What is Field lines: Definition and 210 Discussions

A field line is a graphical visual aid for visualizing vector fields. It consists of a directed line which is tangent to the field vector at each point along its length. A diagram showing a representative set of neighboring field lines is a common way of depicting a vector field in scientific and mathematical literature; this is called a field line diagram. They are used to show electric fields, magnetic fields, and gravitational fields among many other types. In fluid mechanics field lines showing the velocity field of a fluid flow are called streamlines.

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  1. L

    Direction of H Field Lines: North to South or South to North?

    does the H field lines go from north to south, or south to north? thanks
  2. Q

    6) How does computer software plot magnetic field lines?

    How does computer software plot magnetic field lines where the density of lines represent flux density? How does the software know which points to start plotting from in order to come out with a true representation?
  3. D

    How can magnetic field lines snap ?

    How can magnetic field lines "snap"? In astronomy, magnetic field lines around stars or planets are sometimes said to "snap" and release their stored energy. e.g. the aurora borealis is created that way http://www.atoptics.co.uk/highsky/auror2.htm Also gamma ray bursts of neutron stars...
  4. N

    Elementary confusion about the magnetic dipole moment and field lines

    simple magnetic dipole moment with impossible field lines? clueless. Hello, I'm taking a first year university course in electromagnetism. At a certain point we came upon the torque on a current loop in a uniform magnetic field. There we introduced the magnetic dipole moment \overline{\mu} =...
  5. Q

    Magnetic field lines of a moving electron

    A moving electron's magnetic field lines. How do the magnetic field lines of a moving electron in a straight line look? What about the magnetic field lines of a rotating hydrogen electron? I mean the magnetic field produced due to the electron's intrinsic spin and due to its movement in a line...
  6. L

    Understanding Equipotential Lines and Electric Field Lines

    I understand the concept of electric field lines but don't understand the interaction with the equipotential lines. I understand that along each equipotential line/surface that there is no change in potential energy. I also understand the field lines need to cross perpendicularly with the...
  7. B

    Magnetic Field Lines: Explaining Iron Filings Behaviour

    The magnetic field surrounding a bar-magnet (for example) is continuous. The lines that are drawn to depict the strength and direction of the field don't actually exist. They are akin to drawing contours on an OS map, are they not? What therefore explains the behaviour of iron filings when...
  8. V

    Drawing Field Lines: A Beginner's Guide

    I'm just a little confused about field lines. I have sketches of equipotentials and I'm supposed to draw the field lines on them. The one I'm looking at is a dipole with a floating electrode in the middle of the positive and neutral charge. The positive is 12V, and the floating point is 6V...
  9. D

    Do charges travel along field lines?

    Hi. I'm a student in AP Physics this year and we started the E&M portion this week and we learned about electric fields. I was watching MIT's OpenCourseWare in order to get more comfortable with the concepts. The lecturer said that charges do not follow electric field lines because of the...
  10. D

    Field lines of a ring of magnets?

    Hi I'm trying to build a permanent magnet alternator with a different approach than usual. Most PMAs have a ring of magnets alternating north and south. But I'm wondering what would the field lines look like if ALL the magnets faced one direction? Would it provide a useful magnetic field, or...
  11. R

    Uniformly distributed electric field lines

    Homework Statement A positive charge is placed in the center of a cube. Are the intersections of the field lines with a side of the box uniformly distributed across that side. Explain. === I have missed some lectures due to getting the swine flu (ugh) and the material is not exactly...
  12. G

    Electric field lines questions

    Homework Statement The electric field from two charges in the plane of the paper is represented by the dashed lines and arrows below. Select a response for each statement below. (Use 'North' towards top of page, and 'East' to the right) The force on a (-) test charge at N is directed...
  13. A

    Field Lines of Charged Particles: Speed & Emissions

    Like a radioactive particle emit rays, does this similar to the field lines of a charged particle? at what speed these field lines are generated from the charge particle?
  14. A

    The Deceptive Nature of Field Lines

    what is the meaning of deceptivness of field line?? i mean for 2d surface field line = n/2pi*r (f.l. inversly proportional to r) but for 3d surface f.l.= n/4pi*r^2 (f.l. inversly proportional to r^2), since electric field = kq/r^2?? what is the reason behind it? it written in the...
  15. D

    Electricity and magnetism field lines

    Are electricity and magnetism field lines the same? please be detailed!
  16. J

    Oscillating Electric Field Lines

    I'm have some conceptual problems with electric fields and waves. When I think of electromagnetic waves I imagine field lines emanating from a charge that is oscillating, consequently causing the field lines to oscillate. In diagrams showing field lines, the electric field runs parallel with the...
  17. B

    Angle made by electric field lines

    Homework Statement an electric field line emerges from a positive point charge +q1 at an angle x to the straight line joining it to a negative charge -q2.at what angle y will the field line enter the charge -q2? Homework Equations The Attempt at a Solution sin(y/2)=sin(x/2)(q1/q2)^1/2
  18. M

    Electrical field lines in conductive wire

    Hi we connect a Voltage to heads of a conductive wire how will be the field lines inside Wire ? (cylinder wire) E = \rho J so ? :D field lines are parrarell inside wire ? in whole wire Electrical field is constant ? (J must be more in center of wire) what about Extreme...
  19. Z

    Do Gravitational Field Lines Exist Similar to Magnetic and Electric Field Lines?

    Can they exist ?? Like Magnetic Field lines and Electric Field lines
  20. F

    Magnetic Field Lines: Can They Be Broken?

    Is it possible for magnetic field lines to be broken?
  21. I

    Finding the force of magnetic field lines

    Homework Statement A wire carrying 15 A of current has a length of 17 cm in a magnetic field of 0.80 T. The force on a current-carrying wire in a uniform magnetic field can be found using the equation F = BIL sin θ. Find the force on the wire for each of the following angles between the wire...
  22. M

    Sketching Field Lines of f(r)r: A Guiding Intuition

    1. The problem statement, all variables and givenknown data Let r be a position vector from the origin (r=xi+yj+zk), whose magnitude is r, and let f(r) be a scalar function of r. Sketch the field lines of f(r)r Homework Equations 1 \nablax(\nabla\Psi)=0 2...
  23. W

    Magnetic monopoles, electric field lines and equipotential surfaces

    Homework Statement (i) Explain why it would not be possible to write the magnetic Field (B-field) in terms of a vector potential (A) IF magnetic monopoles existed. (ii) For an electrostatic field (E-field), define the electrostatic potential (Fi), and explain CONCISELY what is meant by a...
  24. J

    Understanding Electric Field Lines: Curving and Splitting Nodes

    Homework Statement Hey I'm supposed to draw electric fields for this problem and I can't figure these 2 out. Homework Equations There really isn't any. The Attempt at a Solution It's included in the picture http://img135.imageshack.us/my.php?image=physicsge1.jpg
  25. J

    Drawing Electric Field Lines and Equipotential Lines

    Homework Statement You have two metal electrodes, not touching each other. One is a circle and one is like a thin plank. The plank is at a lower electric potential. Draw electric field lines between them, including direction. Draw equipotential lines in the space between the electrodes...
  26. L

    High & Low Resistivity Effects on Magnetic Field Lines

    Homework Statement Two of the MHD equations can be formulated as \vec{E} + \vec{v} \times \vec{B} = \eta \vec{J} \nabla \times \vec{B} = \mu_0 \vec{J} where [itex]\eta[/tex] is the resistivity of the plasma. a.) Derive an equation for the magnetic field at very high resistivity and...
  27. D

    Sketching Electric Field Lines of Circular Arc w/ Uniform Charge

    Homework Statement Sketch a field line picture for a circular arc with a uniform linear charge density. Homework Equations The Attempt at a Solution To do this do I just break up each segment on the arc into small segments each of charge dQ and draw the field line along the...
  28. A

    Unraveling the Mysteries of Magnets and Field Lines

    I know that anything casting a field obeys the inverse square law and that field lines are an abstract used to help us visualise the vectors on objects effected by the field. Why is it then that if I drop iron filings around a magnet they sort themselves into neat lines? I would expect that to...
  29. W

    Divergence-free field has closed field lines?

    Is the restriction that a field is divergence-free enough to ensure the field lines will be closed? How can one (dis-) prove such a statement?
  30. K

    Defibrillator and electric field lines

    I am asked to draw a picture of a person 1 second before patient is defibrillated and 10 seconds after a patient is defibrillated. I am asked to draw a general picutre of the electric field lines and charges at these two points. I know that the goal of defibrillation is to enterfere with the...
  31. S

    Electric field lines in a dielectric_ figure attached in ee thread

    Hi all, I am trying to solve numerically as well as model the electric field lines coming out of a electrode (not a point charge) in a dielectric medium. ANy suggestions would be greatly beneficial _________________________________________________ _ separated by d + separated by d _...
  32. S

    Help to solve electric field lines in a dielectric

    Hi all, I am trying to solve numerically as well as model the electric field lines coming out of a electrode (not a point charge) in a dielectric medium. ANy suggestions would be greatly beneficial _________________________________________________ _ separated by d...
  33. C

    Experiment with Electric field lines

    Homework Statement Hello all. I need help or ideas on making an experiment in which I need to show the electric field lines. I think it should be somewhat similar the the experiment when you put lots of little metal pieces on a piece of paper and then you put a magnet below the paper, and...
  34. C

    Magnetic and Electric Field Lines

    Homework Statement Magnetic and electric field lines are visually defined by field lines. Give three points to explain how the field lines can be used to describe the characteristics of these fields. Homework Equations (Not sure if needed to describe) Fm = qvBsin0, Fm = IlBsin0 The...
  35. V

    Field lines and Coulomb Forces

    The field intencity around a little spherical conductor changes with reverse ratio to the square of their distance. Then let us put another little spherical charged conductor in field of first one. The field lines are no more change with the reverse ratio to the square of their distance(they are...
  36. G

    Why are Field Lines Always Perpendicular to a Conducting Line?

    Why the field lines are always perpendicular to the conducting line?
  37. S

    Do gravitational field lines always need to be straight? Example?

    do gravitational field lines always need to be straight, can't they be just curves if yes then please tell an example..?
  38. J

    What can we determine about the electric field lines from two charges Q1 and Q2?

    Hello Everyone! i need some guide and hints about this... Here is the link for the picture... From the figure, the electric Field lines arising from two charges Q1 and Q2 are shown. From this drawing we can see that A) The electric field could be zero at P2 B) Both Q1 and Q2 have the...
  39. P

    Who Discovered Coulomb's Law and the Concept of Electric Field Lines?

    Does anyone know when Coulomb discovered his law? And does anyone know when the concept of electric field lines was invented? I know that Faraday created the idea for the magnetic field and I was wondering if it was he who applied it to the electric field or was it someone else? Sources of...
  40. T

    Understanding the Electrical Field Lines of a Charged Insulating Disk

    Homework Statement Sketch the electrical field lines of a uniformly charged insulating disk. Show field lines close and far away. Homework Equations none, conceptual The Attempt at a Solution For close to the surface of disk near the center the field lines are almost perpendicular...
  41. I

    Understanding Field Lines: Exploring Vector Fields

    Homework Statement describe what field lines are (7 marks) Homework Equations The Attempt at a Solution A field line is a locus that is defined by a vector field and a starting location within the field. A vector field defines a direction at all points in space; a field line may...
  42. A

    Sketching Electric Field Patterns for Charged Objects

    Homework Statement a) Sketch the electric field pattern setup by a postively charged hollow sphere. Include regions inside and regions outside the sphere. b) A conducting cube is given a positive charge. Sketch the electric field pattern both inside and outside the cube. The Attempt at a...
  43. A

    Examples of Electric Field Lines

    Does anyone know a good site where they show you examples of how to draw Electic Field lines? Problem relating to it: a) sketch the electirc field pattern set up by a positively charged hollow sphere.
  44. I

    Solving the Differential Eqn. for Field Lines of Vector Fn.

    I'm not sure under what heading this belongs but I'm going to ask here: Show that the field lines y = y(x) of a vector function \mathbf F(x,y) = \mathbf i F_x(x,y)+\mathbf j F_y(x,y) are solutions of the differential equation \frac {dy} {dx} = \frac {F_y(x,y)} {F_x(x,y)} Could someone...
  45. N

    Electric Field Lines: Symmetry between Opposite Charges

    I know that the electric field lines between two oppositely charged points are symmetric, but I can't seem tof ind any refrence as to when this symmetry breaks down. I want to say that electric field lines do not maintain symmetry if the two charges are not equal but opposite, e.g. a -4 and...
  46. iamhumble

    Windows Sofware To Graph Electric Field Lines ?

    Windows Sofware To Graph Electric Field Lines ?? Hi Everyone, Does anyone know of any Windows software out there that will graph electric field lines? I recently did a physics lab where I determine point charges of some "x-rays" and from the data I gathered I need to graph the electric...
  47. J

    Quick question reguarding electrical field lines.

    Can anyone answer me a curious question. Why are electric field lines perpendicular to equipotential lines? Is it because force and charge are inversly proportional or is there a more simple reason? Thanks.
  48. P

    Understanding the Direction of Magnetic Field Lines to Coil Diagrams

    Magnetic Field Lines Question http://img101.imageshack.us/img101/9819/coil2sm.jpg Could someone tell me which is the direction of these magnetic field lines and why?
  49. I

    Parametric Representation of Field Lines

    F(x,y,z)=(-\frac{y^2+2z^2}{x^2},\frac{2y}{x},\frac{4z}{x}) "Find parametric representations of the field lines." How do I parametrize all possible field lines?
  50. H

    Magnetic Field Lines in Motors: Exploring Real-Life Behavior and Possible Errors

    Hi, I have a question about magnetic field lines in a motor-like situation. Suppose I have two horizontal bar magnets, with one north end parallel to x=-X and one south end parallel to x=X, as here: -- -- |...
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