derive an expression for the magnitude of the electric field produced by the dipole at any point along the x-axis. Electric Dipole: http://labman.phys.utk.edu/phys136/modules/m5/images/electr5.gif...

What will happen to the force between the capacitor plates (Will increase or decrease or remain constant) if we introduce a dielectric between them? As per the answer given the physics textbook , the force will remain same? But as per my understanding the force should decrease since electrical...

Question : Find the electric field at the centre of a ball of radius R with volume charge density rho = a.r, where a is a constant vector and r is a radius vector drawn from ball's centre. Relevant Equations and attempt at solution : I used the basic formula for electric field due to...

Homework Statement An electron with velocity ##\vec{v}_0=8.7*10^4(m/s)## (in the î direction) passing through an area with a uniform magnetic field ##\vec{B}=0.80 T## (in the negative k̂ direction). There's also a uniform electric field in this area. What is the magnitude and direction of...

sir, we know that the electric field lines are perpendicular to the surface of the conductor ,it means charges are rest on the surface of the conductor ,there is no work done. if we create an electric field such that the electric field lines are at a different angle to the surface of the...

If I attach a battery to two parallel plates to create an electric field between the plates, will the electric field last for the lifetime of the battery?

Homework Statement An electric field with a magnitude of 2.5N directed to the left, acts on a negative charge of -5.0C. Determine the electric field in which the charge is located. Give. FE=2.5N q=-5.0CHomework Equations FE[/B]=qε The Attempt at a Solution ε[/B]=2.5N/5.0C=0.5N/C. I don't...

Homework Statement . Homework Statement If the electric field does negative work on a negative charge as the charge undergoes a displacement from position a to b within an electric field then the electrical potential energy is? ANSWER: positive Homework Equations none The Attempt at a...

Homework Statement During a thunder storm, movement of water molecules within clouds creates friction which causes the bottom of the clouds to become negatively charged. This means that the bottom of the cloud and the ground begin to act like parallel plates. Once the electric field between the...

Homework Statement A cube side length a=2 has one vertice at the origin of the referencial. an electric field is present described as follows: E(x,y,z)= (2xz) i + (x+2) j + (y(z^2-3) k Find the flux through the cube My cube's front face is at (0 to 2, 0, 0 to 2) Homework Equations flux=∫E.dA...

Hello, Is it possible to derive the electric field of a dipole antenna mathematically? Does it look like a pure dipole far away? I am experimenting with these things and they are a bit mysterious to me. Thanks for your answers!

Metals have a work function which is the minimum energy needed to ionize an electron. I assume that the energy need is simply the energy difference of the two highest energy levels of a particular metal. This is all well and good and can be accomplished by absorbing a photon of that specific...

Homework Statement there is a square on the XoY plane, centered at the origin (just outlines of the square) it has a charge Q (Q>0) and side 2L, i must evaluate the electric field along the z axis. see attached image Homework Equations E=k*q/r^2 The Attempt at a Solution So first i divided...

I don't have a single problem, my teachers use this a lot. a few examples, are an uniformely charged circle and a point charge in the middle, where if you move the point charge a small distance perpendicular to the circle, it would begin to oscilate, and i need to find the frequency of...

Hello all, I can't figure out why it is impossible to have a radial electrical field within a solenoid. My gut tells me there would be one. For that matter, I also don't understand why there is no radial component surrounding a current carrying wire. Considering gauss' law has not helped me so...

Homework Statement Given an electric field in vacuum: Find the magnetic field under condition that |B| -> 0 as t -> infinity. Homework Equations I clearly have to use Maxwells equations to obtain the electric field here. Our equation for B has to satisfy them. More specifically Faraday's law...

Hello all. I am working on a research project involving the Stark effect and its application in molecular guides and came across a bit of math in a paper that I don't understand. In this paper http://arxiv.org/abs/physics/0310046 there is an equation in the introduction concerning the electric...

If a time varying magnetic field exists in vertically downwards direction in a region A, an electric field is induced in the direction perpendicular to it i.e. in horizontal plane. How to find the direction of the E field in the horizontal plane?What factors decide the direction of the E field...

Homework Statement In the figure two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have excess surface charge densities of opposite signs and magnitude 7.76 × 10-22 C/m2. What is the magnitude of the electric field at points (a) to the left of...

Homework Statement Charged metal sphere hanging on an isolated thread of negligible mass is put in a homogeneous horizontal electric field so that the thread makes a 45 degree angle with the el. field. What angle does the thread with the sphere close with the el. field after we remove 40% of...

Homework Statement Let ρ(r)= Qr/πR4 be the charge density distribution for a solid sphere of radius R and total charge Q.For a point 'P' inside the sphere at distance r1 from the centre of the sphere, the magnitude of electric field is ? A) 0 B) Q/4πε°(r1)2 C) Q(r1)2/4πε°R4 D)...

If the distance between the plates of a parallel condensor is 4mm and the potential difference is 60 volts . Now if we increase the distance between the plates to 12mm , then Why the electric field does not get decrease , instead of that potential difference between the condensor becomes 180...

Homework Statement To derive Potential Energy for dipole p in Electric Field E. 2. Homework Equations Potential Energy is the work done by the external agent in turning the angle of the dipole from the U=0 position to another position against the influence of the electric field applied...

Hi, i'm looking for an explanation to this answer of a past paper that I'm doing, it's from OCR (A level) G485, question 1 b ii) the question on top, and answer on bottom i don't understand why would the point experience a negative electric field strength when it's getting closer to a...

Homework Statement Calculate the electric field at point P (refer to visual): Homework Equations I follow everything - except how the limits of integration for the u-integral ( ) are arrived at? The Attempt at a Solution u=x2 is the smallest value u can have, and u=x2+R2 is the greatest...

The first part of the above image is the question from the text, and below that is information from the solutions manual. I understand why we broke the components up into the x and y, I understand how we triangulated the distance between the center of our coordinate system and the charge to get...

Hello. The first image is the question, the second image is from the solutions manual. I don't understand why these answers are negative. Anyone have a clue?

Homework Statement Calculate the magnitude of the electric field at the center of a square 42.5cm on a side if one corner is occupied by a −38.2μC charge and the other three are occupied by −27.0μC charges. Homework EquationsThe Attempt at a Solution E=k(q/r^2) the direction of the electric...

Homework Statement A +1.0 μC charge is placed at point X. A +4.0 μC charge is placed at point Y, 50 cm from X. How far from X, on the line XY, is the point where the electric field strength is zero? Homework Equations E = Q/4πε0r2 The Attempt at a Solution I know that the electric field is...

I had a thought about electric fields created by charges Look at this picture: Point ##B## is at the half the distance between ##q## and ##2q##. What I am trying to prove/disprove That there might be actually a point (##A##) near of charge ##2q## that might have an electric field stronger than...

So I know I have a misconception in one of these ideas and I would appreciate it if someone could correct me and thoroughly explain my error. Say I have two parallel plates connected to a battery, now there will be an electric field with magnitude, V/d between these plates. Now if I place a...

Using electrical potential energy =1/4πεo Q1Q2/r , a particle further away from nucleus has lower magnitude of energy Using coulomb's law, a particle further away from nucleus experiences weaker attraction, hence less energy is needed to maintain orbit* around that e-shell compared to a...

1. If e.m.f is NOT a force, but actually energy – and e.m.f is measured in Voltage – then why is p.d. (V) NOT used up? Since we know energy *does* get used up by the component. I know the electrons are just the medium – energy carriers – but Voltage doesn’t mean number of electrons; it means...

Homework Statement Calculate the magnitude of the electric field at the center of a square 42.5cm on a side if one corner is occupied by a −38.2μC charge and the other three are occupied by −26.9μC charges. (This part done) Choose the correct direction of the electric field at the center of...

I am trying to find the electric field of a hollow, open-ended, thin-walled cylindrical conductor. I am trying to solve something regarding LINACs: Assume we have an isolated, hollow, open-ended, thin-walled cylindrical conductor, with a net charge. The net electric field within the...

Homework Statement Two concentric cylindrical conducting shells of length L are separated by a vacuum. The inner shell has surface charge density +σ and radius ra. The outer shell has radius rb. Using Gauss’ Law, as a function of radius r find: The direction and magnitude of electric field...

Homework Statement Homework Equations E = kq/r2 V = -∫ E ⋅ ds W = -Vq The Attempt at a Solution a) I just summed up the electric fields: +ek/a2 +ek/a2 -ek/a2 so I get +ek/a2 as a result. Not sure if this is correct since -e has a y component so I was thinking to use sin but not sure which...