Flux Definition and 1000 Threads

Apparently, that's how a lot of car speedometers work... but I don't understand how a rotating magnet inside a coil (or any conductive material, really) can induce a current in the coil. I can understand how pushing a magnet in and out through a coil can induce current, because Flux = Area...

Im revising for my A levels and I could really do with a simple, straight forward definition for magnetic flux and magnetic flux density. Can anyone please help? I'd be very grateful. F=BIl ∅=BA

Homework Statement Given a vector field \textbf{F} and a composite (with this I mean cuboids, cylinders, etc. and not spheres for example) surface S, how do I calculate the flux through only some of the sides of S? I am interested in a general way to do this, but right now I am struggling with...

While I do see how this makes sense using Newton’s Shell method, I don’t see how Gauss’ Law of Flux for a closed surface proves the same thing. Both Gauss’ Law of Flux and Newton’s Shell method make perfect sense to me in showing that when dealing with a point outside the hollow conducting...

This is always zero, right? What if you construct a closed surface which only encompasses one of the poles of a magnet? Surely there would then be a non-zero flux as the inside of the surface would constitute a source (or sink) of magnetic field lines. I'm new to electromagnetism, so any...

Hi! I'm stuck on a problem concerning the magnetic field produced by a long straight conductor: A triangular piece of conductor (N=1) rests in the vicinity of a long straight conductor with a current I=50A. What is the magnetic flux through the triangle if a=1cm? (See attached file). My...

Calculate the flux, due to a point charge of 100 nC at the origin, that penetrates a sphere of radius 0.01 m centred at the origin. Would anyone know which equation I should be using for this problem? Thank you.

Find the flux of F= <XY,YZ,XZ> across the surface S of the cube {lXl≤1, lYl≤1,lZl≤1} using the given definition of flux. The first part of this problem asked me to solve using the diveregence theorem, which I did with a result of 0. I've been racking my brain on this part, seems the trickiest...

1. Homework Statement [/b] If the magnetic flux linking all the turns of a 50 turn coil changes from 10mWb to 20mWb and induces an emf of 62.5V in the coil, calculate the time over which the flux changes. Homework Equations e=Nd x change in flux / dt The Attempt at a Solution Not...

Homework Statement Vector field F = (2siny-cosz, 2cosx+3sinz, cosy-2sinx) Compute the flux of F through a sphere of radius one centered at the origin with respect to the outer unit normal. Homework Equations Divergence theorem/Gauss's Law The Attempt at a Solution The only...

Homework Statement Find the upward flux of F = <x + z, y + z, 5 - x - y>, through the surface of the plane 4x + 2y + z = 8 in the first octant.Homework Equations ∫∫(-P(∂f/∂x) - Q(∂f/∂y) + R)dA where the vector F(x,y) = <P, Q, R>, dA = dxdy and where z = f(x,y) <-- f(x,y) is the function that...

(On phone typing this, so preset subheadings haven't shown) My first question asks me to use the Poynting vector, N, to calculate the average flux of radiation, knowing that the electric field of sunlight arriving at the surface of the Earth is 500Vm^-1 I use that the average flux of...

Homework Statement In the figure, a flexible square loop 0.700 m on a side is made of wire of resistance 0.600 Ω. A magnetic field with magnitude 1.70 T is directed onto the plane of the loop. A student crushes the wires together forming a loop of zero area in 0.350 s. Find the total amount of...

Homework Statement Find the upward flux across the surface z = x of the vector field F=(y,-x,0). Homework Equations ∫∫(F\bulletn)ds The Attempt at a Solution I know what to do once I parametrize z = x but I am stuck on the parametrization. Would it just be: r(x,y) = (zi + j + xk) ?

Homework Statement Find the outward flux of F = <x + z, y + z, xy> through the surface of the paraboloid z = x^2 + y^2, 0 ≤ z ≤ 4, including its top disk. Homework Equations double integral (-P(∂f/∂x) - Q(∂f/∂y) + R)dA where the vector F(x,y) = <P, Q, R> and where z = f(x,y) <-- f(x,y) is the...

QUESTION: Compute the flux of the vector field, F , through the surface, S. F = xi+yj+zk S is the part of the surface z = x^2 + y^2 above the disc x^2 + y^2 ≤ 4 , oriented downward. I am just wondering why the integrand is from o to 4 while the radius is only 2.

Problem description: A wery long, than and flat metal plate of width 2a carries the total current I in the z-direction. The current density is uniformely distributed over the metal plate. A point P of particular interest is also shown in the figure, where the point has the position r=ax+ay...

Can anyone show me how to do this? http://img853.imageshack.us/img853/739/38647978.jpg http://img21.imageshack.us/img21/3074/62209167.jpg Calculate the flux of the field grad(f) on C.

If a loop is moved in a uniform magnetic field such that the direction of its motion is perpendicular to the magnetic field, then no change of flux occurs. Then according to faraday, no emf is induced... But I was thinking that can the emf be produced in it due to the deflection force?

Hi, When coil is excited with ac because of varying nature of current ,flux of varying nature will be developed in coil and because of varying flux emf will induce in coil. what will happen if coil is excited with dc? intially cureent will increase from zero to maximum and is...

Homework Statement See figure attached. Homework Equations The Attempt at a Solution I can follow how he applies amperes law to obtain the magnetic field produce by the wire but I'm extremely confused how he writes the expression for the flux flowing through S. What I...

I did this problem on this British Physics Olympiad paper and it assumed that when a star bigger than the sun collapses under its own gravity to create a neuron star the magnetic flux stays constant. Please explain Thanks

A single phase transformer has the following rating: 120 kVA, 2000 V/100 V, 60 Hz with 1000 primary turns. Determine: (a) the secondary turns (b) the rated primary and secondary currents (c) the maximum flux (d) given a maximum flux density of 0.25 T, the cross-sectional area of the core...

Homework Statement A ring can rotate about a horizontal axis(x), and a diameter placed on the x-axis. A uniform field is perpendicular to the ring -B0*y. The diameter of the ring is D. it spins with constant angular velocity ω around the x-axis. At at time t = 0 the ring is entirely in the xy...

Homework Statement Imagine you are trying to detect a Jupiter-like planet located 7.5E11 m from a Sun-like star. At what wavelength is the peak of the planet's Planck blackbody intensity function (assume the planet is a perfect blackbody)? Radius of Planet r = 7E7 m Radius of Star R =...

Homework Statement I am given the following problem: http://forum.allaboutcircuits.com/attachment.php?attachmentid=35938&d=1320027350 Homework Equations The Attempt at a Solution My known equations and attempt to the problem...

Homework Statement The y-axis carries a uniform linear charge density of -2 nC/m, and there is a 8 nC point charge at the point (3 cm, 0 cm, 0 cm) as well as a -4 nC point charge at the point (-8 cm, 0 cm, 0 cm). What is the electric flux through a closed spherical surface of radius 4 cm...

Hello everyone, I'm currently at third year of EPE and this software is totally new for me so i would to ask a few questions. I have been asked to use infolytica MagNet using Field Sampler tool to analyse a flux behavior in the air-gaps and in the transformer core for 2 different core...

I'm having problems understanding this solution (attached.) I don't understand how they got 2*magnetic flux out of the change in the magnetic flux in the bottom of the attachment. Can someone explain that to me?

Homework Statement A Gaussian surface in the shape of a cube has edge length 1.14 m. What are (a) the net flux through the surface and (b) the net charge (in C) enclosed by the surface if the electric field in the region is in the positive y direction and has a magnitude that is given by...

Homework Statement The electric flux through each face of a 4.50m x 4.50m x 4.50m cube is 130Nm^2/C . How much charge is inside the cube? Homework Equations Electric Flux = E*A = Qin/ε The Attempt at a Solution I know electric flux is given, 130Nm^2/C and I'm trying to solve for...

The diffusion of Ni in FCC Fe. There is 0.3 atoms % of Ni in a solid solution in FCC Fe @ point x. Point y is 1 mm away and has 0.2 atoms % of Ni within the solid solution. Temperature = 1000° C, D = 2ε-16M2/s Calculate the flux (J) between points x & y. Radius of Fe atom = 0.13 nm @...

Homework Statement Determine the electric flux through a 6m by 4m rectangular area. The area is oriented such that a vector normal to its surface points in the [1;6] direction. The electric field is [7;1] N/C. Homework Equations Φ=E·A=EA*cosθ The Attempt at a Solution...

I have two questions that I cannot seem to figure out. Homework Statement 1)A uniform electric field E=30 N/C exists parallel to the axis of a square pipe of side length l=5 cm as shown in the figure. Calculate the total electric flux for the slanted face of the pipe 2) A very long metal...

Homework Statement Basic Question. My book describes the rate of heat transfer per unit of system area as \dot{Q}=\int\dot{q}dA. The Attempt at a Solution I'm trying to solve for the flux. I've already discovered that the correct answer question is just the derivative of \dot{Q} with respect...

1. The electric field in the region of space shown is given by E=(8i + 2yj) N/C where y is in m. A) What is the magnitude of the electric flux through each face of the cube. (3.0 M sides, 2.0m from yz axis)? B) Is there any charge in the cube? 2. E * da 3. To be honest I have...

I'm currently studying Classical Electrodynamics, and I see everywhere that the flux of a field through a surface is defined as the normal component of the field times the surface area. They interpret this in a physical way as the net charge flowing through the surface in the unit of time. My...

Homework Statement An uncharged nonconductive hollow sphere of radius 19.0 cm surrounds a 20.0 µC charge located at the origin of a cartesian coordinate system. A drill with a radius of 1.00 mm is aligned along the z axis, and a hole is drilled in the sphere. Calculate the electric flux...

Homework Statement Let's say you have a solid cylinder. It is nonconducting. It is long enough such that the contributions from the ends are negligible. It has a non-uniform volume charge density of Ar^2, where A is some positive constant. Then you are asked to find the electric field at...

In general I just wanted to see if I was setting this problem up correctly. We have a cube centered around the origin and a point charge at the origin. The task is to find the flux & confirm Gauss' Law. We are however to complete the integral ourselves. So imagining the top of the cube...

hey I am calculating energy of a blackbody emitter, and i have the flux (energy per unit area) and the peak wavelength emitted. how do i calculate total energy?

Homework Statement An E-field is given as \vec{E}y = b\sqrt{y}\hat{j} V/m. Find the net flux through a cube with vertex at (0, a, 0) and side lengths a. (A picture is attached, but it is essentially the cube that would typically be at the origin, shifted along the y-axis by a units) (You can...

Homework Statement A point charge of 20 nC is located at (4,-1,-3), and a uniform line charge of -25nC/m lies along the intersection of the planes x=-4 and z=6. (a) Calculate D at (3,1,0). (b) How much electric flux leaves the surface of a sphere of radius 5, centered at the origin? (C) Repeat...

Homework Statement The total electric flux from a cubical box 40.0 cm on a side is 4700 Nm^2/C. What charge is enclosed by the box? Homework Equations Gauss Law: surface integral of E-field-vector * dA-vector = Q_enclosed/epsilon naught The Attempt at a Solution The reason I am...

Homework Statement Vector V = <x2yz2, xy3z> 0<=x <=a 0 <= y <= b 0<= z <= c Homework Equations \intV \bullet \hat{n}dS In our case, this amounts \int\intV(either x or y component) dot \hat{i} or \hat{j} dA. The Attempt at a Solution Okay, I have tried to break apart the...

Homework Statement A coaxial transmission line has an inner conducting cylinder of radius a and an outer conducting cylinder of radius c. Charge ql per unit length is uniformly distributed over the inner conductor and -ql over the outer. If dielectric \epsilon_{1} extends from r=a to r=b and...

hi, The drawing show 2 transformers T1 and T2. Each primary of transformer is at fixed voltage (110 volt for example), but one transformer is with 0° phase and other with 180° phase. The secondary of each transformer has the same charge and the same current. The idea is to cancel the flux from...

Homework Statement The Electric field E produced by an unknown charge distribution p (rho) is E(r)= (constant)*((exp(-ar))/r^2)*(r_hat). a.) Use Gauss' law in differential for to determine p(rho) b.) Find the total charge q_tot by directly integrating p(rho), and show that it is 0. c.)...

Homework Statement A point charge q1 is located on the y-axis at r1= a (Y_hat) and another q2 located at the mirror point r2= -a (Y_hat). The charges are not necessarily the same sign or magnitude. Now consider the circular surface S of radius a contained in the x-z plane through the origin...

Homework Statement A cube of edge length 0.05m is positioned as shown in the figure below. A uniform magnetic field given by B = (5 i + 3 j + 2 k) T exists throughout the region. a) Calculate the flux through the shaded face. Homework Equations \phi = B.A cos \theta The Attempt at a...