Regarding magnetic shielding....

In summary, to protect a place from magnetic fields, soft iron is placed around the place. This soft iron becomes an induced magnet when a magnetic field passes through it, creating induced fields. However, this does not fully shield the place from the magnetic field due to the effects of diamagnetism and paramagnetism. The process of magnetic shielding is complex and involves factors such as the structure of the material and its magnetic susceptibility. Further research into these concepts can provide a better understanding of how magnetic shielding works.
  • #1
harvey1999
12
1
To protect a place from magnetic fields, soft iron is placed around the place, right?
so when magnetic field passes through the soft iron, the soft iron becomes an induced magnet, thereby creating induced fields, which makes no sense as the induced fields would still hit the place. please explain in simple terms? thank you.
 
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  • #2
Google: faraday cage.
 
  • #3
I've read about different types of iron just a little and it appears some forms of iron, particularly soft iron do not make permanent magnets, but instead have small domains everywhere where inside the iron there are millions of small permanent magnets whose magnetic fields point in every direction and thereby pretty much cancel. Meanwhile, there is another effect (besides ferromagnetism), called diamagnetism, where the free (conduction) electrons in the iron will partially shield any magnetic field, because the free electrons will respond to an applied magnetic field in such a way (.g. making circular orbits) as to generate magnetic fields of their own that oppose the applied magnetic field. In diamagnetism (as opposed to ferromagnetism), the response is opposite that of the applied field. I can't claim to be an authority on this subject, but I do think this is accurate.
 
  • #5
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  • #6
Have a look at the links please.
 
  • #7
Simon Bridge said:
Have a look at the links please.
Thank you. The screening mentioned in the "links" by the superconductors is particularly interesting. The diamagnetism exhibited by these (i.e. which results in the Meissner effect), is apparently very much stronger than that of ordinary (conductor) materials with free electrons. Additional comment is a system of free electrons, like those found in a conductor, would be expected, by Le Chatlier's principle, to respond in such a manner as to reduce the effect of the applied magnetic field.
 
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  • #8
If anyone thinks the secondary school model for how conductors can screen out EM is incomplete, they are correct.
However, it is a very good approximation that was demonstrated by Faraday and many others since.
The role of magnetic susceptability in screening magnetic fields should be investigated by the student also - this will be behind the mention of soft iron in post #1 - but, hopefully, the links will have answered the concerns Harvey1999 originally had.
 
  • #9
Simon Bridge said:
If anyone thinks the secondary school model for how conductors can screen out EM is incomplete, they are correct.
However, it is a very good approximation that was demonstrated by Faraday and many others since.
The role of magnetic susceptability in screening magnetic fields should be investigated by the student also - this will be behind the mention of soft iron in post #1 - but, hopefully, the links will have answered the concerns Harvey1999 originally had.
thank you
 
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Likes Simon Bridge

1. What is magnetic shielding?

Magnetic shielding is the process of using materials to redirect or absorb magnetic fields in order to protect sensitive equipment or living organisms from the effects of these fields.

2. How does magnetic shielding work?

Magnetic shielding works by using materials with high magnetic permeability, such as iron or nickel, to redirect magnetic field lines away from the protected area. This creates a barrier that prevents the magnetic field from reaching the sensitive equipment or organism.

3. What are some common applications of magnetic shielding?

Magnetic shielding is commonly used in electronic devices, such as computers and cell phones, to prevent interference from external magnetic fields. It is also used in medical equipment to protect patients from the strong magnetic fields generated by MRI machines.

4. Can magnetic shielding be used to protect against all types of magnetic fields?

No, magnetic shielding is not effective against all types of magnetic fields. It is most effective against static or low frequency magnetic fields, but may not be as effective against high frequency or rapidly changing magnetic fields.

5. Are there any potential health risks associated with magnetic shielding?

There are currently no known health risks associated with magnetic shielding. However, it is important to properly design and install magnetic shielding to ensure that it is effective and does not create any unintended consequences.

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