Fields Definition and 1000 Threads

Hi I am in a debate with some creationists. They are claiming that the speed of light changes in strong gravitational fields and can be slower or faster. My view is there can be time dilation effects. For example light towards the centre ( a black hole ) will be red shifted, and away from...

A gauge field W_\mu is known to transform as W_\mu\to W'_\mu=UW_\mu U^{-1} +(\partial_\mu U)U^{-1} under a gauge transformation U, where the first term UW_\mu U^{-1} means it transforms under the adjoint representation. Can anyone explain to me why it means a transformation under the adjoint...

1) Do all conservative fields follow Gauss's Law? For all laws of the nature 1/R^n the field would be conservative but would follow Gauss's Law only when n=2. So a field may be conservative but would not follow Gauss's law? 2) Do all field that follow Gauss's Law conservative in nature? Are...

Hello all. I am currently studying electromagnetism with Griffiths' books, and I have already donde electrostatic and magnetostatics. Now I am reviewing Ohm's law en emf concepts, but I have a doubt: In griffths book, when explaining ohm's law and emf, it seems to me that he assumes...

Comets have what is called an "induced magnetosphere". Has anyone been able to document polarity in any of the observed comets magnetic fields yet ? If they have I'm curious how it relates to the orbital plane of the comet. I haven't been able to locate that info if it exists so just...

Good to see mathematics hitting the headlines this morning, with news of the first-ever female Fields medallist.

http://www.slate.com/blogs/the_slatest/2014/08/12/first_female_fields_medal_winner_maryam_mirzakhani_of_stanford.html Stanford Report, August 12, 2014 http://news.stanford.edu/news/2014/august/fields-medal-mirzakhani-081214.html Stanford's Maryam Mirzakhani wins Fields Medal Maryam...

Why are magnetic fields and electric fields still considered different phenomena? Doesn't relativity and QFT explain that they are the same thing. A photon is a photon, isn't it? I mean, what is happening when two magnets repel? They exchange photons. What happens when two electrons repel? They...

Homework Statement Calculate the magnitude and direction of the electric field at point Z in Figure 13, due to the charged spheres at points X and Y. Homework Equations E = kq1/r^2 The Attempt at a Solution Determine each vector component: Ex = (9.0x10^9 Nm^2/C^2)(50.0 x...

does anyone have a proof of this?

Homework Statement ##\nabla{F} = <2xyze^{x^2},ze^{x^2},ye^{x^2}## if f(0,0,0) = 5 find f(1,1,2)Homework Equations The Attempt at a Solution my book doesn't have a good example of a problem like this, am I looking for a potential? ##<\frac{\partial}{\partial x},\frac{\partial}{\partial...

Consider an equilateral triangle of side 15.6 cm. A charge of +2.0uc is placed at one vertex and charges of -4.0C uc each are placed at the other two, as shown in the diagram to the right. Determine the electric field at the centre of the triangle ANgle= 60 sides--> d1= d2=d3=0.156m...

I am reading Beachy and Blair's book: Abstract Algebra (3rd Edition) and am currently studying Section 6.5: Finite Fields, I need help with a statement of Beachy & Blair in Example 6.5.2 on page 298. Example 6.5.2 reads as follows:https://www.physicsforums.com/attachments/2858In the above...

I am reading Beachy and Blair's book: Abstract Algebra (3rd Edition) and am currently studying Theorem 6.5.7. I need help with the proof of the Theorem. Theorem 6.5.7 and its proof read as follows:In the above proof, Beachy and Blair write: By Lemma 6.5.4, the set of all roots of $$f(x)$$ is...

I am reading Beachy and Blair's book: Abstract Algebra (3rd Edition) and am currently studying Proposition 6.5.5. I need help with the proof of the proposition. Proposition 6.5.5 and its proof read as follows: In the proof of Proposition 6.5.5 Beachy and Blair write: " ... ... Since $$F$$ is...

I am reading Beachy and Blair's book: Abstract Algebra (3rd Edition) and am currently studying Theorem 6.5.2. I need help with the proof of the Theorem. Theorem 6.5.2 and its proof read as follows:In the conclusion of the proof, Beachy and Blair write the following: " ... ... Hence, since F...

i am studying finite fields and trying to get an idea of the nature of finite fields. In order to achieve this understanding I am bring to determine the elements and the addition and multiplication tables of some finite fields of small order. For a start I am trying to determine the elements...

I am reading Section 6.4: Splitting Fields in Beachy and Blair: Abstract Algebra. I am currently studying Example 6.4.2 on page 290 which concerns the splitting field of $$ x^3 - 2 \text{ over } \mathbb{Q} $$ . In Example 6.4.2, B&B show that the splitting field of $$ x^3 - 2 \text{ over }...

https://www.physicsforums.com/showthread.php?p=2881300#post2881300 According to the quoted thread above and according to textbooks and Wikipedia the phase between the E and B fields of an electromagnetic wave propagating in free space is zero. This assertion is based on the Maxwell equations...

Hi all, I am looking into induced electric fields by changing B fields inside layers of dielectric. For example, if a block of several layers of a dielectric material is placed inside a capacitor plate, the E fields inside each layer is shielded depending on the relative permitivitty...

I am wondering if it is possible to shield strong (1 Tesla) DC magnetic fields with high attenuation factor (10^4 or better) WITHOUT also shielding AC magnetic fields above frequencies of ~10kHz. I have looked at mu-metal, which as far as I can tell shields DC but also AC fields to some...

Hi guys! I was wondering if someone could me help to get a free electronic copy of R. Wangsness book "Electromagnetic Fields". I would like to point out that I am just looking for a book which does not violate copyrights.

Help required to understand the physics concepts What will be produced if mutual induction of electric and magnetic fields occurs? Thanks

Hello. I was going through the problems in the angular momentum chapter of the text "Problem Book in Relativity and Gravitation"-Lightman et al in preparation for a project and I came upon part (c) of problem 11.10. It basically starts with a family of observers with 4-velocity ##u^{\mu} =...

I am reading Joseph Rotman's book Advanced Modern Algebra. I need help with Problem 2.34 on page 101. Problem 2.34 reads as follows: -------------------------------------------------------------------- Prove that any two fields having exactly four elements are isomorphic...

E = - grad*phi - 1/c (dA/dt). phi is the scalar potential, and is given. How do I calculate the vector potential = A ? Is it A = (v/c) * phi ? If it is, then where is this equation coming from? Thank you.

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...

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...

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...