Lorentz force Definition and 193 Threads

I would be very grateful if someone would kindly explain this generalization of the Lorentz force law to the special relativity domain. I am not entirely sure if what I have jotted down is exactly as the speaker intended to convey. But here is what I have got. Please bear with me...

Homework Statement An electron in an electric field E = 3.0x107 ex NC-1 and a magnetic field B = 3.0 ez T has velocity v = 1.0x107 (2ex - ey) ms-1. Calculate electromagnetic force on the electron. Homework Equations F = q (E + v X B) where q = e- = -1.6x10-19 C The Attempt at a...

I understand that for a fixed massflow the minimum amount of power required to generate a thrust is: P = Massflow * ∫v dv = massflow *0.5* [v2^2 - v1^2] However, is it possible to produce the same thrust with less power using the Lorentz force in an electromagnetic accelerator? If so, how can...

I am trying to understand how the Lorentz force affects bulk fluid motion when I have an applied electric field (y-axis), applied magnetic field (x-axis) and bulk fluid velocity (z-axis), all orthogonal to each other. I understand that if the fluid was at rest, an electrostatic force would...

Hey everyone, I'm trying to make sure I did this question right. Any ideas would be greatly appreciated. Thanks! Homework Statement The general force that bends the electron in the e/m experiment is known as the Lorentz force, F = q(E + v x B), where force F, electric field E, velocity v...

Homework Statement An electron in electric & magnetic fields; E = 3.0x107 ex NC-1 B = 3.0 ez T has velocity v = 1.0x10^7 (2ex-ey) Calculate em force on the electron.Homework Equations I'm using the Lorentz force law here. F = q(E + v X B) I have an example solution using vectors to evaluate...

Homework Statement An electron in a magnetic field B=2.0T(ex-ez) has velocity v=(2.5x107 ms-1 (ex-ey) a) calculate magnetic force on electron at that instant b) what is the magnitude of this force Homework Equations I am using the Lorentz force law. F = q(vXB) & evaluating the directions by...

So my friend and I were going through problems and this came up... Consider 3 straight, infinitely long, equally spaced wires (with zero radius, separated each by a distance d), each carrying a current I in the same direction. blah blah blah... part c) asks us... If the middle...

Hi everyone, I was wondering, does the Lorentz force can be used to get the self force of a particle over it self? I'm in doubt because the fields that one uses to compute the force, in the lorentz force expression, are the external fields but one can compute the Liénard-Wiechert potetials...

Someone asked me how Faraday's Law of Induction and Ampere's Force Law, both which form part of Maxwell's Equations, are related. Ampere's Force Law is derived from the Lorentz Force Law. They are entirely compatible with Faraday's Law of Induction. Here's how...The Lorentz Force Law states...

Greetings everyone(New guy here!). I wanted to know something about "Lorentz force". A magnetic force causes a loop carrying current to rotate and torque is created due to those forces. Are magnetic fields doing work in this cause? Based upon this law: [SIZE="4"]F = q(E + v + B)...

A charged particle - like an electron - has a magnetic moment. This moment changes depending on where the electron is. If you apply a magnetic field to an object with a magnetic moment, it experiences a torque. It turns. This turning motion is not included in the overall motion of the...

Is it valid to analyse the equation of motion of an electron in its instantaneous rest-frame in which it feels a force from the electric field only with no magnetic Lorentz force component?

Essentially I'm wondering about coupling with Maxwell's equations. It seems that, for application of the Lorentz force equation to make sense, the E and B fields used should not include the E and B fields generated by the charge in question, since a charge won't exert force on itself. However...

Homework Statement If an electron is stationary in a magnetic field, will it experience a Lorentz force? Homework Equations The Attempt at a Solution The total vector force (Lorentz force - F) is F = Fe + Fm = Q(E + u X B) The Lorentz force can also be written in terms of...

Hi, I have a particle moving in a static electromagnetic field in which E and B have the following components: E=(Ex, 0, 0) B=(-Bx, 0, 0) and both depend on z, namely Ex(z) and Bx(z). The particle is moving along z with constant velocity v=(0, 0, vz). If I want to express Lorentz force...

Btw I am obtaining all these equations from chapter 5 of Griffiths text. Lorentz force law is: Fmag = ∫I(dI x B) Does this give the force on a current carrying wire due to an external magnetic field? (i.e. has nothing to do with own wires magnetic field) I think the answer is yes since the...

when a charge particle is moving in electric and magnetic field, a force exert on this particle is Lorentz force. when this force apply to this particle, it accelerate and we know accelerated charge particle radiate. when a particle radiate an electromagnetic wave ( photon ) lose it's...

hi i was wondering whether the lorentz force is just caused by the fact, that moving charges produce a magnetic field, just like every current does, and this magnetic field interacts with the magnetic field in the environment, that causes the force or whether the lorentz force has nothing to...

'One example of the Lorentz force is that, if two parallel wires are carrying current in the same direction, the wires will be pulled toward each other. The Z-pinch uses this same effect; the entire plasma can be thought of as many current-carrying wires, all carrying current in the same...

Homework Statement This problem asks you to work out the dielectric function of a gas of particles with number density n, charge q, and mass m, with a steady magnetic field applied in the z direction. Assume an electric field in the x direction, E_x(t)=E_xe^{-i \omega t} is applied. Write...

Homework Statement A raindrop carrying a charge of 25x10-12 coulombs falls at a velocity of 5 m/s between the poles of a permanent magnet. It passes through a 50 mm long region in which the magnetic field density of 0.9 T is directed horizontally. 1) determine the lorentz force of the...

Studying in the Heisenberg picture, we have \frac{\text{d}x_i}{\text{d}t}=-\frac{\text{i}}{\hbar}[x_i,H]=\frac{1}{m}\left(p_i-\frac{q}{c}A_i\right) where the last bracket is known as the kinematic momentum \pi . Now, to find \frac{\text{d}^2{\bf{x}}}{\text{d}t^2} I do the following...

Given that the Lorentz force on a current when E=0 exists only at right angles to the current, such would not change the speed of the current, but only its direction. Also, when the current is parallel to a magnetic field line, no deflection of the current by the magnetic field occurs. A magnet...

i am looking for a why. not a description of how to calculate or how to find its direction. i came across this question in a school question. "why does the wire move up" and then i thought. is there really a 'why'? or it just happens?

Let us consider a fixed Carthesian reference frame (x y z) with a charged (+) particle locate in its origin. Moreover, let us consider two parallel conductors of infinite lenght, carrying the same current I (in the same direction y). The two conductors move at constant velocity from the origin...

Hello all, I am having a slight conceptual problem in rationalizing what happens when a current-carrying material is exposed to an orthogonal magnetic field. The Lorentz force experienced by the moving charged particle is generally given by (dropping directional notations for clarity): F = q(E...

In elementary electromagnetics, we learned the formula of Lorentz force. While I am always confused about the origin of this formula. Because when studying electrodynamics, I always thought Maxwell equations incorporate all information we need to know about electromagnetic interaction, but I...

The "v" of the Lorentz Force If I have a rotating magnetic dipole that is rotating at an accelerated rate, then it is clear that the "v" of the "B" increases around the axis of that dipole's rotation. In addition, this should affect the "v" of the "q" affected by the "B", but the force induced...

Sorry if I should be posting as homework, but it's not homework anymore and I'm just curious about the answer. My question is simple and doesn't require answering the actual homework question I had. If there is a force on a charge in one inertial frame of reference, will there also be a force...

Hello, I've been trying to puzzle this one out and even the mighty internet has not been particularly helpful, so here goes: Say you have a current carrying copper wire perpendicular to a magnetic field. Let's give some values for clarity: the length of the wire is 1m, the current is 3A...

Basically the question is about a penning ion trap. You need to use the equation for the Lorentz Force, which I have. It says the trap electrodes have a potential: V(x,y,z) = A(2z^2 - x^2 - y^2); There's a superimposed uniform B-Field B = B(z hat) It then asks you to write down an...

Homework Statement an electron accelerated from rest through potential difference V1=0.868 kV enters the gap between two parallel plates having separation d = 21.9 mm and potential difference V2= 91.2 V. The lower plate is at the lower potential. Neglect fringing and assume that the electron's...

Lorentz force is explained or demonstrated using Fleming's Left Hand Rule or the Force equation using cross product. What I'm trying to ask here is, why is the direction fixed using the Left Hand Rule or the equation? Why is the direction here and not there? Equation and rules are the...

Homework Statement Show that the Lorentz force law follows from the following variational principle: S=\frac{m}{2}\int\eta_{\mu\nu}u^\mu u^\nu ds-q\int A_\mu u^\mu ds Homework Equations Definition of Field Strength Tensor Integration by Parts Chain Rule & Product Rule for Derivatives The...

Can anybody help me that how to work out the direction of Lorentz Force? Should I work out from the formula? Thanks.

I am trying to establish whether the force defined by the Lorentz equation below is invariant under the Lorentz transforms: [1] F = F_E + F_B = qE + qvB In the context of this equation, [q] is moving with velocity [v] such that it is acted on by both an electric E-force and magnetic...

I'm having a bit of trouble understanding what exactly the lorentz force is. In this diagram here [PLAIN]http://img7.imageshack.us/img7/7065/helicinbfld.jpg I know its the force that's keeping the proton in that helicoidal trajectory so I can see its perpendicular to the direction of the...

Homework Statement Consider a particle of mass m that carries a charge q. Suppose that the particle is under the influence of both an electric field E and a magnetic field B so that the particle's trajectory is described by the path x(t) for a\leqt\leqb. Then the total force acting on the...

Homework Statement Question is E=(x,y,z) B=(x,y,z) v=(x,y,z) (in vector form) For all E,B,v find v(t) and r(t) v and r of course have their vector arrows. Homework Equations F=ma= qE + qv x B There is a hint to take second derivatives across and some terms will clear up. I was thinking more...

http://en.wikipedia.org/wiki/File:Magnetischer_Kreis.svg The attached image shows a magnetic circuit with a small air gap. The magnetic material on each side of the gap is attracted to the other side. I've seen the magnitude of the force calculated based on principle of virtual work...

Preface: If a bar magnet is cut in half, we are left with say N-S--cut--N-S allinged along the z axis. Then the S and N ends are attracted to each other. This attraction is due to the "fringing" or non-uniform B field of the poles. That is the component of the B field that is normal to the...

I'm a bit confused about how the Lorentz Force (as a law) stands in relation to the laws of Maxwell (independent of each other? dependent?). There are two concrete examples I can think of where they interfere with each other: 1: Lorentz Force & Faraday's Law of Induction Imagine a...

It is known that in a current carrying wire, exposed to a magnetic field, the wire will experience a force equal to the product of the field, the current and the length of the wire (where the direction of the force is orthogonal to both the field and the direction along the length of the beam)...

I have a few questions about this effect. If I have some semiconductor of N type in which I have electrical field in x direction, and magnetic field in z direction \vec{E}=E\vec{e}_x \vec{B}=B\vec{e}_z Then Lorence force is in the -y direction because in N type of semiconductor n>>p so...

The lorentz foce has been bothering me. Becouse it seems to sugest an abosolute velocity. Say you have tw parrellel wires, with equal current running in the same direction. According to Lorrentz force, they attract. Now, the two wires are plasma. The curents are running side by side, at...

Homework Statement Show that the 4-force law: F_u=q/c E_{uv}U^v leads to the usual Lorentz force law. Homework Equations F = E + v x B. The Attempt at a Solution What's U?

I'm wondering what happens (or if it makes sense) if in the formula \mathbf{F} = q (\mathbf{E} + \mathbf{v} \times \mathbf{B}) we replace v by Lorentz factor, that is \frac{1}{\sqrt{1-\frac{v^2}{c^2}}}. I realize that in the new formula I'm cross-producting a scalar with a vector, but I could...

This is doing my nut in. I'm looking at causes of errors in a rotating gradiometer. It uses a loop of superconductor formed so that the current in the loop is proportional to the gradient of the magnetic field threading the loop. I think that an error current will arise due to the Lorentz...

Reading Jackson this morning, where it was stated that the Lorentz force equations: \frac{dU^\alpha}{d\tau} = \frac{e}{mc} F^{\alpha\beta} U_\beta are sufficient to describe the motion of a charged particle in an external field, neglecting the effects of radiation. That radiation...