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.

View More On Wikipedia.org
Recent contents Top users
  1. Tom-Physics

    Magnetic field lines and the Sun

    Homework Statement Hey! I have trouble with an exercise that I need help with. Here it is: The magnetic field lines for the average interplanetary magnetic field (IMF) follow Archimedean spirals. i) Find the heliocentric distance r in Astronomical Units (AU), where a field line has wrapped...
  2. A

    Magnetic field lines form loops?

    Apart from the orientation of a compass needle and the pattern formed by iron filings, what other proof do we have of magnetic field lines forming loops?
  3. D

    Understand Field Lines: Positive & Negative Atoms

    Homework Statement https://www.google.se/search?q=f%C3%A4ltlinje&rlz=1C1_____enSE665SE665&espv=2&biw=1366&bih=643&source=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMI9dTNgquLyQIVhJIsCh1NxQZU#tbm=isch&q=physics+field+lines&imgrc=rKecBAfLOMsOoM%3A Why are the field lines on the positive atom pointed...
  4. K

    Electric and Magnetic Field lines

    Homework Statement The figure shows crossed uniform electric and magnetic fields and, at a certain instant, the velocity vectors of the 10 charged particles listed in the table. (The vectors are not drawn to scale.) The speeds given in the table are either less than or greater than E/B (see...
  5. O

    Potential magnetic field lines and Stokes theorem....

    Hi, A potential magnetic field has no curl. According to the "curl theorem" or stokes theorem, a vector field with no curl does not close. Yet, Maxwell's equation tell us we shall not have magnetic monopoles, so the loops have to close... ? What am I missing to remove this apparent paradox of a...
  6. nomadreid

    Electric field lines from a moving charged particle

    The electric field emanating from charged particle travels at the speed of light; fine. To pose an unrealistic thought experiment (a more realistic, if more complicated, thought experiment could replace this one, but the unrealistic one gives the idea), if a proton were to suddenly pop into...
  7. gracy

    How electric field lines going out from surface is zero?

    in the video above the instructor explains from time 8:22 to 8:55 that how and why electric field lines going out from the surface which do not enclose charge is zero but I don't understand then why not electric field lines going out from the spherical surface ( enclosing charge) is...
  8. gracy

    Electric field lines of positive source charge end on ....?

    I have read that electric field lines of positive source charge end on negative charge and Today I came to know that electric field lines of positive source charge end on infinity,which one is correct?I think electric field lines of positive source charge end on infinity if the positive source...
  9. gracy

    Doubts on properties of electric field lines

    In my book following points have been given 1-due to conservative nature of electric field ,the electrostatic field lines will not form any closed loop.I want to ask how forming a loop makes if non conservative? 2-Field lines have tendency to contract in length (longitudinal contraction )like a...
  10. DoobleD

    Dipole EM wave field lines VS decreasing amplitude

    The E and B field lines of a dipole radiating EM waves looks like that (sorry for the poor quality) : What I wonder is how can we see that the amplitude of the fields decrease as 1 / r? When you look as such a picture it actually feels likes the amplitude should rises. The E field gets...
  11. ATY

    Coronal hole and magnetic field

    Hey guys, I have a question. I am doing some homework for university and got super confused (probably just messing up things). So in school you learn that magnetic monopols do not exist. But my question is now: On the sun there are coronal holes, region where the magnetic field is not able to...
  12. SquidgyGuff

    Electric field lines extending to infinity?

    Given a system of two charges (+7q and -q) some of the field lines will terminate at -q while others go on towards infinity. I've read that the portion of the field lines that terminate is given by (1/7), but I have no idea why that is. I am supposed to find the maxium angle of a field line...
  13. A

    Non Uniform Electric Field Lines Problem

    Ok we know that the electric field(uniform or non uniform) is a conservative field. Imagine three horizontal electric field lines in '+X' direction separated by unequal distances let's say line 1 and 2 is separated by distance 'a' and line 2 and 3 is separted by some distance 'b' such that...
  14. Luke Cohen

    Are field lines from a magnetic dipole equal in magnitude?

    http://www.physics.sjsu.edu/becker/physics51/images/28_03_Earth_magnetic_field.jpg If this is your magnetic dipole and you start at the north end and follow a field line to the south end, is the magnetic field equal in magnitude the entire way through?
  15. I

    Constructing Field Lines for a Vector Field with Inverse Distance Dependence

    Homework Statement Determine the field lines of the vector field ##\vec F = (x^2+y^2)^{-1} (-y\hat x + x\hat y)## Homework Equations Definition of a field line ##\frac{d\vec r (\tau ) }{d\tau } = C \vec F (\vec r (\tau )) ## The Attempt at a Solution From the above equation and choosing...
  16. T

    Understanding Gravitational Field Lines Between Two Objects

    Homework Statement "Complete the diagram to display gravitational field lines between two objects of equal mass." Homework Equations N/A as question is descriptive.The Attempt at a Solution Okay, I know it's a bit of a mess but what I'm trying to show here is that the fields are radial and...
  17. rumborak

    "Reconnection" of magnetic field lines

    This is a bit vague, but I remember reading that during stuff like coronal ejections, magnetic field lines "reconnect". Now, does that not suppose "loose" magnet lines in the process? Which to my understanding do not exist?
  18. L

    Pictures of Magnetic Field Lines

    I have looked in vain on the web for pictures of magnetic field lines for multiple linked current loops. I would be happy just to see a picture of the field lines for a simple Hopf link but somewhere there must be pictures for the Borromean rings and other more complex links - and also braids...
  19. H

    Understanding Magnetic Field Lines: Fact or Fiction?

    Are magnetic field lines actually lines? To me, they are just a way to pictorially represent the magnetic field, and there are no lines. BUT, whenever you do the experiment with magnetic filings on a piece of paper, they align in actual lines. HELP!
  20. END

    Charge of q5 in Electric Field Map with q4 and q6

    Homework Statement The electric field map is shown below. (Take it to be a self-consistent scale drawing at a particular moment in time.) where \mathrm{q}_4 = +10 C, \mathrm{q}_6 = +10 C What is the charge of \mathrm{q}_5 ? Homework EquationsThe Attempt at a Solution I've tried the...
  21. H

    Magnetic field lines in a ring magnet

    Say if I magnetize a hollow cylindrical ring magnet by placing a staight current carrying wire along its axis. It will be magnetized with magnetic field lines running inside the cylinder clockwise or anticlockwise! So there will be no magnetic field lines outside the iron body? If I have a...
  22. AbhiFromXtraZ

    Can anyone draw the Field Lines of Faraday induced electric field

    Suppose there is an uniform magnetic field along z-direction. Now someone turns off the field. Then there will be an induced electric field. Can anybody draw this induced electric field lines? I know the electric field will curl around. But where will be the centre of that curl. Do the electric...
  23. schrodingerscat11

    Electric field lines from very long cylinders and thin disks

    Homework Statement Good day everyone. I am studying Gaussian cylindrical surfaces. I have three questions: (1) Books would say that the electric field lines would emanate from the lateral side of the cylinder and that the ends will not contribute anything. I cannot understand this because...
  24. H

    Electric Field Direction & Drawing Electric Field Lines

    The electric field in some region is found to have a constant direction . What you coclude about the charge in the region...?? How can I draw the electric field lines..?? :/
  25. J

    Magnetic Field Lines around a Magnet

    Hi, please could someone explain why the magnetic field is stronger at the poles of a magnet. I know that the field line density is strongest at the poles and more spaced out in the middle. I get that. I just wanted to know why the magnetic field is stronger at the poles than the middle of a...
  26. J

    Are electric field lines and electric flux the same thing?

    I don't believe they are because the field lines don't have a representation such as flux but I want to be sure. Also are flux lines a vector quantity?
  27. C

    Magnetic field lines of earth

    I need help understanding a certain problem. It basically stated: an airplane accumulated a positive charge, heading westward above the equator. Find the direction of the force (using the lame right hand rule thing). The problem I had was figuring out was whether the magnetic field would hit...
  28. R

    Electric field lines produced by two eccentric charged cylinders

    Homework Statement This is the theory for a laboratory session. If we have two hollow cylinders, one with radius r1 and the other with radius r7, the center of the first one being placed at a distance d from the center of the second one, what are the surfaces having the same electric...
  29. V

    Field lines from a line of charge

    I have a general gauss' law/electric field question. In calculating the electric field of a cylindrical shape, gauss' law can be applied to find that the Electric field only points aways from the surface of the cylinder (aka, in the s-hat direction). But this means that there are no field...
  30. Saitama

    Finding Flux through a Disk due to Two Charges

    Homework Statement Homework Equations The Attempt at a Solution The given field lines are at a maximum distance exactly midway between the charges but I don't know which equation to use to find it. Any help is appreciated. Thanks!
  31. S

    Field lines near the equilibrium point

    Homework Statement Charges 4q and -q are located at the points (-2a,0,0) and (-a,0,0), respectively. Write down the potential θ(x,y) for points in the xy plane, and then use a Taylor expansion to find an approximate expression for θ near the origin, which you can quickly show is the...
  32. M

    What's wrong with this diagram of magnetic field lines?

    I was looking through a book on magnetism and it had the attached diagrams of field lines and stated that the classical diagram of field lines exiting the N pole and entering the S pole is incorrect. They claim their diagram is the correct representation of the magnetic field lines. Their...
  33. A

    Magnetic Field Lines: What Causes Gaps?

    Hello All, I was just checking magnetic field lines as in attached figure. I am curious to see some gaps between adjecent field lines in the figure. Why it is not like a sheath( for example in lighting field) but as lines? Thanx in advance Abraham
  34. Entanglement

    Wire cutting magnetic field lines

    I have read in my schoolbook that when a wire of length l moves at velocity v in a magnetic field cutting the flux lines an emf is induced which it is calculated from emf = blv, I understand that emf is induced at time variation of magnetic flux across the wire, but I Can't see any change in the...
  35. xortdsc

    Field lines of electrons in an atomic orbital

    Hello, I have a rather conceptual question I couldn't really find an answer to yet. The electric field lines of an isolated resting electron would simply point from everywhere in space towards the position the electron is located in, with a length inversely proportional to the squared distance...
  36. M

    Higer dims: Electromagnetic field lines and stereographic projection

    I've noticed that electromagnetic field lines are very similar to stereographic projection of 3D sphere on 2D surface. Pictures below. In such comparison, electric field represents longitude and magnetic field represents latitude. For more visualization see...
  37. T

    Calculating Magnetic Field Lines

    I guess this is maybe more of a vector calculus question, but here it goes. Say I have an arbitrary current distribution \vec{J} with the corresponding magnetic field given by \vec{\nabla}\times\vec{H} = \vec{J} \vec{\nabla}\cdot\vec{H} = 0 What is the best way to calculate the field/flow...
  38. J

    Regarding electric field lines

    So if you have one positive charge and one negative charge (both with the same arbitrary number of field lines) close to each other, could you theoretically move a 2nd positive charge as close as desired to the first positive charge without them repelling? Or am i misunderstanding the concept of...
  39. M

    Electric field lines between 20/30 V point charges vs. 10/0 V

    Homework Statement What would the electric field lines / equipotential lines look like between point charges that are set up with potentials of 20 volts and 30 volts versus point charges that are set up with potentials of 0 volts and 10 volts? The Attempt at a Solution At first I thought the...
  40. R

    Magnetic field lines through copper

    Hello. Assume an electron gun, as in CRT, made of plumbing copper instead of glass. Using magnetic scanning coils to move electron beam. Will the displacements of this beam be linear as if tube material was made of glass ? PS : this is not an exercise by though but a real problem I encounter in...
  41. A

    Intersection of electric field lines.

    Field lines do not intersect because at their point of intersection,we would get two tangents indicating two directions of electric field at that point. Suppose the two filed lines JUST touch at a single point. wouldnt there be only a single tangent at the point??
  42. mesa

    Quetion about direction of magnetic field lines

    I see textbooks assign directions to magnetic field lines, for example north poles extending outward and south flowing inward. Are these directions correct or just a way to help tie the concept together and have just been arbitrarily picked much in the same way as conventional current?
  43. S

    Magnetic field lines of current carrying conductor follow property ?

    The lines of flux of the magnet possesses the following properties: 1)Forms closed loop 2)Starts from N-pole and closes at S-pole 3)Do not intersect each other 4)Parallel line and same direction repels each other 5)Parallel line and opposite direction attract each other So...
  44. J

    Do External Electric Fields Penetrate Conductors with Cavities?

    So I'm a little confused. My question is: If a conductor is placed in an external electric field, do the field lines penetrate the conductor? My original thought was yes they do and then the induced field inside the conductor cancels out the external field so that the net field inside the...
  45. T

    Testing for Charges in X-Y Plane Given Field Lines

    Homework Statement The Electric field lines in an X-Y plane are given in the attached image. The field is defined as E=αi(vector)y at x=0 and x=some distance along the positive X axis. α is a positive constant. Test for charges in the X-Y plane Homework Equations N/A The Attempt...
  46. jaumzaum

    Electric field lines in a cylinder

    In the figure below we have 2 hollow cylinder conductors. The red conductor has radius R1 and negative charge (Q1). We then introduce the blue conductor (radius R2), first connected to the Earth by a conductor thread. Then we disconnect the thread making the blue conductor charge be positive...
  47. E

    How do we draw electric field lines for a negative charge in a vacuum?

    Suppose we have two charges in vacuum. They are positive and negative. If we want to draw the electric field lines around the negative charge. Do we draw the lines inward (negative) or outward (field lines produced by the +ve on -ve). I remember that free body diagram on a bidy does not include...
  48. A

    Understanding Electric Flux and Field Lines in a Uniform Electric Field

    Homework Statement A uniform electric field of magnitude 6.5 \frac{N}{C} passes through a circle of radius 12 cm. What is the electric flux through the circle when its face is perpendicular to the field lines. The Attempt at a Solution The only problem with this question is picturing the...
  49. B

    Electric Field Lines Can't Cross Each Other?

    Hello, This query isn't concerned with solving a problem, but only with details appendant to the problem. The question is as follows: A uniformly charged ring of radius 10.0 cm has a total charge of 64.0 µC. Find the electric field on the axis of the ring at the following distances from...
  50. N

    Field Lines in TOKAMAK: Pictures & How to Understand

    How look field lines in TOKAMAK? Do you have any picture? How I could physically make for a better understanding? (of paper, laser, ...)
Back
Top