What is Electric flux: Definition and 283 Discussions

In electromagnetism, electric flux is the measure of the electric field through a given surface, although an electric field in itself cannot flow. It is a way of describing the electric field strength at any distance from the charge causing the field.
The electric field E can exert a force on an electric charge at any point in space. The electric field is the gradient of the potential.

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  1. V

    Electric flux passing through a plane

    Homework Statement Given a 60-μC point charge located at origin, find the total electric flux passing through the plane z = 26 cm. Homework Equations The Attempt at a Solution Since electric flux lines from a point charge emanate in every possible direction, only a quarter of...
  2. H

    Electric Flux, Gauss's Law Problem

    Homework Statement A proton is a distance d/2 directly above the center of a square of side d. What is the magnitude of the electric flux through the square?Homework Equations 1. Electric flux, \Phi_{net} = \oint \vec{E}\cdot d\vec{A} 2. \Phi_{net} = \frac{q_{enc}}{\epsilon_{0}} 3. \vec{E} =...
  3. J

    Calculate Displacement Current from Electric Flux Density

    Homework Statement If electric flux density (D) is given by the vector (xy,yz,xz) then calculate the displacement current density Homework Equations Jd = dD/dt The Attempt at a Solution if you differentiate D, in terms of t, then you just get 0..but that apparently isn't the answer
  4. D

    Electric Flux Density: 4.5Xe + .50MV/m

    Homework Statement Given Xe=4.5 and E=.50 MV/m find the displacement flux densityHomework Equations D=ε0εrE εr=1+XeThe Attempt at a Solution Using the equation above I get (8.85e-12)(5.5)(.50e6)=.000024338 C/m^2 which is not what the answers say they give it in nC which I can't see how they can do?
  5. vmr101

    Calculate the electric flux piercing a cube?

    Homework Statement Consider four point charges q1, q2, q3 and q4, located at r1, r2, r3 and r4, respectively. (a) Calculate the electric flux piercing a cube (with side a and centered at r0 = (0, 0, 0) that contains all of these charges. (b) Calculate the electric field of the four charges...
  6. P

    Electric flux through a surface

    Homework Statement A point charge q is situated a distance d/2 above a square surface of side d as shown (see attached). a) It cannot be determined b) 2q/ε0d c) q/4\piε0 d) q/\piε0d2 e) q/6ε0 Homework Equations \Phi=qenc/ε0=\ointE*dA The Attempt at a Solution Shouldn't the...
  7. Y

    Gauss's Law, net electric flux

    Homework Statement The three small spheres shown in the figure below carry charges q1 = 4.30 nC, q2 = -7.70 nC, and q3 = 3.40 nC. Find the net electric flux through each of the following closed surfaces shown in cross section in the figure. Homework Equations...
  8. FOIWATER

    When does the surface charge density equal the electric flux density?

    Homework Statement The electric field intensity in polystyrene (relative permittivity 2.55) filling the space between the plates of a parallel plate capacitor is 10kV/m. The distance between the plates is 1.5mm. Calculate the surface charge density of free charge on the plates, and the surface...
  9. M

    Electric Flux Units: Understanding the Confusion | Explanation Included

    Units for electric flux is Nm2/C = (electric Field Strength)(Surface Area). However the units of electric flux are confusing because I though the definition of Electric flux was The number of electric field lines through an area of surface. Therefore I though Electric flux would have had...
  10. A

    Calculating Net Electric Flux in a Cylindrical Solid of Charge - Homework Help

    Homework Statement The charge distribution in the figure to the right is a cylindrical solid of charge q, radius R, and length H. The Gaussian surface S is a cylindrical shell with radius r and length h, with r > R. Determine the net electric flux given that q = 12Q, R = 5L, H = 6L, r does not...
  11. N

    Electric Flux on the surface of a sphere

    Homework Statement I'm trying to figure out an equation for finding the net flux that abandons the surface of a sphere which contains a line charge distribution an a charge density. The problem is: A line charge distribution of 0.6m long with a charge density equal to 5C/m, is contained...
  12. S

    Electric Flux: What it is & Why it's Zero on a Cylinder

    The defination of electric flux on wiki is "is the rate of flow per unit area of the electric field. Electric flux is proportional to the number of electric field lines going through a virtual surface". If we have a cylinder in an electric field placed along its length the net electric flux...
  13. M

    Electric Flux of Concentric Spheres

    Is we take two spherical conductors concentric with charge at centre.One of radius r then other of 2r..Will the electric flux through them will be equal? But when we use electric flux= E*A Then won't the electric flux vary as area is different of each sphere?
  14. E

    Calculating Electric Flux through a Square in the xy-Plane

    Homework Statement In a region of space there is an electirc field E that is in the z-direction and that has magnitude E=(964 N/(c*m))x. FInd the flux for this field through a square in the xy-plane at z=0 and with side length .350 m. One side of teh square is along the + x-axis and another...
  15. N

    Calculating Electric Flux Density in a Dielectric Material

    Hey. So if I have a condenser, where the electric field between the plates is equivalent to 50kV/m, the electric flux density D= ε0*50kV/m. If I insert a dielectic between the plates, the electric field will decrease to 10kV/m, and kappa (the relative permittivity) equals 5. So, will the flux...
  16. B

    Electric Flux and Charge Distribution in a Cube with Uniform Electric Fields

    Homework Statement Hello, the problem I am working on is: Assume the magnitude of the electric field on each face of the cube of edge L = 1.05 m in the figure below is uniform and the directions of the fields on each face are as indicated. (Take E1 = 31.5 N/C and E2 = 26.5 N/C.) (a) Find...
  17. B

    Generating Expressions For Electric Flux

    Homework Statement A particle with charge Q is located immediately above the center of the flat face of a hemisphere of radius R as shown in the figure below. (a) What is the electric flux through the curved surface? (Use any variable or symbol stated above along with the following as...
  18. T

    Electric flux through a plane described by an equation

    Homework Statement The elctric field in a certain region of space has components Ex = 6.0 N/C, Ey = 7.0 N/C, and Ez = 0. Find the electric flux though the surface x = 6y, 0 < x < 6.0 m, 0 < z < 1.0 m. What is the angle between the electric field and the unit vector normal to the...
  19. M

    Electric Flux Theory & Superposition | Find Electric Field at P

    https://www.smartphysics.com/Content/Media/Images/EM/03/h3_lineD.png In the image above, i was asked to find the electric field at point P. since the y-components cancel due to symmetry, i used he equation \Phi=\intE dA=Qenclosed/\epsilon . I found q1 and q2 by multiplying (charge density x...
  20. R

    Electric Flux thru the top face of a cube

    Homework Statement An electric field given by \vec E = 4.0 \hat i - 3.0(y^2+2) \hat j pierces a 2.0 meter by 2.0 meter by 2.0 meter cube. What is the electric flux thru the top face? Homework Equations \phi = \int \vec E \cdot d \vec A The Attempt at a Solution I'm aware that you...
  21. A

    Why do electric flux and charge have the same units?

    eletric flux and charge have same units ie coloumb is it a coincidence or some similarity exists btw these two? electric flux density D= εE is used for calculating flux ψ not E .why?(read tht it is done for practical reasons) please explain the practical reasons ,if any.
  22. O

    Electric flux, vector or scalar?

    I know that the electric flux is a scalar quantity, but the concept of the Electric flux seems to confused me. If the electric flux density is a vector quantity, how come the electric flux is a scalar quantity? For example, I have the electric flux density: D=20i+2j. Isn't it means...
  23. D

    The model of electric flux in solids

    hi there! I have a bit stupid question: Imagine a solid metal cylinder. We put a . Explain to me please the exact model of the direct current electric flux of the particles. Is there a "skin effect" when a direct current is in action ?
  24. J

    Why Do Different Sources Show Varying Electric Flux Equations?

    Homework Statement Im starting to read about the electric flux and gauss's law. I am reading two books, Serway and Schaums electromagnetics. The weird thing is that I'm getting different equations for the electric flux Serway says that the Electric flux ψ is ∫E ds = 1/ε ∫ρ dv =...
  25. iVenky

    What exactly is Electric Flux Density?

    We define flux density as D= ε E right? or even ∇.D=ρ But I can't link the above with what is given in the wiki where they have used the symbol "phi" http://en.wikipedia.org/wiki/Electric_flux What is the difference between D and symbol "phi"? I would be really happy if you could...
  26. B

    How Do You Calculate Electric Flux Through a Cube with a Central Charge?

    **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...
  27. S

    How Does Gauss' Law Apply to Infinite Charge Slabs?

    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 =...
  28. E

    The Electric Flux on all sides of a cube

    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...
  29. O

    Electric flux - Area vector question

    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...
  30. C

    Which Gaussian surfaces have an electric flux of +q/εo through them

    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!
  31. I

    Electric flux through a closed surface

    [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...
  32. B

    Magnetic Field Induced by Nonuniform Electric Flux

    Homework Statement During the design of a new doppler radar unit, you have two circular plates with radius R = 3 cm and a plate separation of d = 5 mm. The magnitude of the electric field between the plates is given as: E = (700 V/(m sec2))*(1-r/Rp)*t 2 where Rp is the radius of the plates...
  33. F

    Calculating Electric Flux Through a Cone

    Homework Statement A cone is resting on a tabletop as shown in the figure with its face horizontal. A uniform electric field of magnitude 4550 N/C points vertically upward. How much electric flux passes through the sloping side surface area of the cone? Homework Equations flux = ∫...
  34. T

    Finding the electric flux through a sphere

    Homework Statement A sphere of radius R is placed in a uniform electric field of E=233 N/C i. Find the electric flux into and out of the sphere. Homework Equations I understand that Gauss's Law is shown as... ∫E dot dA = Q/epsilon not The Attempt at a Solution Well, since...
  35. T

    Changing electric flux caused by a resistor

    I'm learning the basics about electromagnetism, including that a changing electric flux through an open surface causes a magnetic field. Obviously a capacitor causes this, but doesn't a resistor like a light bulb (whose resistance varies with temperature and therefore time) also cause this?
  36. K

    How Does Side Length Influence Electric Flux Through a Cube?

    A point charge 6.50 nC is at the center of a cube with sides of length 0.260 m. PART A: What is the electric flux through the surface of the cube? PART B: What is the electric flux through one of the six faces of the cube? ATTEMPT: A) Total flux enclosed by the cube = Q / eo...
  37. K

    Simple electric flux through tetrahedron problem

    A tetrahedron has an equilateral triangle base with 20-cm-long edges and three equilateral triangle sides. The base is parallel to the ground and a vertical uniform electric field of strength 200 N/C passes upward through the object. (a) What is the electric flux through the base? (b) What is...
  38. K

    Electric flux changing forumla variables

    A point charge Q at the center of a sphere of radius R produces an electric flux of (flux symbol) coming out of the sphere. If the charge remains the same but the radius of the sphere is doubled, the electric flux coming out of it will be? LINK TO ORIGINAL PROBLEM: http://i.imgur.com/e8Tmt.png...
  39. K

    Relativistic aberration and locally measured electric flux density

    Does relativistic aberration apply to electric fields and magnetic fields? If a spaceship accelerated to a relativistic speed with respect to an initial inertial frame, in a constant direction with respect to a uniform electric field, do the effects of aberration affect the magnitude of electric...
  40. M

    Calculating Electric Flux of Displacement Vector w/ Cylindrical Co-ords

    Using cylindrical co-ordinates (r, theta, z), calculate the electric flux phi=integral D . dS when the displacement vector D is given by: D=10ezcos(theta)/r2 . kr + z2sin(theta)/r2 . Kz and the surface S is part of a cylinder of radius a=0.3, defined by 0 is less than or equal to z which is...
  41. T

    Electric Flux Density for Coaxial Cable

    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...
  42. Z

    Electric flux charge through a cube

    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...
  43. V

    Calculating Electric Flux Through a Rectangle

    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...
  44. J

    Finding Electric Flux and Electric Fields

    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...
  45. T

    Need Help in Finding Electric Flux through a Hole in Sphere

    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...
  46. A

    Is the Electric Field Normal to the Surface?

    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...
  47. Y

    Calculating Electric Flux Leaving a Sphere from Point and Line Charges

    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...
  48. DocZaius

    Is Left Side of Gauss' Law equation not the total electric flux?

    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...
  49. D

    Electric Flux through Cylindrical Surface

    An infinite line of charge with charge density λ1 = -5 μC/cm is aligned with the y-axis as shown. I am pretty sure you are supposed to use Gauss' Law so I tried just calculating the total enclosed charge and dividing it by epsilon naught, but it's not working. I think maybe I have to use...
  50. N

    Calculating electric flux with a constant electric field

    Homework Statement A vertical electric field of magnitude 2 X 10^4 N/C exists above the Earth's surface on a day when a thunderstorm is brewing. A car with a rectangular size of 3.00 m by 1.50 m is traveling along a dry gravel roadway sloping downward at 7.0°. Determine the electric flux...
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