Read about magnet | 93 Discussions | Page 3

  1. M

    Non-uniform acceleration

    I thought i would do some digging into the wonderful world of magnets, and I found some things that... well are real head scratchers... I was wondering if anyone here could help me wrap my brain around non uniform acceleration. I'm trying to calculate velocity using distance and varying...
  2. G

    Is it possible to create a magnetic wire out of iron?

    In other words, would a iron wire be magnetic at the tip? If i put the wire in contact with a bar magnet would it get stronger?
  3. V

    Magnet moving over surface creating levitation

    Hi, I've been doing reading on Halbach Arrays moving over surfaces and generating repulsive forces. From my understanding, the moving magnet induces a circular electric current in the metal track, which gives rise to a magnetic field. However, I'm having trouble understanding why this field...
  4. T

    Superconductor Question

    Hello, I have been looking at superconductors lately and was wondering if there was anywhere I could get a small superconductor online. I realize for it to actually conduct it must be incredibly cold, but I was wondering where I could get a metal that allows for superconduction.
  5. Physics GOD

    Torque of an electric motor?

    Can someone tell me if the parts of what i've done are right, and explain the questions i've missed. We have just done a lab on split-ring commutators and i'm currently doing a lab report. "Explain what is meant by the torque of an electric motor. Use a diagram" I've said that 'The torque of an...
  6. R

    Inductance of wire loops

    I found this formula to approximate the inductance of a coil of wire. But what if a solenoid were composed of N separate loops, where each loop of the solenoid is connected to its own battery? That is, what if the solenoid had the same number of loops and the same geometry, except that each loop...
  7. P

    Work done by permanent magnet

    Hi, I would like to evaluate the required work to create a 1 T field with a permanent magnet. I saw a few formulas on the internet, but I don't know how to use them correctly. The main one are B={{\mu }_{0}}\left( H+M \right) {{W}_{mag}}=\frac{{{B}^{2}}}{2{{\mu }_{0}}}Vol Let's say I know all...
  8. MironeDagains

    Very basic electromagnet vs permanent magnet question

    When you switch on an electromagnet (who's north pole is pointing to the left), is it the same thing as if you had pushed a permanent magnet to the left? Or to the right? I believe it's to the left. But apparently my textbook thinks it's to the right. Who's correct? Why I'm asking: I've...
  9. D

    Question about opposing magnets

    My fundamental question is, do opposing magnetic fields eventually degrade each other over time? If they do, is there a way to mitigate or eliminate their ability to degrade one another? If I had one permanent magnet facing up and another permanent magnet facing down hovering over it (with the...
  10. Dare Diamond

    Maximum Voltage To Apply To An Air core Electromagnet

    Hello everyone. I am glad I came across this science oriented Forum site. I actually get there from Google and what I am deeply curious to know about is the amount of Maximum Voltage my 3.5kg Air Core Electromagnet can bear. The Core of the Solenoid is 120mm in height and 13inches in...
  11. kvyn

    How does rotating a magnet affect the magnetic field?

    I'm doing an experiment on the effect of the speed of rotation of a rare earth magnet on the voltage generated in a solenoid coil. I was wondering, how does rotating the magnet affect the magnetic field? The experiment setup is similar to the one below:
  12. M

    Magnetic wheels...

    I have a project I'm working on where I need to have a model train be able to have an electromagnet hold its wheels to the track -- so that it can go "upsides down" and resist derailment. I'm making the wheels and the track -- so all options are on the table. If I used a steel track (say...
  13. S

    Repel forces of magnets

    Hi Just wanted to know, If I have two magnets of the same size with a pull force of say 30kg and use them to repel each other, the top magnet at a position close to the surface of the bottom magnet would be able to support around 30kg (I know repel force is not measured in kg). If I then...
  14. S

    Repel forces of magnets

    Hi Just wanted to know, If I have two magnets of the same size with a pull force of say 30kg and use them to repel each other, the top magnet at a position close to the surface of the bottom magnet would be able to support around 30kg (I know repel force is not measured in kg). If I then...
  15. P

    Magnetic Rotation

    If I have a magnetic setup in frictionless, etc. area as follows: N / / / ---------------------S Will the "south" pole rotate up to the "north" pole, causing the system as a whole to rotate?
  16. CyanGrinMonk

    Why does a stationary magnet cause plasma to spin ?

    Hello, this is my first post, i only have what we call an O Level Physics here in the UK, but i have a strong layperson's interest in the subject, so i'm looking forward to picking the brains of the more educated people here. My friend's professor showed him something very interesting, all to...
  17. D

    Distance to which magnets start attracting each other

    Hi, I was wondering whether it was posible with a formula to measure the distance to which two equal magnets start attracting to each other. I was looking at this web page and I am not sure if this is the right formula. I have two...
  18. L

    Lightest Strongest magnet I can buy

    Hi All, I am wanting to buy the lightest, strongest magnet I can. Can someone please direct me or give me guidance on this issue? I am requiring a magnetic field of >5000 surface gauss. Any links or direction would be terrific, Thanks in advance, Dale.
  19. S

    Working with magnetism, solenoid

    Homework Statement A bar magnet is held stationary (with respect to the loop of wire) at the centre of the loop with the North pole sticking out one end and the South pole sticking out the other. What happens to the size of any EMF induced in the loop once the magnet has been replaced by a...
  20. milkman_78

    Size constraints of generators

    Based on what I have gathered so far, I don't see why a micro-scale generator wouldn't work, but then again I am a geographer with modest calculus skills. My biggest problem is not knowing how much I don't know, and I am hoping some kind and wise soul on PF can cure my ignorance. Let's say I...
  21. T

    General Solution of a Poisson Equation of a magnetic array

    Hi, I'll give some background, say you've got a planar structure of thickness 'd', lying on the z plane. Also say the upper and lower surfaces are y = 0 and y = -d, respectively. The structure has scalar potentials inside it as so: As you can see the vector fields cancel out on one side, As it...
  22. hackhard

    Electromagnet to attract small iron pieces

    i want to build an electromagnet which can attract small iron pieces(2-3 mm long) at a distance of 10 cm from the magnet.I am using 24 awg. magnet wire.Please help .answer these questions - 1) How long magnet wire (24 awg) do i need? 2)How much current 3) what shud be least radius of solenoid 4)...
  23. M

    Magnetic Fields of batteries

    1. I have heard that if you take 4 batteries and 2 non-coated wires, and run the wires + to -, with current flowing in opposing directions, with the wires in close proximity, that a magnetic field will be created between the 2 wires. Is this true? 2. Since photons have no charge, is there...
  24. H

    Does a moving magnetic field generate a current?

    Hey! Not sure if this is a stupid question or not but I was wondering if a moving magnetic field could generate a current in a wire. I know that moving a wire through a magnetic field creates a current but what if you move around a magnet underneath a circular wire. Does that generate a current?
  25. T

    Help Please: Is it possible to make an electromagnet w 2 like ends?

    HELP! Is it possible to create an electromagnet with one continuous wire with 2 like poles (i.e. both ends either north or south)?. Visualising it with the right hand screw rule for current carrying coils, it will be like the picture below, but one end of the coil will be as shown, while the...
  26. rothran

    Measuring magnetic field of a solenoid relative to distance

    So, I recorded the result of a LabQuest 2 Vernier Magnetic Field Sensor on different points of a plane, with a solenoid in middle with a 5 amp current running through. I want to compare my results with theory, but have no idea what equation i'm supposed to be using. I assumed it was B = μ0ηI/r3...
  27. AdityaDev

    Diamagnetism and orbital magnetic moment

    For diamagnetic materials, when an external magnetic field is applied, the electrons having orbital magnetic moment in opposite directions spped up. how does this happen? The direction of magnetic momwnt is given by right hand thum rule. If there is an electron revolving in anticlockwise...
  28. S

    Magnetic Gloves for scaling skyscrapers

    Hi! I was wondering how I would go about solving a problem like this: (I have experience with up to multi-variable calculus and moderate level physics) So I'm trying to see if it's plausible to create electromagnets, which fit into gloves and/or boots, that would allow a person to climb around...
  29. Y

    Magnet/Electricity to rotate object 90 degrees?

    Hello, I want to create a motion using electricity, using the cheapest means possible (DIY). Basically I'm trying to rotate an object 90degrees when the current is on, and back to its original position when the current is off. The questions are: 1) Is this possible? 2) Can this be done using...
  30. L

    Thought experiment on magnetic field propagation

    Some 30 years ago I learnt in the elementary school, that if I move a permanent magnet in a coil which ends are somehow electrically closed, than I need to apply force on the magnet, because the generated current creates a magnetic field which is against the magnet's field. However if the...