Flux Definition and 1000 Threads

Homework Statement The magnetic flux density in the vicinity of a large air-cored electromagnet is determined by measuring the induced flow of charge in a small coil as the current in the electromagnet is switched on -- see the diagram below. Calculate the magnetic flux density at the...

Homework Statement Two identical wires R and S lie parallel in a horizontal plane, their axes being 0.10 m apart. A current of 10 A flows in R in the opposite direction to a current of 30 A in S. Neglecting the effect of the Earth's magnetic flux density calculate the magnitude and state the...

Homework Statement A long air-cored solenoid has two windings wound on top of each other. Each has N turns per metre and resistance R. Deduce expressions for the flux density at the centre of the selenoid when the windings are connected (a) in series, and (b) in parallel, to a battery of EMF E...

Since reluctance is equal to length decided by product of permeability and area of cross section,how does reluctance change with flux?

Homework Statement A circle, centered on the origin, has a radius of 1 mm. At each "pole" (1,0), (0,-1), (-1,0), (0,1) is an electric dipole. The positive charge of +10 microCoulombs is inside the circle, the negative charge of -10 microCoulombs is just outside the circle. What is the...

Homework Statement A long wire (X) carrying a current of 30 A is placed parallel to, and 3.0 cm away from, a similar wire (Y) carrying a current of 6.0 A. What is the flux density midway between the wires: (a) when the currents are in the same direction, (b) when they are in opposite...

I remember reading that in addition to the ITER, that they're also building a facility to study the intense neutron flux that is expected from the reactor in order to study how to better protect materials from the flux. Anyone remember the name of the facility? I'm having trouble finding it.

Homework Statement Here is a picture of the problem https://www.dropbox.com/s/2bps6ga2o4hjpgw/hw4.png?dl=0 For those who don't want to click the link, basically the problem wants me to calculate the surface brightness of a flat surface at any angle if the source function S = B(T), which is a...

i was going through Gauss law and the chapter started with flux of a vector field.i understand it mathematically but not physically, i have been reading on the net and most common explanation is that it is the amt of "something"(anything) crossing a given surface.fine till here.then i read that...

Homework Statement I need help in figuring out if I have done this problem correctly. From what I understand ∫E * dA = E*A, where E is the electric field and A is the area of a side. My biggest concern is if I can plug in the length "L" for the "x" and "z" variables within "E = -5x * E0/L i +...

There are 2 primary flux paths in a permanent magnet brushless DC motor. One from the north face of a magnet to the stator through the coils/windings then into the south pole of the adjacent magnet. The other flux path would be from the backside of the magnets through the rotor metal they are...

Homework Statement The figure below shows a closed loop of wire that consists of a pair of equal semicircles, of radius 7.0 cm, lying in mutually perpendicular planes. The loop was formed by folding a flat circular loop along a diameter until the two halves became perpendicular to each other...

Homework Statement In a cubical volume, 1.05 m on a side, the electric field is given by the formula below, where E0 = 1.25 N/C and a = 1.05 m. = E0(1 + z/a) i + E0(z/a) j The cube has its sides parallel to the coordinate axes, see the figure. Determine the net charge within the cube...

Homework Statement Calculate the net flux (moles m^2- s^-1) of glucose molecules across a distance of 1um if the concentration difference is 100 mols m^3- and the diffusion coefficient for water is 5x10^-10 m^2 s^-1 Homework Equations so i used J=D(c1-c2)/DelaX The Attempt at a Solution I...

Given an initial mass of some isotope subjected to a constant neutron flux, how fast will the mass drop off? Would not the survival curve look exactly like the curve for radioactive decay? Both cases describe a starting mass subjected to a constant transformative force at a rate that depends...

Why do axisymmetric FEA models of magnets and their fields make the field farther from the axis appear denser than it really is when the flux line mode is enabled? I'm using the F.E.M.M. system at the moment. All integrals and graphs give correct values, but the depicted lines of flux appear...

Hey all, first time posting! So I'm having trouble with understanding the differences between the constant heat flux and constant temperature condition when not in a textbook. Some research I have begun working on involves a strip of heat tape sandwiched between two aluminum plates which are...

Hi to all. I am simulating a "core less axial flux PMG". This PMG has significant cogging torque. I don't know where this torque comes from because this is a core less generator therefor there is no slot in stator ( no reluctance variation).

Homework Statement Hello, A 3.60cm x 4.50cm rectangle lies in the xy-plane. What is the electric flux through the rectangle if E=(80.0i + 50k) N/C ?Homework Equations Φ = E * A =EAcos(θ) The Attempt at a Solution My attempt: First convert the rectangle units from cm to m. 4.50cm = 0.045m...

Hello, The problem: A 3.60cm x 4.50cm rectangle lies in the xy-plane. What is the electric flux through the rectangle if E=(80.0i + 50k) N/C ? My attempt: First convert the rectangle units from cm to m. 4.50cm = 0.045m 3.60cm = 0.036m Find the area of the rectangle. A = 0.036m x 0.045m =...

When we record the flux of a light coming to us from outer space, which light do we use? Do we use visible light or X-ray or UV? Or is it all? Or does it depend on what we're looking at?

Homework Statement Consider an electric field E = 2x i - 3y j. The coordinate x and y are measured in meters and the electric field is in N/C. What is the magnitude of the flux of this field through a square whose corners are located at (x,y,z) = (0,2,0), (2,2,0), (2,2,2), (0,2,2)? Homework...

The stars in our Galaxy have luminosities ranging from $L_{\text{min}}$ to $L_{\text{max}}$. Suppose that the number of stars per unit volume with luminosities in the range of $L$, $L+dL$ is $n(L)dL$. The total number of stars per unit volume if clearly $$n = \int_{L_{min}}^{L_{max}} n(L)dL.$$...

For a standard solenoid, I've found that B=μnI where μ = permeability of the core (4π×10^-7 for free space) n = number of coils I = current Firstly, is the permeability of soft iron 0.08, as I found? Primarily, however, I'm wanting to know if this still applies for a mutual induction apparatus...

The video:

Does a magnet have to penetrate the plane of a coil in order to generate an emf in the coil? Would an emf be obtained if the coil only passes through the magnetic lines of force, without the magnet crossing the plane of the coil? Thank you.

As most of know that magnetic field arises due to change in electric field flux over a surface. In the same way, is there any kind of field arising due to gravitational field flux about a surface ? And if yes then does gravitational field and that field cause each other (in the same way electric...

how is flux scalar if the magnetic field and area both are vector quantities?

When a supercooled type two superconductor is subjected to a static magnetic field, the superconductor pins to the flux of the field (the mixed-state meissner effect is apparent). What happens if it is subjected to a continuously changing magnetic field, assuming the superconductivity takes...

Homework Statement A cube side length a=2 has one vertice at the origin of the referencial. an electric field is present described as follows: E(x,y,z)= (2xz) i + (x+2) j + (y(z^2-3) k Find the flux through the cube My cube's front face is at (0 to 2, 0, 0 to 2) Homework Equations flux=∫E.dA...

Homework Statement Does the magnetic flux depend on the shape of the surface or on the enclosed current? Or both or neither? Homework Equations - The Attempt at a Solution I have no clue. I guess a change in the enclosed current is a change in the field and thus a change in the flux, but I...

In a smoke detector there is 1 muCi of Am-241. I'm assuming that means it emits (3.7x10^10)*(1x10^-6)=3.7x10^4 alpha particles per second. Each alpha particle has a charge of 2e, so it seems to me that this stream of particles leaving the Am-241 pellet would carry a current of...

I am trying to calculate the flux density of an air gap in an electromagnet. I am following this page that calculates the flux density in a C core with an air gap. My confusion is that I am using 50Hz AC instead of DC I have control over the voltage amplitude since I would be using a variac to...

Homework Statement Two hemispherical surfaces, 1 and 2, of respective radii r1 and r2, are centered at a point charge and are facing each other so that their edges define an annular ring (surface 3), as shown. Homework Equations The field at position r⃗ due to the point charge is: E⃗ (r⃗...

Homework Statement Evaluate ##\int\int_S \textbf{F}\cdot\textbf{n} dS ## where ##\textbf{F}=(z^2-x)\textbf{i}-xy\textbf{j}+3z\textbf{k}## and S is the surface region bounded by ##z = 4-y^2, x=0, x=3## and the x-y plane with ##\textbf{n}## directed outward to S. The attempt at a solution I've...

this might have been answer before. Question is, what in physics or chemistry creates a load on a generator when the demand increases. For example, If no lights are turned on connected to a generator, it will spin freely. but the more lights are turned on the harder is to spin the generator...

Homework Statement We have a fluid with density ρ which is rotating about the z-axis with angular velocity ω. Where should a unit square, call it S, be placed in the yz-plane such that there is zero net amount of fluid flowing through it? Homework Equations...

Let's say we have a coaxial cable with a 2d rectangular surface lying between the inner and outer conductors and running the length of the cable. I'm trying to understand why the magnetic flux through this surface only includes the magnetic field generated by the current flowing through the...

Let's introduce a time-varying scalar field ρ(x,y,z,t) [charge density] and vector field J(x,y,z,t) [current density] Assuming the system follows Maxwell's equations, what must both fields satisfy such that ##∇⋅(\frac{∂B}{∂t})=0## ?

Homework Statement A long straight wire has a line charge, λ that varies in time according to: λ = λ0e(-βt). A square loop of dimension, a, is adjacent to the wire (at a distance a away from the wire). Calculate expressions for the displacement current at the center of the wire loop and the...

I'm not sure if I should be posting here of all places but it's worth a shot. I just had my unit test and there was a pretty weird problem on it where there was a circle of radius r in 3space on the plane of ax+by+cz=d and you were given the circle's center (C1,C2,C3). To be clear, I was given...

how is this true? I get that it's the rate of change of flux, and if you have a graph of flux linkage against time, the gradient with a constant gradient then emf is constant since it IS the gradient... But how? If the flux linkage is increasing, why doesn't the emf?

I have a liquid scintillator, the electronics system, and a beam of neutrons from a reactor. How do I calculate the neutron flux? Cold anybody give me a formula or equation? Not this equation: phi = n X v, where phi - flux, n = number of neutrons per cm3, v = velocity of the neutrons, because I...

Magnetic flux density B is a vector quantity and thus represents a force. However most texts state that the magnetic force is perpendicular to the direction of B, which is tangential to the magnetic field line at any give point. I assume that this magnetic force refers to the Lorentz force. So...

Can anyone explain in a transformer, how could a non-sinusoidal wave of exciting current produces a sinusoidal wave of flux?

So I was busy trying to imagine the ways in which lenz's Law would work physically. So I imagined a loop through which a magnet is brought and after that the magnet is pulled out of the loop a current is induced in order to keep up the magnetic field. So in this case the flux would go down which...

Homework Statement So I understand that the magnetic flux is equal to the integral of (B dotted with dA) (new to the site don't know how to use math symbols). My question is, how come in some problems, is it ok to just say the magnetic flux is equal to the magnetic field times the area, while...

Homework Statement A metal sphere of charge +6μC is surrounded by a metal shell of net charge +6μC. Which of the following diagrams represents the electric field lines of the system? Homework EquationsThe Attempt at a Solution The correct answer provided by my teacher is a figure with 12...

Homework Statement A long, straight wire has a line charge, λ, that varies in time according to: λ = λ0 exp(-βt). A square wire loop of dimension a is located adjacent to the wire at a distance of a from the wire. Calculate expressions for the displacement current at the center of the wire loop...

When we looked at some closed surface, we defined the overall electric flux of that surface as the sum of all infinitesimal fluxes of all the infinitesimal surfaces that make the quoted closed surface. Does that change if we do not have a closed surface, but a rigid body such as, let's say, a...