Fields Definition and 1000 Threads

How can we align all the input fields of form vertically in justified position.For example like this form:

Hi all! I'm super lost on this homework question. I tried asking the professor but was kind of brushed to the side. My vector calculus knowledge is pretty limited (I had an unfortunately experience in that class). Anybody have any ideas on how to go about solving for this? It's a problem out of...

I've been given a copy of my friend's midterm exam from this same class from last term, and decided to take a crack at it to help study. One question type in particular really messes me up and it looks like the following. How would I go about solving these in the future? A solid insulating...

I am currently doing a PhD in theoretical physics (let's for simplicity say gravity and black holes). However, I have also in my free time been working a bit in a more applied field (let's say cold atom physics), and have been reasonably successful (in the sense that I have some publications...

My question is about Force Free fields in the study of plasma stability (in MHD regime): Consider an isolated ideal plasma in an equilibrium state (where the effect of selfgravity is negligible), from the Navier-Stokes equation we get that: $$\vec{\nabla} P = \frac{1}{c} \vec{J} \times...

Homework Statement Two large parallel plates are 0.8 m apart and generate an electric field of 12 N/C between them. At 0, 1/4, 1/2, 3/4, and full distance (0.8m), how much kinetic energy does a +0.25 C charge gain as it passes through each location? Homework Equations V = PE/q The Attempt...

Disclaimer: I'm not sure if this is the correct forum. An ideal conductor (ideal = no resistance) is essentially taking the electric field at one terminal and connecting it to the other terminal. Charge moves when it is in an electric field, electric field strength is in Volts per meter, or...

Are there any theories that have mixing between fields and space? For instance, a theory with mixing between two fields might look like: L_{int} = k \phi(x) \psi(x) Where mixing between a field and space might look like: L_{int} = k \phi(x) x What are the consequences of something like this?

Can someone please explain to me why, a changing magnetic field can produce an electric field and a changing electrical field can produce a magnetic field. Also how do magnetic fields originate, what causes them?

Are the E and M components of an E-M wave (at a given frequency) necessarily in phase in free space? A conductor? A dielectric material?

Homework Statement Hello. I am having trouble understanding this particular statement found in one of my textbooks. " Work done to move a charge along a line perpendicular to the field is zero" The Attempt at a Solution Field is a space around a charge where if we place any other charge...

Homework Statement Hi this is my first post I hope that my explanation is good. Now this is the explanation. Now I will provide the known values. So I start looking literature and some formulas to solve this and I found two different propagation constants. Gama and Beta. Homework...

I know Zwitterions contain both a positive and negative charge. As such, I know that the zwitterions will not migrate towards either pole of the field. My question is: will the zwitterions align with the electric field lines?

So I was thinking, if the body has its own electrical currents... especially in the brain, then the brain must have an electrical field that extends infinitely. If that is the case can the brains electrical field interact with the real world and influence it. So for example if the field was...

After the success of QM. They want to extend it to fields like electric field, electromagnetic field.. hence the initial attempt at quantum field theory (QED).. next they think particles like electrons can be treated the same.. hence the so called second quantization. Besides fields.. what else...

Homework Statement Define a structure VEHICLE which contains producer, model and chassis number. Store the content of a structure in binary search tree such that the key for storing contains all fields of a structure (producer has the highest priority, and chassis number has the lowest). Print...

Separate questions: 1. What is the mathematical formalism where one can transform between field and geometry or they both being emergence? 2. What is the mathematical formalism that can describe QFT but not using the concept of fields nor particles. What are they called and current attempts at...

Suppose I have electric field of the form ##\mathbf{E} = 3x\mathbf{i} + 3y\mathbf{j}##. Calculating the charge density gives me ##\rho = \epsilon_0 \nabla\cdot\mathbf{E} = 6\epsilon_0##. But now if I turn one of the components of the field in the opposite direction, for example ##\mathbf{E} =...

Does a superconductor experience any forces acting upon it when it is passed through a magnetic field?

In my electromagnetic theory book, there is a classification of vector fields, one of the 4 different type vector fields is "solenoidal and irrotational vector field" (both divergence-free and curl-free). If solenoidal and rotational vector fields are same thing, then it means the vector field...

In QFT particles are described by fields, but AFAIK these fields are mathematical since we don't measure values of fields at a particular spacetime. So what does it mean to say a higgs field exist! I mean it is one thing to say Higgs particle exists (in LHC), but I have not seen anybody measure...

Are electric and magnetic fields real or are they just mathematical manipulations? Of course, one could say that we do not care about whether they are real or not, the only thing which matters is that they are useful in describing various things. But we assign quantities like energy, momentum...

In a source-free, isotropic, linear medium, Maxwell's equations can be rewritten as follows: \nabla \cdot \mathbf{E} = 0 \nabla \cdot \mathbf{H} = 0 \nabla \times \mathbf{E} = -j \omega \mu \mathbf{H} \nabla \times \mathbf{E} = j \omega \epsilon \mathbf{E} If we are looking for a wave...

Consider a Majorana spinor $$ \Phi=\left(\begin{array}{c}\phi\\\phi^\dagger\end{array}\right) $$ and an pseudoscalar current ##\bar\Phi\gamma^5\Phi##. This term is invariant under hermitian conjugation: $$ \bar\Phi\gamma^5\Phi\to\bar\Phi\gamma^5\Phi $$ but if I exploit the two component...

Hi, In general relativity we have no general conservation of energy and momentum. But if there exists a Killing-field we can show that this leads to a symmetry in spacetime and so to a conserved quantity. Thats what the mathematic tells us. But I don't understand what's the meaning of an...

There is a recent article (Optics July 2015) claiming violation of Bell inequalities for classical fields: "Shifting the quantum-classical boundary: theory and experiment for statistically classical optical fields" https://www.osapublishing.org/optica/abstract.cfm?URI=optica-2-7-611...

I am a Mechanical engineering student planning to do masters in physics next year. I am interested in astrophysics and astronomy, but classical and quantum mechanics also interests me.If I take admission into a masters degree program in physics, would I be able to specialize in these fields?What...

I think the equation for the relationship of the E (electrical) and B (magnetic) fields in electromagnetic (EM) radiation is E=Bc, where c is the speed of light. I think this is correct, but what does it tell us? On it's face, it looks as though the B field (of a photon, say) is...

1. The magnetic field at point P due to a magnetic source S1 is represented by ==>. Can a bar magnet S2 be brought close to P so that the total magnetic field at P due to S1 and S2 is zero? Explain your answer.2. None3. Yes, this is possible if both fields at point P have the same magnitude but...

Recently I've had some discussions about time in GR. I've always read in different places that people usually want a spacetime to have a hypersurface-orthogonal timelike Killing vector field so that they can assign a time dimension to that spacetime. But Why is this needed? I can understand it...

In the absence of a sense of scale, will the gravitational fields of large objects be indistinguishable, one from the other?

Homework Statement Consider the ring of polynomails in two variables over a field K: R=K[x,y] a)Show the elements x and y are relatively prime b) Show that it is not possible to write 1=p(x,y)x+q(x,y)y with p,q \in R c) Show R is not a principle ideal domain Homework Equations None The...

As I understand it, you can create a concentrated magnetic field at a specific point by having two electromagnets in a cone shape, both pointed at each other. The cone effectively condenses the field, and is strongest at the region between the points of two cones. Is this understanding even...

Homework Statement The Question is here: imgur link: http://i.imgur.com/wIlUZMM.jpg Homework Equations U_c = \frac{\kappa \epsilon_0 A d E^2}{2} U_c = C \Delta V_c \kappa: dielectric constant \epsilon_0: permittivity of free space C: capacitance The Attempt at a Solution [/B] I...

Urs Schreiber submitted a new PF Insights post Examples of Prequantum Field Theories II: Higher Gauge Fields Continue reading the Original PF Insights Post.

Urs Schreiber submitted a new PF Insights post Examples of Prequantum Field Theories I: Gauge Fields Continue reading the Original PF Insights Post.

I assume that all the fundamental physics known - as of today - can be reduced to quantum general covariant fields (including spacetime itself to be seen as a field of those...). Now, sorry if my question is quite abstract and based on tomorrow's hypothetical new physics, but would it be against...

Hi guys! Sorry for all the questions on electromagnetism. My understanding is that an electric field exists in electric monopoles and dipoles, as well as moving magnetic dipoles, and magnetic fields only exist in magnetic dipoles and moving electric dipoles. Is this correct? There are 2 parts...

Does the (assumption of) ubiquitousness of EM fields explain single particle interference well/better? Below is a rough logic, however it maybe need modifications. The double slit or the mach-zehnder or any object changes the configuration of time-space and EM fields. The photon may not know...

Homework Statement http://postimg.org/image/vzhqi8er5/ Homework EquationsThe Attempt at a Solution I understand all the calculations here - http://www.physicspages.com/2012/10/18/coaxial-cable-with-dielectric/ I have one issue that is bugging me though - if λ charge density is distributed over...

I'm Indian and I've heard stuff that it is difficult to get into a good PhD program in the US/UK for string theory because the competition is more fierce than other fields. Furthermore,the likelihood for getting academic positions is even tougher(added to the fact that I'm from a different...

Hi all :) I am about to finish the chapter of electromagnetic induction in my class. And I taught my students that the electric field induced due to changing magnetic flux is different that the electrostatic field due to stationary charges(Now I am wondering would it be wrong if I used the...

Hello. There is one thing I can not find the answer to, so I try here. For instance, writing a general superfield on component form, one of the terms appearing is: \theta \sigma^\mu \bar{\theta} V_\mu My question is if one could have written this as \theta \bar{\theta} \sigma^\mu V_\mu ...

Hi. In GR , covariant differentiation is used because the basis vectors are not constant. But , what about in SR ? If the basis vectors are not Cartesian then they are not constant. Does covariant differentiation exist in SR ? And are for example spherical polar basis vectors which are not...

Hi all, This is for SQL queries, sorry ran out of space in the title. Say we are doing a query that includes a null field/attribute. Must we always use either an " Is null" or " Is not null" statement? Thanks.

I'm in my first semester at a JC and I'm trying to figure out what kind of physics I might want to pursue as a career. I know I love space, and I want to be able to apply my math towards it. What initially sparked my interest in physics was theoretical physics, however, I soon realized the job...

Homework Statement The problem deals with a charged (Q) rotating sphere around its axis (Ω_0) z^^ (z hat) of radius a. I'm asked to find the total angular momentum of the EM fields. 2. The attempt at a solution There is a solution posted to this question and I was just wondering why my...

Hi everyone, First, sorry if the question is stupid, I do not have any background in Physics. Just very curious. Potential energy due to gravity is: m * g * h Joules Now, suppose I lift a weight on Moon at a given height. I will have: 1.6 * m * h Joules I maintain it at that height and go to...

number of fields line originating from 1 C charge is it infinity as per the following video or 1/epsilon according to http://www.topperlearning.com/forums/ask-experts-19/calculate-the-no-of-field-lines-originated-from-a-charge-of-physics-electric-charges-and-fields-81114/reply My textbook...

Can a cylinder with 1 side open act as a faredey cage (which do not allow passage of magnetic field) when magnetic field are only coming parallel to the curved part