Fields Definition and 1000 Threads

Homework Statement I was reading in a book that, " For any function f(x) whose functional form changes from f(x) to f'(x), we can write \bar{\delta}f(x) = f'(x) - f(x) = {f'(x') - f(x)} - {f'(x') - f'(x)} =...

Is possible to compute indefinite integrals of functions wrt its variables, but is possible to compute indefinite integrals of scalar fields and vector fields wrt line, area, surface and volume?

Hello, I am having to find the rotational diffusion of a magnetic particle inside of water. I already have a diffusion coefficient but I do not know how to take into account the restoring force that the particle will feel from the magnetic field. The info that I know is: B-Field Strength...

Other laws in terms of circulation and flux Why others vector fields no are studied like the magnetic and electric fields? In other words, why others vector fields, like the gravitational and the hydrodynamic, haven't "supreme laws" based in the circulation/flux or curl/divergence?

After watch this video , I understood that for study the behavior of the vector field, just use 2 tools, the line integral and the surface integral, and actually too, the divergence and the curl. In accordance with this, the maxwell's equations are justly the line integral, the surface integral...

Apologize in advance for the long post! We are in this particular situation and, being a novice with electrical- related issues, would greatly appreciate opinions here. After a year long search, we found this nice home in Texas meeting all requirements my wife and I were looking for, and at...

this might be a dumb question, but, if spacetime isn't a field and gravity is a property of spacetime. then gravity isn't a field either? (at least not a quantum field.)

Hi this is my first thread since joining the website, so let me know if I am violating any rules here. I read a bunch of rules to follow in the website but don't think I can remember everything. I am reading chapter 18 on Feynman's Lectures on Physics volume 2 (electromagnetism). It talks...

Homework Statement Does the number of attached identical magnets linearly relate to the number of paper clips/bolts/nuts that are magnetically chained together? Homework Equations I have no idea. The Attempt at a Solution Yes they are linearly related? I am guessing that yes it...

Homework Statement 1. Use Gauss' Law to calculate the electric field at a radius of 5.0cm from the z-axis 2. Use Gauss' Law to calculate the electric field at a radius of 8.0cm from the z-axis 3. What is the surface charge density σmetal on the outer surface of the metal cylinder...

Hi, I am a year 12 student and I have some some questions about magnetic fields. Homework Statement Do all magnetic fields (in particular ones produced by electromagnets) have distinct poles? How does a force act an object carrying current under presence of a magnetic field. Homework...

Hi, I've read that the speed of em waves in the vacuum is the electric field component frac the magnetic field component, why and how can this be explained more easily ? Thanks

These days it seems like everywhere you apply one of the requirements is having "strong" and sometimes "extensive" "computational skills". Well I already started a masters in applied math (after my PhD in experimental physics = zero computational skills). Before starting the masters it...

In QFT, all particles can be interpreted as excitations of some fundamental quantum fields in the vacuum. This is the quantum picture. But in classical world, only photons and gravitons have classical counterparts. How to explain this? The common feature of these two is that they are...

Hi! What are some newly introduced Academic fields like Mechatronics Engineering and Business Informatics?

Vector fields generate flows, i.e. one-parameter groups of diffeomorphisms, which are profusely used in physics from the streamlines of velocity flows in fluid dynamics to currents as flows of charge in electromagnetism, and when the flows preserve the metric we talk about Killing vector fields...

Homework Statement What does it mean that basic arithmetic can be performed with two (non parallel) linear equations and that the resulting equation also intersects the same point? Proof and or anecdotal explanation would be much appreciated. Homework Equations If (α) 3y = 4x...

I am attempting to get a good definition of the word "information", as in "information can be transferred at most at the speed of light".) Here is my attempt so far. Please indicate if this seems adequate. Starting from the definition in information theory: Given a probability...

Homework Statement I have been trying solve this ask, but there is a problem. I don´t know how I can obtain an expression of infinity which is connected with angle. Picture is as Attach Files2. The attempt at a solution I think, I must use this equations AAB=m * ∫ * K dr = Δ Ek Is there...

Hi, I am having a question about diamagnetism. I understand that ferromagnets realign with external magnetic fields. I know that besides diamagnets like copper, bismuth, that all matter exhibit some diamagnetism to some degree. I wonder though if these paired electron filled orbits of...

So I was just looking at graduate EE specializations and found some that interests me. I was just wondering which ones would have the best job markets. Electronics Circuits & Systems: Analog Circuits or Digital Circuits Power Electronics & Power Systems: Power Semiconductor Devices, Power...

Sorry if this is not a very we'll written thread. I have already had to re-write this three times because of computer problems. I have cut out almost all of the text I had previously written and moved straight on to the main questions I have. Please be considerate of my young age, which is...

I know that the standard definition for a slope field is ##\frac{dy}{dx} = f(x, y)##, but and if the equation given is a second-order ODE ##a\frac{d^2y}{dx^2}+b\frac{dy}{dx}+cy=0## or a system of first-order ODEs ##A\frac{d\vec{r}}{dt}+\vec{b}=\vec{0}##, the definition for slope field continues...

Given a vector field f, I can compute the rotational tendency in the direction n (∇×f·n), the translational tendency in the direction t (∇f·t) and the divergence (∇·f) too. So, given a scalar field f, why I can compute only the directional derivative (translational tendency (∇f·t)) in the wanted...

Homework Statement A uniform electric eld exists in a region between two oppositely charged parallel metal plates. An electron is released from rest at the surface of the negatively charged plate and strikes the surface of the positively charged plate, 2.00 cm away, in a time 1.8 * 10^{-8} s...

I have a question about electrostatic fields! I was given these two equationsE= k [xy xˆ + 2yz yˆ + 3xz zˆ] E= k[y^2 xˆ+ (2xy+ z^2)+ 2yzzˆ] And asked to determine if either could be an electrostatic field, I'm not asking how to solve this problem but I'm not sure what defines an...

Every conservative vector field is irrotational? Every irrotational vector field is conservative? Every solenoidal vector field is incompressible? Every incompressible vector field is solenoidal?

Why aren't force fields such as magnetic, electric and gravitational fields considered as a violation to law of conversation of energy?? :confused:

What field would you say is the most exciting in engineering/physics? I'm defining engineering/physics very loosely, so don't worry if your field is more biology than physics or whatever. So anyway; Which has the most potential for financial profit and entrepreneurship? Which has the most...

Homework Statement Which one of the following statements best explains why it is possible to define an electrostatic potential in a region of space that contains an electrostatic field? A) Work must be done to bring two positive charges closer together. B) Like charges repel one another...

This is something that has bothered me a lot since I tend to overanalyze and worry alot. In college, I studied physics and math, but decided that I wanted to get into engineering, so I applied and got a job at a defense contractor. However, I was terminated quickly because I was unable to get an...

Hi, please help me .. How can I derivative covariant and contravariant fields? as in the attached picture Thanks.. http://www.gulfup.com/?tNXcaN w.r.t alpha

why all EM waves are sinusoidal ? or this is not true at all, i.e., EM waves of other waveforms do exist ? the above 2 questions are among the most vague in classical EM theory, of which i studied many topics in collage as an electrical engineering student, and i liked the subject so i kept...

I believe I understand the basics of some fields, but I am unsure about the correctness of all of my knowledge. - All particles are excitations of their field (If it's a fermion) and the field they mediate (If it's a boson) - Electron repulsion is created by the exhcnage of virtual photons...

Left invariant fields on a group G satisfies a lie algebra; say we have an n-dimensional Lie algebra for which the fields ##{X_1, \ldots , X_n}## is a basis. Let these satisfy the algebra ##[X_a, X_b] = c_{ab}^c X_c##. Suppose now that we have a Riemannian manifold with killing vectors...

Hi folks! I'll start by admiting that I'm a cockroach compared to Einstein or Hawking, and I think that due to Hawking's great mind, maybe he wrote the book in a way he found conspicuous. But I don't have Hawking's IQ, and for me is definitely harder to understand the concept of "Time...

Homework Statement Experiments show that a steady current I in a long wire produces a magnetic field B that is tangent to any circle in the plane perpendicular to the wire and whose center is the axis of the wire. Ampere's Law relates the electric current to its magnetic effects and states...

Capacitors are popular candidates for explaining electric fields. The phenomenon becomes really apparent with the aid of a leiden jar ...which is really just a capacitor. Anyways, as long as you're cranking the handle on the electrostatic machine, the charge is going to build and build until I...

Electric fields vs magnetic fields? Ok, so in class last week, I had asked my professor about using the Lorentz Force Law to solve a particular problem. When he responded with "we only have a magnetic force from the current in the wire, so we don't have to worry about an electric field," that...

This isn't a homework question, however I'm curious if displacement fields can simply be added to find the total displacement field at some point. My instinct tells me this should be true. For linear media, D=εE. Since electric fields can be superimposed upon each other, shouldn't the same be...

I've got one more year left to finish my undergraduate EE degree and I'm planning on continuing straight into a PhD. I've had the chance to work with a postdoc on remote sensing/space science research and I've really enjoyed it. I've also developed an interest in neuroscience and plasma physics...

Homework Statement Question 1. General Plane Waves. We may represent a general electromagnetic plane wave by (real part of the complex exponentials) E=E_{0}*e^(i*k*r-iwt) B=B_{0}*e^(i*k*r-iwt) Show that Faraday's Law becomes iwB0=-ik x Eo Homework Equations dB/dt=- curl of E The...

You're probably familiar with Gauss's laws in electricity,magnetism and gravitation: \oint_{\partial V} \vec{D}\cdot \vec{d\sigma}=q_V \\ \oint_{\partial V} \vec{g}\cdot\vec{d\sigma}=-4\pi G m_V\\ \oint_{\partial V} \vec{B}\cdot\vec{d\sigma}=0 \\ It is also known that the first two integrals...

Hello! Well, I guess it's all in the title, really. I was reading about k-essence, and it was described as a scalar field having a non-canonical kinetic term. I did a bit of browsing and couldn't find a clear explanation of what, exactly, a non-canonical kinetic term is. Any help would be...

I'm currently taking Physics II and had a question. I'd ask my professor, but he's out of town until Monday and this is driving me crazy. Anyway, we recently started learning about magnetic fields. So far, I'm grasping most of it no problem. One thing that is throwing me off though is how...

I have an idea for a research project in neurobiology but I have only a limited background in these fields (I currently work in web development). Is there any way to gain the necessary skills and have access to the right equipment to carry out the experiments I want to do without going back to...

Conceptual question help--Electric fields, potentials, etc. Homework Statement 1) Assume that the electric field E is equal to zero at a given point. Does it mean the electric potential V must also be equal to zero at this point? If not, provide an example to prove your answer. if you think...

I just though of this and though "it's abstract math meeting physics, so probably not". After looking up fields in several abstract algebra books I thought that maybe fields in physics were called as such in physics because they share something with the mathematical structure of fields in group...

Homework Statement Consider a line of length L=0.950 m and uniform positive charge per unit length λ=2.9 μC. Point A is a distance x=0.23 m from the center of the line, while B is the same distance from the line but a distance y=0.28 m farther along the line; point C is a distance z=0.050 m...

My class hasn't delved into Gauss's Law much besides describing conductors at electrostatic equilibrium to have no net electric field or force within itself. For the picture, the question is: What are the magnitudes of the electric fields at: 1) r = a 2) r = 3/2 a 3) r = b...