Magnet Definition and 912 Threads

  1. Natcox012

    Optimizing Magnet Use for Selective Pulling on Objects: A Scientific Inquiry

    Alright guys working on an experiment try to find out more info on the subject. Please move to the right part of forum if not in the right place. I put this here since I'm dealing with electro magnets. Here is my question is it possible to use and electromagnet to pull down on let's say a metal...
  2. C

    Suspending a Magnet or Ferrous rod in a Tube

    Let us start with a bit of background information. I am working on seeing if I can construct a very small version of Keith Lofstrom's Launch Loop concept, to see how well I can get it to work. To do this, I am using a larger clear plastic tube as the sheath, and a smaller plastic tube with...
  3. W

    Determining the Poles of a Magnet Using a Hall Probe and Lab Equipment

    Homework Statement Determine the direction of the dipole moment of a magnet with unknown poles. You are given a Hall probe and can use other devices commonly found in a lab. Homework EquationsThe Attempt at a Solution I was thinking since the Hall probe uses voltage to determine the strength...
  4. Sveral

    Cutting a FeBa Magnet for a Bloch Wall

    Hello, could someone explain to me, how I should cut a FeBa magnet, if it has one pole facing upward and the other downward so that the bloch wall would be across the entire length of the magnet. The dimensions of the magnet at hand are 152 x 102 x 52 mm. The bloch wall runs across the entire...
  5. grandpa2390

    Determine Field Gradient of a Stern Gerlach Magnet....

    Homework Statement Here is the Problem. I have the Solution but am having trouble understanding parts of it. 1.1. Determine the field gradient of a 50-em-long Stem-Gerlach magnet that would produce a 1-mm separation at the detector between spin-up and spin-down silver atoms that are emitted...
  6. U

    How rubbing a needle on a magnet affects its polarity

    Homework Statement It is known that when rubbing a needle on a magnet, the needle will become magnetized. If you rub the needle on the north side of the magnet, will it point differently than if you rubbed it on the south side of the magnet? Does it matter what direction you rub the needle...
  7. K

    Inducing electricity w/ moving piece of metal, static magnet

    Hi! I'm curious to know, whether it is possible to produce electricity by moving a piece of metal over a magnet (i.e a immobile magnet and a moving piece of metal close to the magnet), and how this would be done in practice.
  8. N

    Relation between electron and magnet

    Hi! In school I was thaught that magnet doesn't have anything to do with the motion of electrons, but then when you see the way electromagnetic induction work, it seems like the magnet move the electrons somehow. How is that possible and can we control the movement? Thanks a lot and sorry for my...
  9. E

    Spherical magnet dropped through aluminum pole rotates?

    Lenz's law shows that dropping a magnet through an aluminum pole will cause an induced current that slows down its fall drastically. I found a website that talks about this a little: https://www.lhup.edu/~dsimanek/TTT-slowfall/slowfall.htm It has the following question: I don't see any...
  10. I

    Obtaining position in a dipole field

    Hi all, Consider one has a magnetic dipole, the field given by: \begin{equation} \vec{B} = \frac{\mu_0}{4\pi}\left(\frac{3(\vec{m}\cdot\vec{r})\vec{r}}{r^5}-\frac{\vec{m}}{r^3}\right) \end{equation} where we can take $$\vec{m} = m\hat{y}$$. Let us say we have the a magnet vector which is...
  11. A

    Induced current in magnet (what would happen if....)

    Homework Statement Homework Equations N/A The Attempt at a Solution [/B] I'm having a lot of trouble understanding induced magnetic fields. I was wondering if someone can explain it for me and confirm if I have the right answers? a) I labelled it [North | South], and the direction of the...
  12. S

    What happens to the levitating height when more magnets are added?

    Imagine one magnet levitating above another. Now imagine another 3 magnets are added to the bottom magnet (image below). What would happen to the levitating height? I'd imagine the levitating height would increase and the force would increase by 4 times. I had a quick look online but I...
  13. C

    Is a flux density of 227.6 T realistic for a 5cm bar magnet?

    Flux density of a magnet is about how many T? In an experiment, I obtained the number 227.6 T. Is this a sensible value for a small (5cm long) bar magnet? Thank you~
  14. G

    Parallel magnet B-field strength

    , simple, Now I wonder what happens, I have a say speaker magnet or more precisely only the metal end plates that direct the b field lines or any other metal plate designed to guide a b field into a gap of sorts. Say I now apply a permanent neodymium magnet which has a magnetic field strength of...
  15. O

    Is it possible to stop a bullet by just using a magnet?

    Stop it or deflect it? and what are the laws and the effects that I need to know to determine something like this?
  16. S

    How Does Current Direction Affect Magnetic Field Orientation?

    Homework Statement current in wire is in east to west direction.direction of magneetic field below the line Homework Equations right hand thumb rule The Attempt at a Solution i used the right hand thumb rule to find the direction of magnetic field but the magnetic field comes out in in the...
  17. S

    I Where does the formula I = -e/T comes from?

    Yeah, where does it comes from?
  18. an_single_egg

    Is a moving magnet the only way to induce a current?

    Homework Statement My class was watching a video on electricity and magnetism, and after showing how current is induced in a loop of wire when a magnet moves through it, our teacher asked us if there is another way to induce current in a loop of wire - he told us that there were in fact two...
  19. T

    How Does Magnet Position Affect EMF in a Coiled Wire System?

    Homework Statement A bar magnet is attached to the end of a non-magnetic spring, with spring constant 484−1, as shown in the diagram. The other end of the spring is attached to a fixed force sensor which was zeroed when the magnet was at its equilibrium position, before being zeroed, the force...
  20. Y

    MOSFET or Rheostat or Potentiometer pros and cons?

    Preface: I'm a chemical engineering undergraduate student but as small-time and noob electrical engineering hobbyist. I really only have minimal experience in circuitry and the like. I want to build a series of electromagnets with a variable their strength in order to levitate an opposing...
  21. A

    How can the neutral outer core generate a magnetic field?

    Even if the outer core is convecting and conductive it is still charge neutral, so how can a Magnetic field be generated? Maxwells Equation say there needs to be net charge moving for a Magnetic field to be generated.
  22. C

    Induced current by moving bar magnet external to solenoid.

    Hi, I was wondering whether a bar magnet would induce a current if it was moving external to the solenoid, rather than within the coil. I see no reason why it wouldn't occur, but I've never seen it displayed or mentioned so I'm not sure. Thank you.
  23. B

    Magnet Coils & EMF Homework Help

    Homework Statement Homework EquationsThe Attempt at a Solution I got a Magnetic field by "Magnetized needle". I think it's just magnet. But i don't know how to get a magnetic flux due to the variable "d" that should be erased.
  24. C

    Need help doing force calculations with magnetism (between magnets)

    I am trying to calculate the forces (in Newtons) between a permanent magnet, and an electromagnet. All I can find is interactions between permanent magnets, electromagnets, but never both and it is getting really confusing for me to do the calculations. So basically, if I have a permanent...
  25. S

    What Causes the Strange Sound When Magnets Are Used with Headphones and a Disc?

    I did a little experiment the other day. It involved connecting headphones to a copper disc and a battery. Then I placed a magnet under the disc. When current flows with the magnet present I get this strange sound similar to squeezing ice. What am I hearing? I don't believe it to be the...
  26. C

    Bar magnet wrapped in electromagnetic coil

    If I wrap a coil around a bar magnet and shoot current through the coil so that the magnetic field of the electromagnet is at the same polarity of the bar magnet will I have amplified the magnetic field of the bar magnet maintaining the same magnetic shape but bigger/stronger?
  27. dlgoff

    Meter Movement Magnet Activity: 600-800 CPM

    The other day I used my Ludlum survey meter to check out if any of my old junk electrical part may show any traces of radioactivity. I was rather surprised to find an old meter movement magnet showed some activity. Today I took some pictures while determining just how much activity there was...
  28. Dadface

    I What Came First the Magnet or the Field?

    Below I paraphrase David Tong from: David Tong -- What is Quantum Field Theory? You can find this by googling. 1. "According to our best laws of physics the fundamental building blocks of nature are fields." 2." Every particle in the universe ... is a tiny ripple of the underlying field"...
  29. Martin Quevedo

    Neodymium magnet partial shielding

    Hi all distinguished members of this forum ! As my first post here I would like to open with a situation I have been struggling with I have attached a simple diagram of my problem I have 2 cylindrial N52 neodymium magnets axially aligned with each other with opposite poles facing each other...
  30. C

    Solutions of wave equation but not Maxwell equations

    Maxwell equation in absence of charges and currents are $$\nabla \cdot \bf{E} = 0 \\ \nabla\cdot B=0 \\ \nabla \times E=-\frac{\partial B}{\partial t} \\\nabla \times B=\mu \epsilon \frac{\partial E}{\partial t}$$ Wave equation is $$\nabla ^2 \bf{E}=\mu \epsilon \frac{\partial^2...
  31. J

    Can a magnet have more push force than it weighs?

    Simple question. Can a magnet have more push force than the magnet itself weighs. Example: A magnet weighing 2kg having a push force equal to 3kg.
  32. A

    How do you calculate the force between two magnetic dipoles?

    I've seen a couple of equations on Wikipedia and other sites and all of them are different. I need an equation as I want to specifically calculate the force between a magnet and a steel ball. The equations I've seen is this one here...
  33. G

    Magnetism - stability of a ring with a sphere inside it?

    Hey, is it possible to have a cylindrical ring (made of permanent magnet) and a magnetic sphere sitting inside it and staying in one place without touching the inner sides of the ring and not falling through? The object doesn't necessarily have to be a sphere. If it would work with any other...
  34. D

    Interaction between a neutral atom and an external magnetic field

    Lets suppose that I have a magnetic dipole moment at (0,0,0) pointing to the Z axis, and in the position (X,Y,Z) in the space, I have a Hydrogen atom, I would like to know the exact interaction between the magnetic field created by the magnetic dipole moment in (0,0,0) and the magnetic fields of...
  35. Qwerty42

    I Forces applied to a leaning levitating bicycle

    Hi! So I'm building an electromagnetic bicycle where the frame is levitating over the wheels, thus reducing the rolling friction to almost zero by removing the bearings. Magnets have also been placed alongside the wheels to provide side to side stability. Black is the frame, red are the magnets...
  36. alfab

    Why does the speed of the magnet matter in a coil?

    I am currently studying Faraday's law and electromagnets and in class we were told that if you had a coil and say a bar magnet was passed through it the faster the magnetic field was applied to the coil the greater the induced voltage or emf would be. I do not understand why the speed would...
  37. Undacuva

    Why Do Generators Use Coils Instead of Pipes?

    Hi, I understand you can induce an electrical current by passing a magnet through a copper pipe. If so, why do generators (and motors for that matter) use coils in stead? Do coils allow a stronger current or greater efficiency? Where can I go to find out the most energy-efficient design for a...
  38. F

    How Is Terminal Velocity Achieved by a Ring Falling Through a Magnetic Field?

    Homework Statement A cylindrical magnet with its axis vertical provides a radial magnetic field. A thin, circular aluminium ring that is co-axial with the magnet falls through the magnetic field. By finding an expression for the current in the ring when it is falling at the speed v, or...
  39. P

    How do I design a Permanent Magnet Synchronous Generator?

    Hi, I'm trying to do a very simple analysis on Simulink where I am applying a speed to a Permanent Magnet Synchronous Generator with a purely resistive load. I'm not familiar with PMSGs so the results I'm getting don't really make any sense to me. Could anyone go through some simple design...
  40. N

    Magnetic Torque on Dipole; Oscillating Magnet question

    Homework Statement A cylindrical bar magnet whose mass is 0.08 kg, diameter is 1 cm, length is 3 cm, and whose magnetic dipole moment is <5, 0, 0> A · m2 is suspended on a low-friction pivot in a region where external coils apply a magnetic field of <1.4,0,0> T You rotate the bar magnet...
  41. r_prieto5

    How Do You Calculate the Force of a Solenoid to Lock a Neodymium Triangle?

    Hello everyone, So for a personal project I want to calculate the force necessary for a solenoid (electromagnetic coil) to keep a permanent magnet triangle locked diagonally up and down at the same time so that it does not move in any direction. I need to know the values for coil thickness...
  42. cluelessGUY

    Magnet clamp repelling in coil

    I have a practical question. I want to make a rubber (silicone) hose/plug that is pinched closed by two magnets ( very strong magnets such as ones from a hard drive the Neodymium kind). I want to place then into a coil and when I want the liquid to flow, I want to turn on the coil and have the...
  43. SirHall

    Find magnetic field from temporary magnet

    What I've not been able to find after literally spending several hours researching is if you can find the formula to find the magnetic field strength from a temporary magnet. Or, to be put in better terms, what would be the force between two objects if one is a magnet and the other is something...
  44. Kbement

    Build a Magnet Generator with 42 Gauge Wire

    Hey everybody, So I've decided to try and make a copper wire magnet generator (real small) for part of my senior design project. If I can get this to work I can potentially reduce my fixture significantly. Anyways, I purchased some real small wind turbine generators off the shelf to play with...
  45. T

    Metal: no attraction to magnet and block magnetic fields?

    Hi, Can anyone help me in finding out a Diamagnetic or Paramagnetism or Ferromagnetism or any other metal which has following capabilities: 1- Should not be attractive towards magnet. 2- Should not allow magnetic fields to pass through inside. Thanks! THG
  46. P

    Does the magnetic field produced by a magnet act on itself?

    So when a conductor in complete circuit is placed next to a moving magnetic field, current in the conductor is induced and the induced current again produces its own magnetic field. So does this new magnetic field act on the conductor? It's the same as the question in the title. Is my concept...
  47. G

    Ballistic Lenz's Law: Magnet Induced Current in Copper Tube

    If a magnet was going fast enough as it approached/entered a copper tube, could the current induced in the tube via Lenz's Law be high enough to melt or even vaporize the tube?
  48. E

    B Does a moving bar magnet create charges?

    So I understand that a charged particle moving relative to me has a magnetic field, and does not have one if its stationary relative to me... So is it true that a magnet moving relative to me has a charge? Say I took a bar magnet and threw it away from me way out in space, would it acquire a...
  49. Shahsquatch

    Magnet Fundamentals and Iron Powder

    I am creating a product that incorporates magnetic sensing of magnetic nanoparticles. However due to their cost, I have decided to search for other avenues of testing. My question is about whether Iron Powder will retain a magnetic field once magnetized. I basically will place some iron powder...
  50. P

    Lorentz force on a charge due to a moving magnet

    Let's say I have a charge q which is viewed from its rest frame. So it's velocity v is 0. So the so-called magnetic component of its Lorentz force, which is q v x B, is 0. But I can have a magnet moving in this frame of reference. Let's say the velocity of this magnet according to the charge's...
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