Fields Definition and 1000 Threads

Hi, I'm done with my second year of electrical engineering and am interning at nVidia. So far all I see is people in cubicles debugging code and compiling kernels. Of course there's nothing wrong with it but I was disappointed because I chose electrical over computer science in the hope of...

I have seen on several books that the expression for the E field generated by an accelerated charge, at enough distance and in the non-relativistic aproximation, is something like that (taken from Jackson): where "β with the dot above" is the acceleration divided by c, n is a vector...

Hello all, I am in need of understanding of magnetic fields. More specifically i was wondering exactly why there is a magnetic field around a wire with current moving through it. Where i am going with this is.. if i had plasma contained, and i managed to get it moving in the container, would...

Hi guys, brand-new simpleton here. Quick question: would it be possible to stop ice formation on a cold surface with an electromagnetic field? How strong should it be (if possible)? Thank you!

Hi, just reviewing some of my physics material, and realized I had a question that has never been answered for me. I know that charged particles, traveling parallel to a magnetic field, feel no force either forwards or backwards, but feel a force perpendicular that causes them to spiral...

Do the $\mathrm{SU(2)}$ gauge fields takes the same value in the Lie subalgebra spanned by the $\mathrm{SU(2)}$ field strength tensor? I will try to clarify my questions. Define the Lie algebra as: \begin{equation} [t^a,t^b] = \varepsilon_{abc}t^c \end{equation} where $\varepsilon$ is the...

Two infinite sheets of current flow parallel to the y-z plane as shown. The sheets are equally spaced from the origin by xo = 7.5 cm. Each sheet consists of an infinite array of wires with a density n = 19 wires/cm. Each wire in the left sheet carries a current I1 = 3.5 A in the negative...

I wanted to know if there is a mathematical model to know the force with which a source of a magnetic field attracts or repels another source of magnetic field. For example, the mathematical model for the electrostatic force a charged particle exerts over another charged particle is: F =...

I am reading Dummit and Foote Section 9.5 Polynomial Rings Over Fields II and need some help and guidance with the proof of Proposition 15. Proposition 15 reads as follow: Proposition 15. The maximal ideals in F[x] are the ideals (f(x)) generated by irreducible polynomials. In particular...

hello , could someone please remind me I have forgotten a few things. So the electric field is perpendicular to the conductor and the flow of charge. So if i have a pipe and in the pipe flows a conducting gas or a plasma , now around the pipe I have a simple copper wire wound in many many...

Hey. Let's say you have an infinitely wide and long disk with a thickness h. Inside the disk, there is a constant charge density ρ0. Why would the electric field lines be perpendicular to the disk? Can somebody explain how symmetry and such generally affect electric field distribution of a...

edit: Nevermind, I found the answer myself :X

Homework Statement Two point charges are placed at the opposite corners of a rectangle as shown. What is the Electrical Field magnitude at each point due to the charges?Homework Equations Pythagorean theorem, E=kq/r^2The Attempt at a Solution r= square root of .8^2 +.4^2 =.89 E= 8.99x10^9 X...

How is it that the electric and magnetic fields in unpolarized light are not canceled out? The simplest example would be two photons of the same energy traveling coherently in time along exactly the same path in space, differing only by a rotation of 180 degrees around the axis of travel...

Hey guys, just got a question at school and the last part makes no sense. I replicated it almost exactly, except for the diagram. Just imagine the dotted line is a solid line indicating the electric field lines. Ignore the 4 dots around X, it was just to keep the field lines in line.Question 4...

I've seen different objects described as the field in GR: the metric, the connection (and then the metric is seen as the "potential" by analogy with EM field theory), both... Could someone comment on what object should most reasonably be considered the field of the GR theory? Could for...

correct me if I am wrong but there are fundamental fields that are responsible for the forces and properties. A) how do these fields (em, higgs ect.) influence matter? B) where did they come from and when? Thanks

Hello everyone, I'm a photographer and am developing a project in which I'm needing some help. I went to some engineers friends first but they told me Physicians would be the ones who would have the answers I need. I'd like to know how can I interfere in the way my camera's sensor...

Homework Statement The Lie bracket of the fundamental vector fields of two Lie algebra elements is the fundamental vector field of the Lie bracket of the two elements: [\sigma(X),\sigma(Y)]=\sigma([X,Y]) Homework Equations Let \mathcal{G} a Lie algebra, the fundamental vector field of an...

Where can I find a picture of the magnetic field lines produced by a charged particle moving near the speed of light? Is there a formula for the strength of B and direction of field lines as v --> c? Does this equation reduce to Ampere's right hand rule for a moving charge's ability to create...

Hi All, Just wanted to know, is there any experimental or observational evidence today, that electromagnetic fields can cause spacetime curvature? Either direct or indirect?

Homework Statement 1. If the electric field is zero at a point, the potential must also be zero at that point 2. If the electric potential is zero in some region of space, then the electric field must also be zero in that region. 3. If the electric field is zero in some region of...

Studying conformal field theory, I tried to derive general expression for the commutation relations of the modes of two chiral quasi-primary fields. At first, I expressed the modes \phi_{(i)m} and \phi_{(j)n} as contour integrals over each fields, and took commutation relation. I used...

Homework Statement A 1.0 m piece of wire is coiled into 200 loops and attached to a voltage source as shown. A. Find the strength of the magnetic field inside the coil if V = 100 V and R = 40 Ω. B. Which direction does the magnetic field point? C. The wire is then uncoiled and re-wrapped so...

Dear all, I don't understand why the Cosmic Microwave Background's angular distribution is considered to to a Gaussian random field initially. The rest of the analysis is roughly clear to me, COBE/WMAP/PLANCK measure the CMB Photons and show the temperature fluctuations w.r.t. the mean...

Homework Statement Let S = {(a, b): a, b \in \mathbb{Z} and b ≠ 0}. An equivalence relation "~" on S is defined by (a, b) ~ (c, d) iff ad = bc. 1) For any b \in \mathbb{Z} \setminus {0}, show that [0/b] = [0/1] and [b/b] = [1/1]. 2) For any a, b \in \mathbb{Z} with b ≠ 0, show that...

Hello, people: I've been wondering about the definition of Quantum Fields in Curved Space-times (CS). I know that, in flat space-time (Minkowski), the fields are defined as irreducible representations of the universal covering group SU(2)xSU(2) of SO(4) (which is basically the Lorentz group...

A negative particle is moving in a uniform magnetic field pointing in the negative k direction. The force on the particle is -i and j. Find the x and y components of velocity. (I left out the numerical data in the question). I used F=q*v*B and in order to find the x component I used the F in the...

Would a magnetic field have any effect on the dielectric breakdown of insulators? For example, the dielectric breakdown of air is 3 Mega volts per meter at a gap of one meter; if you applied a magnetic field to that breakdown, would it help guide the electrons along the path and therefore reduce...

Hello, I have a question regarding the expansion of the Kahler potential in visible sector fields C^{\alpha} : It is usually said that the Kahler potential can be expanded as follows: K = K_{hid}(\phi,\phi^*) + K_{\bar{\alpha} \beta}(\phi,\phi^*) C^{*\bar{\alpha}} C^{\beta} + \frac{1}{2}...

Homework Statement Is it possible to create an electrostatic field E(x) (in 3 spatial dimensions x and E is a vector of course) such that i) E(x) = a × x (cross product) ii) E(x) = (a.x) b (dot product between a and x) where a,b and non-zero vectors that do not depend on time and the...

Does anybody (Jester?) know how to get WolframAlpha to plot slope fields to, say, $y'=f(x,y)$? For example, $y'=x^{2}$, and I want the slope field plotted up with $x\in[-2,2]$ and $y\in[-2,2]$. What would the actual command be? Thanks in advance!

I am seeking to understand Rings of Fractions and Fields of Fractions - and hence am reading Dummit and Foote Section 7.5 Exercise 3 in Section 7.5 reads as follows: Let F be a field. Prove the F contains a unique smallest subfield F_0 and that F_0 is isomorphic to either \mathbb{Q}...

Homework Statement Heres the question: http://imgur.com/aFJFxLa Homework Equations B = μ0/2∏r The Attempt at a Solution μ0 = 4∏*10^-7 Magnetic field = μ0/2∏r + μ0/2∏r = μ0/2∏(0.05) + μ0/2∏(0.05) = 4*10^-5 The answer is 24*10^-6 T. I need...

Homework Statement Homework Equations The Attempt at a Solution I used ∇ X F for part (a) and part (b) and found both to be ≠ 0. Thus both cases F is not conservative. I have no clue about the second part, as both arent conservative...

Homework Statement Heres the probelm: http://imgur.com/TbzJxVa Homework Equations e = kq/r^2 The Attempt at a Solution q-p Ex = (9*10^9)(4)/(0.80)^2 = 5.625*10^10 Q-p E1 = (9*10^9)(6)/(1)^2 = 5.4*10^10 Ex = E1sin45 = -3.82*10^10 Ey = E1cos45 = 3.82*10^10 P p =...

I am reading Dummit and Foote Section 9.2: Polynomial Rings Over Fields I I am having some trouble understanding Example 3 on page 300 (see attached) My problem is mainly with understanding the notation and terminology. The start of Example 3 reads as follows. "If p is a prime, the ring...

calculating electric fields due to continuous charge distributions? a question I came across doing some electric field questions, and the answer was really confusing. Homework Statement Charge is distributed along a linear semicircular rod with a linear charge density λ as in picture...

Homework Statement 1) Show that ##\underline{a} = \underline{r} f(r)## is conservative and deduce a functional form for the potential if ##f(r) = r^n##. For what value of n does the potential diverge at both ##\underline{r_o} = 0## and ##\infty##? The Attempt at a Solution I have found...

Greeting PF’rs Subject: Levitation using directed electric fields If someone had a way to take a spherical mass and pump electrons into the mass and fill many of the valence electron shells in the atoms, there would be an enormous electric field emitted by the charged mass. (Yellow sphere in...

1. Homework Statement [/b] A solid cylindrical conducting shell of inner radius a = 4.9 cm and outer radius b = 6.1 cm has its axis aligned with the z-axis as shown. It carries a uniformly distributed current I2 = 7.4 A in the positive z-direction. An inifinte conducting wire is located along...

Can unquantized fields be considered smooth curved abstract manifolds? Say free particle solutions of the Dirac equation or the Klein Gordon equation? Can quantized fields also be considered curved abstract manifolds? Thanks for any help!

Say Alice gives Bob the wave-function, a momentum eigenstate, of a charged particle. Bob then makes a local gauge transformation on the wave-function, ψ --> exp[iqθ(X,t)]ψ. Can Alice now undo the local gauge transformation with the right addition (or subtraction?) of electromagnetic...

Homework Statement A current of constant density, J0, flows through a very long cylindrical conducting shell with inner radius a and outer radius b. What is the magnetic field in the regions r < a, a < r < b, and r > b? (Use any variable or symbol stated above along with the following as...

For a magnetic fields lab I am asked to graph the data and from there, use the slope to find a certain value. For one of them, I am asked to plot the current (x) vs the magnetic field (y). The slope is supposed to give me a value, I have the slope, no clue what the value would represent...

Homework Statement Two infinite sheets of current flow parallel to the y-z plane as shown. The sheets are equally spaced from the origin by xo = 4.2 cm. Each sheet consists of an infinite array of wires with a density n = 16 wires/cm. Each wire in the left sheet carries a current I1 = 2.3 A in...

Is it possible for a spherically symmetric field, on all of R^3, to have a divergence of 0? (assuming the field is nonzero) Relevant equation: F=f(ρ)a (a is a unit vector of <x,y,z>) and f(ρ) is scalar fxn, and ρ = lal

Let $K=\mathbb{Q}[\omega]$ where $\omega^2+\omega+1=0$ and let $R$ be the polynomial ring $K[x]$. Let $L$ be the field $K(x)[y]$ where $y$ satisfies $y^3=1+x^2$.Which is the integral closure of $R$ in $L$, why?

Hey Pf.. I am trying to understand Lenz's law, but somehow it doesn't make sense. In my book there is some checkpoints execise to test wheather you've understood what you read about, one those checkpoints looks like this. http://snag.gy/NCNLh.jpg I do understand why the current in...

Author: Roger Harrington Title: Time-Harmonic Electromagnetic Fields (IEEE Press Series on Electromagnetic Wave Theory) Amazon Link: https://www.amazon.com/dp/047120806X/?tag=pfamazon01-20 Prerequisities: Undergraduate degree in Electrical Engineering or Physics, with appropriate...