What is Magnetic flux: Definition and 366 Discussions

In physics, specifically electromagnetism, the magnetic flux through a surface is the surface integral of the normal component of the magnetic field B over that surface. It is usually denoted Φ or ΦB. The SI unit of magnetic flux is the weber (Wb; in derived units, volt–seconds), and the CGS unit is the maxwell. Magnetic flux is usually measured with a fluxmeter, which contains measuring coils and electronics, that evaluates the change of voltage in the measuring coils to calculate the measurement of magnetic flux.

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  1. B

    Magnetic flux through a coil. Field generated by a straight conductor.

    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...
  2. S

    Finding Charge From Changing Magnetic Flux

    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...
  3. beyondlight

    Magnetostatics. Calculate the magnetic flux density.

    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...
  4. A

    Find Magnetic Flux: Solve Triangle θ & x0 in xy Plane

    Homework Statement There is a triangle in the upper right hand corner of the xy plane. You are given θ, and x0. Consider an electric field which does not vary with time or the z direction but which varies in the x and y directions according to E=K(x2y, -xy2) throughout the region of interest...
  5. jegues

    Magnetostatics - Magnetic Flux + Force

    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...
  6. N

    Is the magnetic flux in a neuron star creation constant? Why?

    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
  7. J

    Magnetic Flux analysis in transformer design.

    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...
  8. P

    Help Me Understand: Magnetic Flux Problem Solution

    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?
  9. N

    How Do You Calculate Magnetic Flux Through a Cube's Face?

    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...
  10. L

    Discovering Gauss's Magnetic Flux Experiment for Magnetism Law

    Does anyone have any clue on how Gauss experimented on his law for magnetism? The experiment he did to find the magnetic flux Any help will be appreciated
  11. Z

    Checking Magnetic Flux Calculations: BA cos(delta) = 0.512 Weber & NBA = 9 Weber

    Homework Statement The first question I used BA cos(delta) My answer was 0.512 Weber The second question I used NBA My answer was 9 Weber I would like to know whether my answers are right thank you [PLAIN]http://img263.imageshack.us/img263/751/doentx.jpg
  12. F

    Calculate the value of magnetic flux density in air

    Homework Statement Calculate the value of magnetic flux density in air in the middle of two straight parallel wires carrying currents of 10A and 20A in the opposite directions. The distance between wires is 10cm. The Attempt at a Solution \oint \vec{B}\cdot d\vec{A} = \Phi \oint \frac{\mu_0...
  13. T

    Current produced by varying magnetic flux

    I'm translating the problem, so sorry for the errors. Homework Statement Radius of the upper circumference = 5cm Radius of the lower circumference = 9cm Resistance/meter = 3.00 ohm/meter B is the magnetic field: DB/dt = 2.00 T/s What's the magnitude of the current, and where does the...
  14. H

    How do change in magnetic flux induces emf in a coil ?

    According to Faraday's laws... change in magnetic flux linking a coil induces current in the coil.., but for conduction of electrons ...there must be an electric field ! how is the electric field induced in the coil??
  15. S

    Magnetic flux density in the centre of a current carrying loop

    Homework Statement A current carrying loop of wire is being monitored using a Hall-effect magnetic field probe placed at its centre. The loop is in air and has a radius of 0.5 m. It is required to monitor the magnetic flux in order to trip the circuit breaker if the current exceeds 100 A...
  16. S

    Exploring Magnetic Flux and Field Lines

    Homework Statement <\body> <with|mode|math|\<b-phi\><rsub|B> = <big|oint>><with|mode|math|\<b-B\> \<cdot\> \<b-d\>\<b-A\>>\ \; magnetic flux is proportional to the number of field lines passing though the surface \; </body> <\initial> <\collection>...
  17. S

    Vector potential and constant magnetic flux density

    Hi, I would like to verify analytically that a vector potential of the form A=1/2(-yB0,xB0,0) produces a constant magnetic flux density of magnitude B0 in the z direction. (I guess I'd have to use the relation B=\forall\wedgeA...)
  18. D

    Magnetic Flux through a wire loop

    Homework Statement I understand that if we have a solenoid with AC current running through it, it will create a changing magnetic flux. Suppose now we place the solenoid in the centre of the a single loop wire, according to faraday's law of induction, that single loop wire will have a...
  19. X

    Solenoid magnetic flux and emf

    Homework Statement A wire of resistance 11 ohms and length 2.3 m is bent into a circle and is concentric with a solenoid in which the magnetic flux changes from 8 T·m2 to 6 T·m2 in 0.2 seconds. a) What is the emf in the wire? b) What is the non-Coulomb electric field in the wire? c)...
  20. G

    Induced magnetic flux through a coil

    Homework Statement A circular conducting coil with N=100 turns and radius "r" is oriented in the xy plane. The leads of the coil are connected to a circuit with resistance "R." A time varying external magnetic flux density "B" is applied along the z-axis. What is the total magnetic flux...
  21. C

    Magnetic Flux Induced current

    Say I have a closed metal rectangular shaped wire in a region with a magnetic field. If the magnetic flux is constant, there is no induced current, no experienced force, and no EMF? If I start the changing the magnetic flux, I suppose by increasing the magnetic field, there will be an...
  22. H

    What is the Induced Current in a Time-Varying Magnetic Field?

    1. A current loop with a resistance R = 522 and an area A = 0.28 m2 is oriented perpendicular to a magnetic field that varies in time as sketched in the figure. What is the current induced in the loop at t = 0.30 s...
  23. H

    Induced emf is proportional to the magnetic flux

    According to the faraday's law,the induced emf is proportional to the magnetic flux change linking the conductor.However,I wonder why there is induced emf when conductor is moving in uniform magnetic field,because i think that the magnetic flux linking to it is always the same as it move in...
  24. G

    Magnetic flux against e.m.f (V)

    Hi, Could someone confirm for me please. As the magnetic flux increases does the e.m.f increase as well? (solenoid) And if we were to plot a graph of the two against each other, the graph will have a positive line/curve. My graph has a negative curve suggesting that as flux increases e.m.f...
  25. D

    Metal Magnetic Flux 9: Calculate Induced Current & Resistance

    9. Two sliding metal bars of length l = 15.0 cm are moving along two parallel rails, in opposite directions, with constant speeds of v = 0.7 m/s, as shown in the figure below. The rails are located in a uniform magnetic field with a magnitude 0.35 T that is directed into the page as shown...
  26. A

    Magnetic flux and coil of wire

    Homework Statement A coil of wire with 100 turns and a cross-sectional area of 0.1 m2 lies with its plane perpendicular to a magnetic field of magnitude 1 T . (a) Describe in your own words the meaning of magnetic flux (b) calculate the total magnetic flux passing through the coil. (c) If the...
  27. I

    What is the EMF of a coil with a changing magnetic flux?

    Homework Statement what is the emf if the magnetic flux through a coil at 50 turns is reduced from 0.5 weber to 0 weber in 0.2 seconds? Homework Equations [b]3. The Attempt at a Solution : dont even know how to get started with this problem
  28. G

    Does magnetic flux change if the area is extended past the B field?

    Homework Statement A solenoid 2.50 cm in diameter and 30.0 cm long has 300 turns and carries 12.0 A. Calculate the flux through the surface of a disk of radius 5.00 cm that is positioned perpendicular to and centered on the axis of the solenoid. Homework Equations B = (permeability...
  29. M

    Measuring Magnetic Field Intensity (H) and Magnetic Flux Density (B).

    Now here is a real world practical application. Australia Post has a warning for shipping magnetic material in the post. Section D2.9.2 states... Any material that, when packed, has a magnetic flux density of 0.159 A/m or more at a distance of 2.1 meters from any point on the surface on the...
  30. T

    Where Can I Find More Information About Magnetic Flux Twisting?

    Can someone please give me a lead where I can find more information about this phenomenon? Shrug - I guess I take point blank dismissal too... it's obviously happening, what is the phenomenon called?
  31. P

    How Is EMF Induced in Different Magnetic Fields?

    Homework Statement Figure below shows two circular regions R1 and R2 with radii r1 = 21.7 cm and r2 = 30.5 cm. In R1 there is a uniform magnetic field of magnitude B1 = 51.3 mT directed into the page, and in R2 there is a uniform magnetic field of magnitude B2 = 75.7 mT directed out of the...
  32. N

    Magnetic flux with non-uniform magnetic field

    Hi there, You know how magnetic flux through a loop of area A is the integral of B dot dA? If the area is perpendicular to the magnetic field, then we can write the dot product as B dA cos 0 = b dA. Also, if the magnetic field is uniform, the B can be brought out of the integral sign, and...
  33. R

    Calculating Magnetic Flux Density in a Solenoid

    The magnetic flux density B( in tesla ) inside the solenoid and parallel to its axis is given by the expression B= permeability of free space x n x I, where n is the number of turns per metre length of the solenoid my question is so for example, if n = 100turns in 1m and I = 2Ampere...
  34. M

    What is the total magnetic flux through the plastic of the soda bottle?

    Homework Statement An open plastic soda bottle with an opening diameter of 2.7 cm is placed on a table. A uniform 1.95-{\rm T} magnetic field directed upward and oriented 21^\circ from vertical encompasses the bottle. What is the total magnetic flux through the plastic of the soda bottle...
  35. A

    Magnetic Flux with iron filings

    Hi all this is my first post. I would like to see magnetic flux is there anyway I could do this I remember at school many years ago using iron filing. I would like to see the results of magnetic shielding
  36. L

    Solving for Magnetic Flux in a Square Loop

    Homework Statement A 3.0 magnetic field makes a 55deg angle with a square loop 25cm on a side Homework Equations MFlux = BACos(theta) The Attempt at a Solution =3*.252*cos(55) =0.11Wb Answer is to 2 sigfigs. This is a masteringphysics problem, and I'm wondering if I'm missing something...
  37. P

    Magnetic Flux in 2.6T Field & 26cm Square Loop

    Homework Statement A 2.6T magnetic field makes a 30 degree angle with a square loop 26cm on a side. Homework Equations phi=BAcos(theta) The Attempt at a Solution this should be a very simple question. phi=2.6*.26^2cos30 phi=0.15Wb mastering physics says this is wrong but I...
  38. D

    Graph of Magnetic Flux for DC Motor from 0-360

    Hey guys, just a quick question, what would a graph from 0 < x < 360 for magnetic flux look like for a DC motor, where the coils initial position is parallel to the magnetic field.
  39. M

    Magnetic fieldstrength, magnetic flux, magnetic flux density

    I have a problem understanding magnetic fieldstrength, magnetic flux, magnetic flux density. Some questions that answered may ease my understanding: Is it true that the magnetic field strength B in the core caused by a current in a wire wound on a the same torodial magnetic core is...
  40. V

    Magnetic flux of rectangular loop w/ wire

    Homework Statement Find the magnetic flux of the rectangular loop. Show that \int B x dl is independent of path by calculating \oint B x dl Homework Equations The Attempt at a Solution First step was to solve for B from the wire, I did that using Biot-Savart Law for a...
  41. S

    Normal/Tangential magnetic flux density problem

    [PLAIN]http://img232.imageshack.us/img232/7172/60746674.png Homework Statement The picture attached to this question shows a magnetic slab with μr = 50. A thin conducting film (with μr = 1) lies on top of the slab and carries a surface current of 1.0[A/mm] directed out of the page. If...
  42. D

    How to find the magnetic flux thru a bent loop with given angle

    Homework Statement A 10cm x 10cm square is bent at a 90 degree angle. A uniform 0.050T magnetic field points downward at 45 degree angle. What is the magnetic flux through the loop? http://i134.photobucket.com/albums/q113/duckman_011/Image.jpg" Homework Equations Magnetic Flux=...
  43. S

    Magnetic flux generated by a motor coil

    Hi, I am not so good with magnetic equations and I am needing some advice in how to start to calculate the magnetic flux generated by a motor coil. Finally I want to be able to calculate the magnetic flux generated with and without the iron core of each coil in the motor. I will...
  44. K

    Electromagnetic Induction and Magnetic Flux Question

    Homework Statement A loop of are 4 cm^2 has its plane parallel to the field lines of the magnetic field, B = 0.6T, as shown in the figure. The loopis pulled in the opposite direction of the field with a constant velocity of v = 6m/s Homework Equations ΦB = BAcos ε = −BLv V =...
  45. C

    Calculating Magnetic Flux Through a Loop

    Homework Statement What is the magnetic flux through the loop shown in the figure below? Homework Equations magnetic flux=ABcosANGLE The Attempt at a Solution What I did is took 2*4e2 (because the area is 400cm converted to 4m) which equals 32 then 1*4e2 which is 16...Since...
  46. L

    Calculating Magnetic Flux Density in a Hollow Cylindrical Conductor

    π²³ ∞ ° → ~ µ ρ σ τ ω ∑ … √ ∫ ≤ ≥ ± ∃ · θ φ ψ Ω α β γ δ ∂ ∆ ∇ ε λ Λ Γ ô Homework Statement An arbitrarily long hallow cylindrical electric conductor shown carries a static electric current density J=\hat{z}J0. Determine the magnetic flux density B in the hallow region of radius a. Your result...
  47. G

    Solve EMF & Magnetic Flux: Find a (s-1)

    Here is how the question is stated exactly: A circular conducting loop is held fixed in a uniform magnetic field thatt varies in time according to B(t) = B0exp(-at) where t is in s, a is in s-1 and B is the field strength in T at t=0. At t=0, the emf induced in the loop is 0.0758 V. At t=...
  48. Q

    Magnetic flux through a solenoid

    ok, the magnetic field through a single ring is n\muI , so the flux is BAcos(theta), with cos(theta)=1, flux = BA = piR2n\muI so why for the entire solenoid flux, it is now nL*the flux above? where L = length of solenoid shouldn't multiplying it with just n = number of rings be suffice...
  49. G

    Magnetic Field B Flux Through a Surface Explained

    I have been asked to explain what is meant by 'the flux of a magnetic field B through a surface' and to include the case where the field is NOT perpendicular to the plane of the surface. This seems quite simple but i just wanted to check my definition with you guys I have; The flux of a...
  50. Y

    Find k from magnetic field and magnetic flux.

    Homework Statement Hello... I got a problem I really can't figure out. I have the scenario in this link: http://www.gratisupload.dk/download/41677/" Besides that I know that there is a magnetic field that works everywhere and is along the z-axis. This field, that depends on the y-coordinate...
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