# 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. ### B Seeing both B field lines and E field lines at the same time

After watching this clip Electric Field Lines Lab I wonder if it is possible to see both electric field lines and magnetic field lines at the same time by swapping the two nails in the video with two bar magnets, as the conductors as we understand bar magnets are metals and metals are good...
2. ### Magnetic- and Electric- field lines due to a moving magnetic monopole

Question: My answer: What it looks like for an electric charge: Am I correct? If you want I can hand out my Latex on how I got to it, it will refer to the book Griffiths a lot.
3. ### Relationship between magnetic field lines and magnetic field

As stated in the problem, I want to demonstrate mathematically that field line density is directly related to the magnitude of B. How would I be able to do this, other than simply using the flux equation and showing that for a higher flux in the same area, the magnetic field must be rise...
4. ### Directing magnetic field lines by using diamagnetic material

I want to improve the magnetic field strength at the surface of a magnet configuration by utilizing diamagnetic materials to guide the magnetic field lines. I have not the proper equipment to measure the effect myself but would this work? This is the initial configuration with four magnets side...
5. ### I Question regarding the use of Electric flux and Field Lines

1)Field Lines is supposed to represent the electric field around a charge ,now we can draw infinite field lines around a charge and sinc Electric flux is No of Field Lines /area ,does it become infinite ,the whole concept of field lines is quite in the Gray Area for me ,I can in theory mark...
6. ### Electric field lines of H2O molecule

I wanted to post my work so far to see if I am on the right path toward the correct answer so far. I have attached a ss of the actual problem and my work in the attachments
7. ### A problem in graphing electric field lines

hi guys our instructor asked us to try to graph the projection of the electric field intensity at a certain point p(x,y) , for two charges q+-q located at (-a,0) , (a,0), Now starting with the equation $$\frac{dy}{dx} = \frac{E_{y}}{E_{x}}$$ after transforming this equation I got...
8. ### I Why are field lines parallel in a uniform field?

For a uniform field like this, I imagine the two plates that creates it are made of multiple atoms with charges, which are points sources that create radial fields. We know that radial fields don't have parallel fields lines, so how are parallel fields lines form when the field is made of...
9. ### Drawing Radial Field Equipotentials and Field Lines

I have just attached a standard depiction of a radial field as one may similarly choose to draw it. So I understand that the gravitational field strength in a field is defined as the force per unit mass at that point. The field lines in a radial field move further apart further away from the...
10. ### Changes in electric field lines as a result of an oscillating charge

The last couple of days I’ve been troubled with a specific part of electromagnetism. How will electric field lines be affected by an oscillating charge? More specific, what will happen with the “amplitude” of a wave in an electrical field line as the wave propagate away from the charge? 1. Will...
11. ### Magnetic field lines around electron and wire seem to contradict

In the picture below, the direction of the magnetic field lines can be determined by using the right-hand rule with the thumb pointing in the direction of the current. If we use the right hand rule in the picture below, thinking of the yellow arrow as the current, we would not get the correct...
12. ### Electric field lines between a point-charge and a conducting sheet

figure 1: → I don't understand how to approach this problem. Basically it asks for the distance r.I think I should use Gauss's law, but I've been thinking about the shape of the gaussian surface and I'm not sure about how it should look or where I should place it. Any help would be useful...
13. ### Finding equations for electric field lines

Hi, I am interested in finding the equation for electric field equipotential lines. Ideally, it would be nice to have one equation that worked to find it for different geometries. Unfortunately, I don't think that exists. Assuming it does not exist, I think I would probably have to either solve...
14. ### Force & energy in cutting and stretching magnetic field lines?

I have an ordinary switchable magnet for holding tools to a lathe. It's like a magnetic force gearbox, but I can't quite understand the force multiplication. When placed on a steel surface the switch force is approximately ~5N on both finger and thumb at 1.5cm radius acting over a 3cm arc...

16. ### Magnetic field lines and magnetic flux density

I'm trying to understand the relationship between the "number" of field lines passing through a region and the magnetic force in this region.I understand that the drawings are of course conceptual: we cannot draw "all" the field lines (although can be visualized with iron fillings).Also the...
17. ### Not necessarily homework help but I do not understand Field lines

Homework Statement: This is not for homework but I have an AP physics exam on field lines and am confused about the proportionality between the charges of objects and the number of field lines. Homework Equations: E=(k*q)/r^2 I am struggling with the number of field lines to put based on the...
18. ### Electric Field Lines: Should Earthed Plate Have No Charge?

Shouldn't the plate that is earthed be with no charge? making B correct. but the accepted answer was A.
19. ### Are Magnetic Field Lines Real? - Comments

Greg Bernhardt submitted a new blog post Are Magnetic Field Lines Real? Continue reading the Original Blog Post.
20. ### Electric Field Lines for Two Objects on a Frictionless Table

Homework Statement In the diagram, two small objects, each with a charge of -4.0nC, are held together by a 0.020 m length of insulating string. The objects are initially at rest on a horizontal, non conducting frictionless table & the effects of gravity on each other are negligible. (b)...
21. ### Understanding the Relationship Between Magnetic Field Lines and Force

Hello, I am unable to understand a certain (important) concept. We all know what the field lines of a permanent magnet look like. They go from north to south, and curve around the magnet. This direction (direction of the magnetic field) does NOT describe the direction of a force. And that's...
22. ### Determining the direction of electric field lines

In general, the field lines points away from the positive charge and toward the negative charge. The answer is letter E, but the second part of the answer says, "the magnitude of q1 is less than the magnitude of q2". Is that because q1 is negative and q2 is positive?
23. ### Question about Electric Field lines (MCQ)

*This is a question in an assignment that i have to submit. 1. Homework Statement Two imaginary spherical surfaces of radius (R) and (2R) respectively surround a positive point charge (Q) located at the center of the concentric spheres. What is the number of electric field lines (N2) going...
24. ### I Charged black hole - static electric field lines

Where do the static electric field lines appear to originate from a charged black hole, non rotating, Reissner–Nordström metric? I've had a number of qualified physicists say they appear to come from the center of the black hole, but people on these forums have said that doesn't make sense...
25. ### Angle of escaping electric field lines

Homework Statement Two charges 2q and -q are located at x = 0 and x = a respectively. There are field lines extending from the positive charge and lines going inwards to the negative charge. Some of these lines go from the positive charge to the negative, but some go off to infinity from the...
26. ### Magnetic field lines directed?

Is it possible to direct or confine field lines to be shaped like a laser? I know there are magnets such as neodymium cones that direct field lines through the tip but they don't seem to have the amount of pull as I'm looking for. If there isn't, is there anyway to amplify the power? Maybe align...
27. ### Electric field lines of a sphere in a uniform electric field

I need to draw electric field lines of sphere in uniform electric field with LaTeX/TikZ. Can anyone show me equation of field lines in polar coordinates?
28. ### Why does the solar wind follow magnetic field lines?

My physics teacher said that the northern lights are the product of charged particles coming from the sun and interactign with our atmosphere. I believe he said that these are deflected by Earth's magnetic field and directed towards the North and South poles. When I look at pictures on this...
29. ### Oscillation of a point charge perpendicular to field lines

Homework Statement Two particles A and B each carry a charge Q and are separated by a fixed distance D. A particle c with charge q and mass m is kept at the midpoint of A and B. If C is displaced perpendicular to AB by a distance x where x<<<D, find the time period of the oscillation of the...
30. ### Field lines for masses vs. electrons

Is there any difference between the field lines you draw when one mass approached another mass and when two electrons approach one another? If there is no difference, does this mean field lines can't be used to predict the forces both particles feel?
31. A

### Draw field lines for both magnetic fields

Homework Statement Homework Equations N/A The Attempt at a Solution Im not sure if I've done this right because it seems too little for 6 marks. I have arrows coming from the north to the south end for the magnet's magnetic field. I have arrows going counter clockwise around the conductor...
32. K

### Electric Field Lines: Charge Movement and Conductor/Insulator Interactions

1. The problem statement "If charges are free to move, the field lines will straighten and shorten as the charges move together" 2. Questions in relation to statement Are there any cases in which charges aren't free to move between two charged objects such as between conductors or insulators...
33. A

### Understanding Electric Field Lines: An Introduction to E Bar and Tangent Vectors

Hi, I'm reading the textbook and there is my image. http://imgur.com/a/9BqHm It says "The field vector E bar is tangent to the electric field line at each point". I might want to ask what "tangent" means in this sentence? Sorry to ask that stupid question.
34. ### Field lines of a electric charge immersed in two dielectrics

Homework Statement Hi guys, I hope you can help me with this problem, because I do not have any idea and I could not find anything that could help me, thank you in advance! Draw the electric field lines due to a punctual charge Q immersed in a dielectric medium with constant K1. Q is separated...
35. ### Are particles accelerated along magnetic field lines?

I have a question which puzzled me when I was reading up about auroras. When talking about the interaction of the solar wind and the Earth's magnetic field, the book said that "particles are accelerated along magnetic field lines towards the earth" That didn’t sound quite right, as I was taught...
36. ### Do charges accelerate because their field lines are changed?

I ask this because of this diagram. Say that two charges are held a certain distance apart and are let go. Well, we see that the field lines of one charge repels the other. And I noticed that the field lines for an accelerating charge also bends. So can we say that because one field...
37. P

### Em waves and magnetic field lines

So i know that magnetic field lines are closed, in an electromagnetc wave how can be these lines closed? i cannot picture this in my head
38. ### Plotting magnetic field lines between two adjacent NS poles

This question is regarding the magnetic field lines around two abutting alternating poles. Take two axially magnetised disc magnets and place them next to each other (like tangent circles), so on each side the adjacent or neighboring magnet is of the opposite pole. By sprinkling iron filings...
39. ### Electric Field Lines: Does Positive Test Charge Follow?

Does a positive test charge follows along the path of electric field lines if it is free to do so? I mean the trajectory of the charge is along the electric field lines and the field lines are not necessarily straight.
40. ### Field Lines of an Electric Dipole?

It isn't difficult to find the electric field of a dipole. However, it is tricky to find the field lines. All points of a field line have to be parallel to the electric field at those points. A tangent, which is the derivative, is parallel. We can hence formulate the equation for a field line...
41. ### I Dipole: Which field lines go to infinity?

Hi. An electric dipole field (two opposite point charges separated by some distance) has fields lines from the positive to the negative charge, but also field lines reaching to and coming from infinity. Starting from the positive charge, is there a way to compute the opening angle of the cone...
42. ### What do electric field lines look like for two metal plates?

Hello. I'm now taking accelerator physics class and the lectures said in the thermionic electron gun, anode metal mesh should be grounded in order to prevent electrons which traveled beyond the mesh from coming back due to the electric field lines. Without grounding of the anode, I believe...
43. ### Electric Field Lines: Can Charges Move on Conductors?

sir, we know that the electric field lines are perpendicular to the surface of the conductor ,it means charges are rest on the surface of the conductor ,there is no work done. if we create an electric field such that the electric field lines are at a different angle to the surface of the...
44. ### B Solenoid B field lines question

Hi, I wonder what would the path of magnetic field be in my case.I have a solenoid , it's a metal rod that has a winding in the middle of it, I need the magnetic field to come out of the rod not at the ends of it as is usually shown in pictures but at the surface side along each end of the metal...
45. ### Magnetic Induction: Homework Help

Homework Statement Homework Equations I am not really good at this topic, but I think you would need both the right hand rules (one that involves finding direction of current via magnetic field as well as the one for finding magnetic force) The Attempt at a Solution So I drew out magnetic...
46. ### Electric field lines from a metal shell and sphere

Homework Statement A metal sphere of charge +6μC is surrounded by a metal shell of net charge +6μC. Which of the following diagrams represents the electric field lines of the system? Homework EquationsThe Attempt at a Solution The correct answer provided by my teacher is a figure with 12...
47. ### MHB Another field lines of 3D vector functions question

I am trying to find the field lines of the 3D vector function F(x, y, z) = yi − xj +k. I began by finding dx/dt =y, dy/dt = -x, dz/dt = 1. From here I computed dy/dx = -x/y, and hence y^2 + x^2 = c. For dz/dt = 1, I found that z = t + C, where C is a constant. I am unsure where to go from...
48. ### MHB Field lines of 3D vector functions

My question regards finding the field lines of the 3D vector function F(x,y,z) = yzi + zxj + xyk. I was able to compute them to be at the curves x^2 - y^2 = C and x^2 -z^2 = D, where C and D are constants. From my understanding the field lines will occur at the intersection of these two...
49. ### Relationship between field lines and magnitude of charge

Hi, I am curious as to whether there is a relationship between field lines and magnitude of charge. For instance, is the sketch for the electric field of a +1.0 micro coulomb charge the same as the sketch for a +2.0 micro coulomb charge? Thanks. All help is very much appreciated!
50. ### Angle of electric field line heading to infinity

Homework Statement Charges 2q and -q are located on the x-axis at x=0 and x=a respectively. (a) Find the point on the x-axis where the electric field is zero, and make a rough sketch of some field lines. (b) You should find that some of the field lines that start on the 2q charge end up on...