Magnetic Definition and 1000 Threads

Magnetism is a class of physical attributes that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. Magnetism is one aspect of the combined phenomenon of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only a few substances are ferromagnetic; the most common ones are iron, cobalt and nickel and their alloys. The rare-earth metals neodymium and samarium are less common examples. The prefix ferro- refers to iron, because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, Fe3O4.
All substances exhibit some type of magnetism. Magnetic materials are classified according to their bulk susceptibility. Ferromagnetism is responsible for most of the effects of magnetism encountered in everyday life, but there are actually several types of magnetism. Paramagnetic substances, such as aluminum and oxygen, are weakly attracted to an applied magnetic field; diamagnetic substances, such as copper and carbon, are weakly repelled; while antiferromagnetic materials, such as chromium and spin glasses, have a more complex relationship with a magnetic field. The force of a magnet on paramagnetic, diamagnetic, and antiferromagnetic materials is usually too weak to be felt and can be detected only by laboratory instruments, so in everyday life, these substances are often described as non-magnetic.
The magnetic state (or magnetic phase) of a material depends on temperature, pressure, and the applied magnetic field. A material may exhibit more than one form of magnetism as these variables change.
The strength of a magnetic field almost always decreases with distance, though the exact mathematical relationship between strength and distance varies. Different configurations of magnetic moments and electric currents can result in complicated magnetic fields.
Only magnetic dipoles have been observed, although some theories predict the existence of magnetic monopoles.

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  1. yashraj

    I Does a time varying magnetic field in vacuum produce electric field or not?

    Suppose there is very long current carrying wire. A charged particle is present somewhere around it. The current in the wire varies with time, thus by biot-savart's law there should be time varying magnetic field. I want to know that will this time varying magnetic field produce electric field...
  2. Adrian59

    A Calculating higher order terms for Electron Anomalous Magnetic Moment

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  3. BuggyWungos

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  4. P

    I Can someone explain the principle of magnetic levitation in this YouTube video?

    Can someone explain me the principle of magnetic levitation in this YouTube video?
  5. P

    I How could magnetic levitation technology be adapted for personal transportation?

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  6. phys9928

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  7. H

    A Magnetic Vorticies In Superconductors Don't Confine Electrons

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  8. ohwilleke

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  9. F

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  10. D

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  11. P

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  12. DaveC426913

    B Is the Sun's Magnetic Field About to Flip?

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  13. Bling Fizikst

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  14. F

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  15. M

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  16. hongseok

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  17. G

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  18. M

    B Solar Wind Particles, - reaching into Earth's magnetic field?

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  19. Kartofen69420

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  20. Graham87

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  21. jsnprt

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  22. maxelcat

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  23. G

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  24. F

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  25. A

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  26. K

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  27. tanmays1

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  28. fmorgan2

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  29. S

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  30. S

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  31. Szecska8

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  32. harryharns

    C/C++ Perform RK4 between 2 Clusters in Magnetic Field

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  33. ergospherical

    I Average magnetic moment of atom in magnetic field ##B##

    from the partition function - am trying to show that ##\langle \mu \rangle = \beta^{-1} (\partial \log Z / \partial B)## where ##Z## is the canonical partition function for one atom, i.e. ##Z = \sum_{m=-j}^{j} \mathrm{exp}(\mu_0 \beta B m)##, and ##\mu = \mu_0 m##. The average...
  34. D

    B Magnetic field and generator power output

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  35. rogdal

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  36. G

    B Should I use True North or Magnetic North to align my sundial?

    I'm not sure I asked the correct question. I am trying to learn when our sun is at solar 12 noon on my yard, does the sun light travel a perfect path across earth, 50% before solar 12 noon and 50% after solar 12 noon. I built a large sun dial in my yard 3 ft tall 6 ft long. I used a compass...
  37. milkism

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  38. M

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  39. B

    I How to depict a nuclear magnetic octupole

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  40. M

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  41. S

    Exploring Propulsion with Light & Magnetic Fields

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  42. S

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    There are a couple of problems with the same setup. On plugging in the values and solving for the integral, I am not getting the expected values of the force. Is there something wrong in the solution attached?
  43. F

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    So I thought I knew how to do this problem but I've run into some issues that make the algebra feel impossible and I am beginning to feel like I'm taking the wrong approach, I ended up rewriting it in a doc because I was concerned maybe my handwriting was the cause of my error so the work is...
  44. Brian Tsai

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  45. H

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  46. S

    B Magnetic Field & Particle Spin: Does It Matter?

    Does the magnetic field caused by moving particles depend on the particle spin value? Eg a stream of say protons spin 1/2 is creating a magnetic field. If the particles are (say) lithium nuclei spin 3/2 instead, does that create the same strength field ? (same conditions of course)
  47. milkism

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  48. milkism

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  49. Grizzly_1

    B Confusing diagram of a rotating coil in a magnetic field

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  50. B

    Flyback Converter Magnetic Flux Calculation

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