What is Magnet: Definition and 907 Discussions

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets.
A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism.
Ferromagnetic materials can be divided into magnetically "soft" materials like annealed iron, which can be magnetized but do not tend to stay magnetized, and magnetically "hard" materials, which do. Permanent magnets are made from "hard" ferromagnetic materials such as alnico and ferrite that are subjected to special processing in a strong magnetic field during manufacture to align their internal microcrystalline structure, making them very hard to demagnetize. To demagnetize a saturated magnet, a certain magnetic field must be applied, and this threshold depends on coercivity of the respective material. "Hard" materials have high coercivity, whereas "soft" materials have low coercivity. The overall strength of a magnet is measured by its magnetic moment or, alternatively, the total magnetic flux it produces. The local strength of magnetism in a material is measured by its magnetization.
An electromagnet is made from a coil of wire that acts as a magnet when an electric current passes through it but stops being a magnet when the current stops. Often, the coil is wrapped around a core of "soft" ferromagnetic material such as mild steel, which greatly enhances the magnetic field produced by the coil.

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  1. G

    Does a photo-resistor create an AC current?

    I'm a high school physics student. I want to do an experiment to see what happens when a high frequency alternating current goes through a magnet. To create the high frequency alternating current could a photo resistor do that for me? Does the photo-resistor create an alternating current with a...
  2. T

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  3. A

    Why Do Magnets with Different Field Homogeneities Experience Equal Attraction?

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  4. M

    What are the equations for calculating velocity with varying 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...
  5. B

    Generating EMF in a Coil with a Bar Magnet - 65 Characters

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  6. C

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  7. D

    What happens when a magnet falls through a copper pipe?

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  8. V

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  9. T

    Buy Small Superconductors Online | Explore the World of Superconductivity

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  10. P

    Question about north and south poles of a magnet.

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  11. M

    How Do Bar Magnets Create Zero Magnetic Field at Point P?

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  12. Physics GOD

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  13. R

    Big rotor vs multiple small rotors in a Permanent Magnet Generator

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  14. R

    Calculating Inductance of a Solenoid with Multiple Isolated Loops

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  15. A

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  16. A

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  17. E

    If I throw an iron ball at a magnet, the ball will bounce of

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  18. P

    Calculating Work for Permanent Magnet Fields

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  19. MironeDagains

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  20. Ankhen

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  21. A

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  22. Baluncore

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  23. D

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  24. S

    Working principle of quasi Halbach moving magnet linear motor

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  25. Dare Diamond

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  26. J

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  27. kvyn

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  28. Salvador

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  29. M

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  30. Salvador

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  31. Ankhen

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  32. S

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  33. S

    Can a smaller magnet still repel with the same force as a larger magnet?

    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...
  34. R

    How to find the magnetic flux of this magnet?

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  35. P

    Magnetic Rotation: Will South Pole Move to North?

    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?
  36. R

    Does a solenoid wrapped around a magnet meet resistance?

    If a solenoid were wrapped around a bar magnet, and a charge were applied through the solenoid, would there be resistance?
  37. Y

    Specs for a magnet to trigger a magnetic reed switch?

    Hello, for a project I'm working on i need a magnet that is attached to a spinning wheel to trigger a magnetic reed switch that's about a cm away every time that the wheel makes a rotation. I don't know which parts to buy because if the magnet is too weak or the switch too hard to trigger it...
  38. Z

    Pendulum & Magnet: Explaining Theory of Equilibrium Effect

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  39. 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...
  40. D

    Distance to which magnets start attracting each other

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  41. S

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  42. S

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  43. sergiokapone

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  44. R

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  45. L

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  46. S

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  47. E

    Scientists make nanofibers using fridge magnet & ferrofluid

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  48. F

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  49. T

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  50. T

    A question regarding an experiment with a magnet and a tube

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