Two conceptual questions: Magnetism

In summary, magnets can attract non-magnets if they are made of iron or contain magnetic domains. When a magnet is placed near a neutral object, such as an iron nail, the nail will become temporarily magnetized and be attracted to the magnet. This is due to the alignment of the electrons in the nail, creating a magnetic field. This concept is related to the polarization concept of electricity and charged particles. A current loop can also be used to determine the presence of a magnetic field in a given region of space, using equations such as F=BIL and B=unI. However, there is no magnetic charge and the analogy between electric forces and magnetic forces breaks down.
  • #1
AznBoi
471
0
Questions #1: Will a nail be attracted to either pole of a magnet? Explain what is happening inside the nail when it is placed near the magnet.

My answer: Yes, the nail will be attracted to either pole of a magnet because the nail is neutral and has no charge whatsoever. When a magnet is placed near a nail, the nail will polarize, meaning that the electrons will move farther or closer depending on what pole of the magnet is closer to it. -- Is this concept of magnetism exactly related to the polarization concept of electricty and charged particles?

There is one thing I don't get, however. If magnets are similar to electrically charged particles (opposite poles attract and like poles repel), how do magnets attract neutral objects? Neutral objects have no poles but have atoms that have their charges balanced right? Do the magnets attract/repel the electrons? If so, is it because they exert a force on the neutral object because the electrons inside the neutral object are constantly orbiting (i.e. they have a velocity)? I know that in order for the magnetic field to exert a force on a charge, the charge needs to have a velocity. All electrons have a velocity in an atom correct? Why is it that magnets cannot attract non-metal/iron objects? If all objects contain atoms and therefore electrons, why is it that the magnet cannot attract the constantly moving electrons in its atoms?

Question #2
How can a current loop be used to determine the presence of a magnetic field in a given region of space?

My Answer: Well I know a couple of equation that might help me out: F=BIL, B=unI... but I'm not really understanding the concept behind this question. Please help me out here. Thanks in advance! :smile:
 
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  • #2
Can anyone please tell me if I'm going in the right direction for #1? Thanks.
 
  • #3
Magnets can attract nonmagnets if they are iron. Magnets won't just attract any neutrally charged particle. An iron nail may not be a permanent magnet, but it does have magnetic domains. Placing an iron nail in a magnetic field (near a permanent magnet) will allign its domains, and the two will attract. If you rub a magnet over a paper clip, it will be able to pick up other paper clips because its domains are temporarily alligned
 
  • #4
So magnets don't attract moving electrons in the atoms of objects? What are the domains that you have metioned?
 
  • #5
AznBoi, the analogy between electric forces and magnetic forces breaks down because there is no magnetic charge. You're right that the unmagnetised nail will be attracted to the magnet at either pole. This is because the nail becomes temporarily magnetised. In a ferromagnetic material this is because the motions of the electrons line up and create a magnetic field. Generally charges moving in circles make a magnetic field like a bar magnet.

It's all in Faraday and Maxwell's equations.
 

1. What is magnetism?

Magnetism is a physical phenomenon that results from the force between electrically charged particles. It is the property of certain materials, such as iron and nickel, to attract or repel each other based on their orientation and polarity.

2. How does magnetism work?

Magnetism works through the alignment of magnetic domains within a material. These domains consist of groups of atoms with aligned magnetic fields. When these domains are aligned, they create a net magnetic field that can attract or repel other magnetic materials.

3. What is the difference between magnetic and non-magnetic materials?

Magnetic materials are those that can be magnetized and have magnetic properties, such as iron, nickel, and cobalt. Non-magnetic materials, such as wood, plastic, and glass, do not have these properties and cannot be magnetized.

4. What are the practical applications of magnetism?

Magnetism has many practical applications, such as in motors and generators, where it is used to convert mechanical energy into electrical energy and vice versa. It is also used in magnetic storage devices, such as hard drives, and in medical imaging, such as MRI machines.

5. Can magnetism be turned off?

Yes, magnetism can be turned off by altering the alignment of the magnetic domains within a material. This can be done by heating the material above its Curie temperature, which disrupts the alignment, or by applying an opposing magnetic field to cancel out the existing one.

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