What is Flux: Definition and 1000 Discussions

Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. A flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport phenomena, flux is a vector quantity, describing the magnitude and direction of the flow of a substance or property. In vector calculus flux is a scalar quantity, defined as the surface integral of the perpendicular component of a vector field over a surface.

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  1. T

    Open circuit short circuit (test) TX flux effect

    Hi, It's been a while but from what I remember when you short circuit a transformer, electrically it's like you've series'd up the coils and shorted the magnetisation branch. And when you open circuit a side of the TX it is like the current flows through a side then through the magnetisation...
  2. EpicAll Rounder

    What is Stellar Flux and How Does it Affect Solar Wind?

    I have a little problem about Stellar Flux. I've searched google and bing for info but to no avail. Please help me understand Stellar Flux. Thanks, Epicall Rounder
  3. Hijaz Aslam

    Gauss Law of Cube in non-uniform linear Electric Field.

    Gauss's Law states that if a Gaussian Surface encloses a charge ##q_{enc}## then the electric flux through the Gaussian Surface is given by ##\phi=q_{enc}/\varepsilon_{o}## . It also states that any external field does not contribute to the Electric Flux through the Gaussian Surface. I am bit...
  4. diracdelta

    Energy flux in traveling waves

    Homework Statement Two threads, both having linear density μ1 and μ2 are connected and tensed with tension T. a) If traveling wave enters onto their junction, find ratios of amplitudes of reflected and input wave, transmitted and input wave, for μ2/μ1= 0, 1/4, 1, 4 and infinity b) Show that...
  5. J

    A small doubt about electric flux

    Hey there... As far as I know, electric flux is a scalar quantity which means that negative values are smaller than zero. This concept really confuses me since most of the exercises I dealt with suggest that negative flux somehow is larger than zero flux Example 1 the uniform field is directed...
  6. Ahmad Kishki

    Which Method to Use for Calculating Induced EMF: Flux Rule or Lorentz Force?

    to calculate emf i can use the flux rule -d(magnetic flux)/dt or the lorentz force line integral across the circuit. Is there a gudeline to follow for knowing when to use either (or both) of these methods? Thanks :D
  7. J

    Magnetic flux linkage and area as a vector

    Homework Statement A circular coil of diameter 24 mm has 40 turns. The coil is placed in a uniform magnetic field of flux density 85 mT with its plane perpendicular to the field lines. a) i Calculate the area of the coil ii The flux linkage through the coil. b) The coil was reversed in a...
  8. E

    Electric Flux: Definition, Equation & Examples

    Why is the electric flux defined as (electric field) x (area), Φ = EA? How do you come up with that equation? Is it because the electric flux is proportional to the charge and surface area?
  9. gfd43tg

    How Do Mass and Molar Velocities Differ in a Gas Mixture?

    Homework Statement A gas mixture contains 50% He and 50% O2 by volume at 500 K and 1 bar. The absolute mass fluxes of each species along the transportation direction z are ##\hat J_{He} = -0.8 \frac {kg}{m^{2} s}## and ##\hat J_{O_{2}} = 0.8 \frac {kg}{m^{2} s}##. Determine the mass and molar...
  10. 1

    Find the outward flux of a vector field across an ellipsoid

    Homework Statement [/B] Find the outward flux of the vector field ## \vec F = y^2e^{z^2+y^2} i + x^2 e^{z^2+x^2} j + z^2 e^{x^2+y^2} k## across that part of the ellipsoid $$ x^2 + y^2 + 4z^2 = 8$$ which lies in the region ##0 ≤ z ≤ 1## (Note: The two “horizontal discs” at the top and bottom are...
  11. S

    What is the magnetic flux through the prism's right side?

    Homework Statement Now, ignore the lengths given in the photo. Height (y) = .640 meters Length (z) = 1.18 meters Base (x) = .320 meters Magnetic Field (B) = 3.5 Teslas in the +X direction Homework Equations The problem is to find the magnetic flux through the surface of the...
  12. S

    Flux --> Apparent magnitude ( only 1 source )

    Hi guys, I've seen a lot of textbooks converting between 2 apparent magnitudes to the ratio of 2 fluxes. But I just want to know how to convert 1 ( ONE, UNO , 1, NOT 2 ) flux to 1 ( ONE, UNO, 1, NOT 2 ) 1 Apparent Magnitude. I think I saw my professor wrote this down, but am not sure . Is this...
  13. B

    Magnetic flux density calculation for high permeability material

    Hi to all of you, As the Biot-Savart-Law is based on experimentations in air, i like to know how to calculate the magnetic flux density in material with much greater permeability, where the circular like shape of the field distribution troughout the vicinity does not apply. Does anyone has a...
  14. R

    Control of Axial flux synchronous machine

    Hi all, Just a quick question about control of axial flux synchronous machine. Does it follow more or less the same technique ( which include PWM, inverter and dq transformation )? Is there any major difference from control of radial flux machine? Thanks in advance. Regards.
  15. Feodalherren

    Magnetic Flux & Current in a Dropped Magnet & Wire Loop

    Homework Statement A bar magnet is held above the center of a wire loop lying in the horizontal plane, as shown in the figure below. The south end of the magnet is toward the loop. After the magnet is dropped, what is true of the current in the resistor as viewed from above? (Select all that...
  16. D

    Problem in Magnetic Field and magnetic effect of electric current

    I read in class 10. I am having problem understanding magnetic fields, magnetic flux,magnetic flux density,magnetic field strength,magnetic permeability and strength of magnetic field produced due to a straight and closed loop current carrying conductor at a certain point at a certain distance...
  17. 2

    Does Magnetic Flux Remain Constant in Changing Magnetic Fields?

    I know that the equation for magnetic flux is \Phi=\int \vec{B} \cdot dA. It seems to me that this is like integrating the density function a rod with respect to x, which simply gives you the mass which is constant. I was wondering whether the same thing applies here: is magnetic flux a constant?
  18. M

    Flux linkage in terms of a straight conductor

    Taken from wikipedia, "If several turns of the wire are made, this becomes where N is the number of turns..." when speaking in terms of flux linkage and coils of a wire. However, in terms of a straight conductor (e.g. transmission lines), flux linkage for a meter long straight conductor has...
  19. deedsy

    Electric Flux through a sphere from a point charge

    Homework Statement I need to create an equation that can tell me the electric flux through the surface of a sphere (centered at the origin) due to a point charge placed at various locations in/around the sphere. For example, find the electric flux through the sphere (of radius = 1) with a point...
  20. A

    Electric Flux Through a 1x1x1 cm Box

    Homework Statement A 1x1x1 cm box with edges aligned in the xyz-axes is in the electric field E = (350x + 150)i N/C, where x is in meters. What is the net electric flux through the box? Homework Equations flux = ExAx + EyAy + EzAz The Attempt at a Solution I substituted into the formula...
  21. A

    Flux integral and Gauss's theorem

    Homework Statement Please help me to solve this assignment. [/B] a) A vector field is given by v(x,y,z) = (y, x, z-x). Calculate the flux from this field out of the unit cube, given by x,y,z = [0,1]. b) Use Gauss's theorem to calculate the same flux. Check that you get the same...
  22. G

    Heat Flux Calculation: August-February Net Loss

    If mean seawater temperatures vary from 20C in August to 3C in February, for a patch of water with a depth of 10 meters, what is the net heat flux lost (in W m^-2) to the atmosphere from August to February?
  23. E

    What is the vector perpendicular to the surface given by z = Ax + By + C?

    [Q] Find the integral that represents the flux of the vector F = <x^2z, x^z, x^2z> through the surface S given by z = Ax + By + C for 0 <= x <= a and 0 <= y <= a, where A, B, C, and a are positive constants. From what I remember of the Flux. F dot n, where n is a a vector perpendicular to the...
  24. J

    Converstion of radiant flux (watts) to temperature (C)

    Hey all, I'm having some unique challenges on an optical system I've created, where I'm arraying several LEDs under 1 optic/reflector. We're beginning to see major degradation of the metallic coating that is applied to the part, and I'm tyring to quanitfy the temperature (converted from radiant...
  25. S

    Zero Electric Flux Through a Closed Surface

    I'm relearning basic electricity concepts and I can't find an answer to a situation I've thought up. Imagine a cube with no enclosed charge and an electric field through it parallel to two of its faces. Guass's law says that the flux should be zero because there is no enclosed charge. Every...
  26. S

    Question on zero electric flux through a closed surface.

    I'm relearning basic electricity concepts and I can't find an answer to a situation I've thought up. Imagine a cube with no enclosed charge and an electric field through it parallel to two of its faces. Guass's law says that the flux should be zero because there is no enclosed charge. Every...
  27. H

    What is the purpose of the Parker limit in astroparticle physics experiments?

    I am reading some papers about astroparticle physics and I see something like Parker limit (monopole). So what is the purpose of setting up this limit ? It is be used to get the expected number of particles per unit area per unit time for later experiments ? Thanks
  28. P

    Parameterising a cylinder and determining the flux.

    Hi, I am wondering how i could parameterise the following rectangular cross section of the hollow cylinder in cylindrical co-ordinates. If this surface is better parameterised via a different co-ordinate system then by all means use that system. After I have completed the parameterisation i...
  29. M

    Electric Flux of equilateral triangle

    Homework Statement What is the flux of the uniform electric field E=8 N/C through an equilateral triangle with the side a=1m, if the normal vector makes 60 degrees to the direction of the electric field. Homework Equations \phi=EAcosøThe Attempt at a Solution E=8 N/C A= √3/4 m^2 Is the ø in...
  30. S

    Flux above a flat horizontal surface

    So my question is, am I missing any key thing in answering the question below? Question: An electric flux of 149 N.m2/C passes through a flat horizontal surface that has an area of 0.67 m2. The flux is due to a uniform electric field. What is the magnitude of the electric field if the field...
  31. A

    Find the flux through the equilateral triangle with corners at

    Homework Statement Find the flux through the equilateral triangle with corners at the points (1m,0,0), (0,1m,0), and (0,0,1m) in x,y,z space (measured in meters) for an electric field with magnitude E=6N/C pointing (a) in the z direction, (b) parallel to the line y = x. Homework...
  32. P

    How Is Flux Calculated Through a Spherical Surface Using Spherical Coordinates?

    Homework Statement What is the flux of r(vector) though a spherical surface of radius a? Homework Equations to solve this use spherical coordinates. The Attempt at a Solution ∫a . ds
  33. lonewolf219

    Electric flux versus magnetic flux

    I'm taking E & M II... Would anyone agree that the following statements are true? An electric field changing in time gives rise to a displacement current. A magnetic field changing in time gives rise to an electromotive force.
  34. V

    Flux Limited Sample: What Is It & Why Use It?

    I have read it in many papers that this is a flux limited sample. But I have trouble in understanding what is the exact meaning of it and why do we use flux limited samples?
  35. R

    What Is the Correct Approach to Calculate Flux Through a Sphere?

    Homework Statement What is the flux of r through a spherical surface of radius a? Homework Equations I'm guessing I should use a surface integral? ∫v.da ? The Attempt at a Solution Plugging in: I would get ∫r.da ? but what is a small patch of a sphere? I'm kind of confused...
  36. A

    Calculating Flux on a Rubik's Cube with a Point Charge at the Center

    Each sub-cube of the puzzle has edges 3.0 cm in length. A 8.0 nC point charge lies at the puzzle's center. What is the flux through the one face of the sub-cube labeled with the logo? Note: Its referring to a Rubik's Cube that has 8 sub cubes I used the equation where i divided the charge by...
  37. J

    How to calculate the photon flux of monochromatic light?

    I'm quite confusing with the theoretical method to estimate photon flux in a media. The method I knew is use the density of photon multiplied by the velocity of photon. Considering the solid angle distribution, for a certain direction only a part of π/4π can be delivery, therefore the...
  38. F

    Relation of radiation wavelength and photosynthetic photon flux?

    Dear all, If I have the value of photosynthetic photon flux in unit [ micro mole per meter square per second] as an output for ultra violet sensor. How can I know the corresponding wavelength of that radiation ? and can I know from that wavelength what is the type of the ultraviolet...
  39. G

    Finding Current Flux Through Closed Surface

    Homework Statement Let J=xy^2(\hat{x}+\hat{y}+\hat{z}) A/m^2 denote the electrical current density filed -i.e, current flux per unit area - in a region of space represented in Cartesian coordinates. A current density of J=xy^2(\hat{x}+\hat{y}+\hat{z}) A/m^2 implies the flow of electrical...
  40. A

    Finding the resistance, magnetic flux, and current of a loop section

    ...based on the angle. Homework Statement Figure 30-78 shows a wire that has been bent into a circular arc of radius r = 24.0 cm, centered at O. A straight wire OP can be rotated about O and makes sliding contact with the arc at P. Another straight wire OQ completes the conducting...
  41. K

    Solar Neutrino Flux: Understanding Variables in Equation

    Homework Statement Hello Guys :) I have been studying neutrinos this term in physics and have been trying to calculate the neutrino flux on earth. I have found an equation but I am just unsure about what the variables in the equation stand for. Homework Equations F = N/(A t) = E/(A...
  42. T

    Electric Flux: Understand and Calculate

    what is meant by electric flux... and how does an electric flux gets 'cancelled'? can a electric flux exist even when electric field is zero??
  43. L

    Magnetic Flux through 1 loop due to current on the other

    The scenario is the following, I am given 2 loops with the same radius, r, a distance of d, and same current of I. In the left loop the current goes counter clockwise, in the right loop the current is clockwise. The two loops centers lie on the same axis which are perpendicular to the plane of...
  44. L

    Magnetic Flux through 1 loop due to current on the other

    The scenario is the following, I am given 2 loops with the same radius, r, a distance of d, and same current of I. In the left loop the current goes counter clockwise, in the right loop the current is clockwise. The two loops centers lie on the same axis which are perpendicular to the plane of...
  45. shanepitts

    A different definition of radiation flux

    Would anyone have a different explanation and maybe an example of radiation flux? Here is the Wikipedia definition "Radiation flux is a measure of the amount of radiation received by an object from a given source", which is quite clearly explained.
  46. D

    Is a Virtual Photon Flux the Same as Ether?

    Hi, I have a thought experiment I'd like to share along with a couple of quotes. First, we consider the moment when a body goes from have exactly zero charge to a +Q charge. At that moment, by definition of E field a distance r from point charge q, we have a field propagating from point...
  47. Greg Bernhardt

    Exploring Scalar and Vector Flux in Electromagnetism

    Definition/Summary Flux sometimes means total flow through a surface (a scalar), and sometimes means flow per unit area (a vector). In electromagnetism, flux always means total flow through a surface (a scalar), and is measured in webers (magnetic flux) or volt-metres (electric flux)...
  48. C

    What is meant by pressure being a momentum flux?

    hi, I have been working on equation of state and one of my article says pressure is a momentum flux. what is the physical meaning of this? they have written it as pressure =(1/3) *number density*volume*momentum please explain me the expression regards
  49. J

    Faraday's Law and Magnetic Flux

    Homework Statement Hi, this is not a homework problem per say but I am just struggling with some concepts related to my homework. I am struggling with the concepts of flux linkage and flux cutting. Are these one and the same thing? The following statement in my book is where my confusion has...
  50. J

    Magnetic field strength and magnetic flux

    Hi, please could someone help with my confusion over these two qauntities. In class we recently learned that magnetic field strength (B) is the number of flux lines (measured in Webers) per square metre. The magnetic flux on the other hand is the total number of flux lines (measured in Webers)...
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