Flux Definition and 1000 Threads

**I need Help calculating Electric Flux? Homework Statement "A 2.51 μC point charge is placed at the center of a cube with a volume of 7.27 m3. Calculate the electric flux through one side of the cube." Homework Equations Eflux = E*Surface Area The Attempt at a Solution I tried...

Homework Statement An infinite slab of uniform charge density ρ occupies the region -∞<x< ∞, -∞<y<∞, -d/2<z<d/2. Homework Equations Use Gauss' Law to calculate the electric field density for -∞<z<∞ The Attempt at a Solution D=εE. Using that, I just need to find D =...

This is a question that has kept me awake, trying to rationalise it: Current is rate-of-change-of-flux (or charge if you prefer, which is the same thing): i = dQ/dt Therefore, flux or charge is the time integral of the current. Q = ∫i dt Therefore, if you have a direct current, does...

The flux rule for motional emf can be stated as: d\phi/dt = -\epsilon I have some questions regarding this. 1) Should I find this rule intuitive? And secondly a proof of this rule is given in my book, which I have attached. I don't really understand the idea of the proof - is the idea to...

Homework Statement Homework Equations \phi = \vec{E} * A * d phi is the electric flux E is the Electric field from vector form A is the area and A = \pir^{2} d is the distance on the axis (x, y, or z) The Attempt at a Solution s1 = s3 = 0 *Since they are along the y-axis...

Homework Statement Let F(x,y) = ( P(x,y), Q(x,y)) be a vector field that is continuously differentiable along the closed smooth curve C : x2+y2 = 1. Moreover let -F(x,y) = F( -x, -y)≠ 0 and P(x,y) = -P(-x,y) and Q(x,y) = Q(-x,y). Determine all the possible values of the circulation...

I have constructed a formula to represent the neutron flux from a disc emitter through an aperture. I have got it down to a double integral of a form that I can't see how to evaluate. Mathematica crashes on this and I am not ready yet to give up and go to numerical solution. Does anyone know a...

"Flux in Through/ Out of Caps" Purcell Homework Statement I'm working problem 5.11 in Purcell's E&M book. It's about relativistic particles, and the eventual condition about angles at which the E-field lines are directed. The ultimate goal is to prove that tan(\varphi)=\gammatan(\theta)...

Is there a simple way of calculating photon flux density from the lumens produced by a fluorescent tube?

Homework Statement A 10 cm long, 1 cm diameter solenoid contains 500 turns of wire. A current that varies as I = 5Sin(100πt) Amps flows through the solenoid wire. Calculate the magnitude of the magnetic flux at the centre of the solenoid as a function of time using equation (1). Compare this...

Homework Statement The relationship between the current in an N-turn coil and the flux created by it is given as: \Phi = \frac{ai}{b+ci} Determine the energy stored in the coil when the current varies from 0 to I. Homework Equations W = N \int{i d\Phi} The Attempt at a...

Homework Statement Find the flux of the following fields: F_1 = xi + yj F_2 = -yi + xj across the following curve: The circle r(t) = (cost) i + (sint) j t is from [0,2pi] Homework Equations Flux = ∫F dot n ds = ∫M dy - N dx The Attempt at a Solution For F_1 I got: M = x =...

Homework Statement The monochromatic flux emitted from unit surface area of a black body is given by F_{\lambda}(T) = \frac{2h\pi c^{2}}{\lambda^{5}} \frac{1}{exp(hc/\lambda KT)-1} Wm^{-2}m^{-1} If the distance to star X is 620 parsecs, calculate: (a) the radius of star X, in...

Homework Statement A solenoid has a radius of 2mm and a length of 1.2cm. If the # of turns per unit length is 200 and the current is 12A, calculate the magnetic flux density at a) the center and b) the ends of the solenoid Homework Equations The biot-savart law: \vec{B} = \frac{\mu_0}{4...

Homework Statement As shown in the figure below, potential difference V exists between two parallel plates(a,b) that have a small hole. Uniform electric field E and magnetic flux density B exist in the region above the plates, and are perpendicular to each other. The directionof E is parallel...

Hi, I'm facing a real-life problem and I don't what specific mathematics topic it's related to. Homework Statement I know the value of the components of a vector field in three points of space and I have to find the flux of this vector field through the surface defined by those...

From what I learned, for an electric current to be induced in a wire, there must be a magnetic flux. On youtube, there are lots of videos showing wireless power transfer to a lightbulb or LED. However, the light is constant. How is the magnetic flux changing in such a setup?

This is my first post here. I have a problem dealing with Electric flux. According to Gauss's Law, to find electric flux we use equation: ψ=∫D dot dA, both D(Electric flux density) and dA(super small area normal to the surface) are vector quantity. Now this is what I confused, how...

Hi, so this is my first time on this forum and I've just gotten very frustrated with trying to understand this one problem. I got part A by using divergence theorem but I don't know how go about computing part B. Suppose F⃗ (x,y,z)=⟨x,y,5z⟩. Let W be the solid bounded by the paraboloid...

I need help regarding a practical problem I'm facing. It's not a homework/coursework, It's a real-life problem. I have the values of a vector field (wind) given in six coordinates in 3D space. Those coordinates are the vertices of a triangular right prism (looks similar to my problem...

Homework Statement A uniform electric field with a magnitude of 600 N/C is shown pointing in the y-z plane, at 30 degrees from the +y axis and at 60 degrees from the +z axis. This electric field passes through a cube, with each side of length 2.0cm and oriented with faces in the +x, +y, and +z...

Hello all, long time follower, first time poster. (Also feel free to move this if it's not in the right section.) Basically I have this mechanism pictured here: You can imagine that the drawing is of a top view of a section cut of the total mechanism. This is the radius view, the full diameter...

Which Gaussian surfaces have an electric flux of +q/εo through them? I think is b since in c, +q and -q cancel each other out, d is only -q is that the right approach? thanks!

Homework Statement I know I posted a question yesterday also, but this homework is getting on my nerves. My prof isn't the best out there. So basically the question is as follows: http://img812.imageshack.us/img812/8130/problem6.png Homework Equations Not sure, I sort of answered the...

Hey everyone. I've been working on a axial flux permanent magnet DC generator to use on a 100W wind turbine(small I know), to charge 12v batteries in low wind speed areas. Now that it's complete, I'd like to determine the full power curve at different rpms. So far I've been running it on NO...

I know that when there's a magnet next to a piece of iron, the former's flux density just travels across the air gap between them provided it's small enough. But what happens when there's two magnets next to each other? I know B follows the superposition principle, so do their flux densities...

What is "Magnetic flux quanta"? is there any animation describing this subject?

I'm actually a teacher and I can't explain this problem from the 2007 HSC. I've attached a copy of the question and the two graphs. The question shows a graph of change in magnetic flux vs time and asks you to choose which graph of induced emf best fits it. I don't understand why the induced emf...

[EDITED] Why is the electric flux through a closed surface zero? My book based the reasoning from a uniform electric field. I understand that for a uniform electric field, the electric field doesn't diminish in magnitude as we move away from the source, and if we construct a box-shaped closed...

Hi all, I want to learn tools like MAXWELL 2d 3d , MAGNET, FLUX etc. I want to know if I'll need to know CAD and FEM Analysis to learn the above mentioned tools. Thankyou, Chaitanya

If an aluminium disk is placed above a COMPLETELY vertical current carrying iron rod will any flux link with the aluminium disk... Firstly, does it matter if the current is AC or DC. I presumed not as the only difference is that the magnetic field will vary in one case and stay constant in...

What is measured in a fast reactor for power calculation : fast neutron flux or overall ( fast + thermal) neutron flux ? My doubt is : The fission chambers used for measuring neutron flux undergo chemical reactions due to which type of neutron : fast or thermal ?

Homework Statement Vector field ##\vec F= 4x \hat i+4y \hat j +3 \hat k## Let S be the open surface above the xy-plane defined by ##z=4-x^2-y^2## a. Evaluate normal outward flux of F through S. b. Use Stokes' theorem to evaluate the normal outward flux of ##∇ \times \vec F## through S. c...

Homework Statement Please let me know whether it's wrong for my attached solution. Homework Equations i = (d∅/dt)/R The Attempt at a Solution In part (d), does it calculate wrong?? In part (e), where has the dissipated energy? is it for heat energy?? Thanks!

Homework Statement Please let me know whether it's wrong for my attached solution. Homework Equations magnetic flux = BAcosθ The Attempt at a Solution I don't know how to calculate the part (c) as attached file, please advise!

I have read that when the secondary of a transformer has current flow, it will reduce the magnetic flux in the core. This then reduces the back-emf on the primary, causing a increase in current to reestablish the magnetic flux to what it once was. What I want to know is when the secondary...

I have deposition rate of Silicon dioxide as 1000A/minute. I need to calculate molecular flux to the surface. First I tried to use ideal gas theory but since SiO2 is not ideal gas therefore my answer was completely wrong. I am disoriented. Can anybody help. I know the answer is 3.8E15...

Suppose I have a plasma. Inside the plasma is a knotted flux tube in an electric field. Will it tend to move? Is this there a better forum for this question?

Homework Statement Compute the flux of the vector field F(x,y,z)=(z,y,x) across the unit sphere x2+y2+z2=1 Homework Equations I believe the forumla is ∫∫D F(I(u,v))*n dudv I do not know how to do the parameterization of the sphere and then I keep getting messed up with the normal vector.*...

Homework Statement This is more of a general question about magnetic flux in a uniform magnetic field, but I think this is the correct place to post it. I understand that magnetic flux through an area A is the product of the magnetic flux density B and the projection of area A onto a surface...

If B~1/r2, then if we have a simple loop, B near the inner edge of the loop will be infinite (or close to it). Why then, would our flux not be infinite? I also get infinity if I take ∫ ∇ X A *da =∫B*da =∫(closed)A*dl Since A ~1/r and r~0 at the limit of our surface integral. I know I am...

Homework Statement A simple loop of 5 cm radius encompasses the middle turns of a long coil. The coil has 2500-turns, is of length 1 m and radius 1 cm, and carries a current of 10 Amps. What is the magnetic flux through the single loop? Homework Equations B=μIN/L with L=1: B=μIN...

Homework Statement A point charge Q is placed at the center of a cube of side L . What is the flux through one face of the cube? Express your answer in terms of some or all of the variables Q ,L and appropriate constants. The Attempt at a Solution I'm getting Q/6e0 , is this...

Homework Statement A 200-loop coil of cross sectional area 8.5 cm2 lies in the plane of the page. An external magnetic field of 0.060 T is directed out of the plane of the page. The external field decreases to 0.020 T in 12 milliseconds. What is the magnitude of the change in the external...

Homework Statement A wire loop with radius R is located a distance d from a long straight wire carrying a current I. Find the flux through the loop. Homework Equations B = \muI/(4\pi) Magnetic Field above wire \phi=B*da*cos\vartheta The Attempt at a Solution Somehow you have to...

I have attached a file with my question. From what i see the flux for both surfaces will be 0. I am unsure and need a little of explaining

Homework Statement The velocity of a fluid is given, in cartesian coordinates (x, y, z), by \vec{v} = v_{0}x\hat{z} being a constant with velocity dimensions. a) Calculate the flux of this vector through the closed surface composed by z-x²-y²=0 and by the plan z=8 limited by the circle with...

What would happen if a magnetic field is generated inside of a Type II superconductor? Would there be flux tubes?

Homework Statement Calculate the flux of vector field F = -3r through sphere radius 5 at the origin. Homework Equations The Attempt at a Solution Since the orientation is always exactly opposite of the orientation of the surface, I expect a negative answer. Also, since they...

So we recently began electrostatics and here you encounter Gauss' law saying that the flux integral of an electric field E over a closed surface is only dependent on the charge confined within the surface. Now for a sphere that's pretty obvious why. Because since the field gets weaker...