Permanent Magnet vs. Electromagnet: What's the Difference?

In summary: Just to be clear, permanent magnets do not have current flowing through them. Take a screwdriver or other piece of iron/steel and repeatedly stroke along the length of it with a permanent magnet. The more often done, the more the piece of metal will become... magnetized.
  • #36
What does the North pole and South pole of a magnet do ??
 
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  • #37
Xidike said:
I tried But Can not Understand :)

what specifically didnt you understand ?

give an example


D
 
  • #38
It was written:
"In metallurgy, stainless steel is defined as a steel alloy with a minimum of 11.5% chromium content by mass"

What Is metallurgy ?? What is Chromium ??
 
  • #39
type metallurgy into google

chromium is a metal
 
  • #40
What does the North pole and South pole of a magnet do ??
 
  • #41
Buckleymanor said:
Is iron not suitable to be made into a magnet but suitable to become an electro magnet.
What do you mean by remnance.

Do you have access to a computer? Have you tried Google for finding the meanings of words?
We're here to discuss things, not to spoon feed people.
[Edit: despite my abysmal spelling of the word, Google gives all you need to know when you add the term 'magnet']
 
Last edited:
  • #42
Xidike said:
What does the North pole and South pole of a magnet do ??

I think this is easily found on any site that explains magnets.
 
  • #43
sophiecentaur said:
Do you have access to a computer? Have you tried Google for finding the meanings of words?
We're here to discuss things, not to spoon feed people.
[Edit: despite my abysmal spelling of the word, Google gives all you need to know when you add the term 'magnet']
Google seems to contradict what you said that's why I asked or I have misunderstood.
Remanence or remanent magnetization is the magnetization left behind in a ferromagnetic material (such as iron) after an external magnetic field is removed.

Which is a quote from wiki ok it don't say how much or if any remnent of magnetisation is left behind but I reckon it's not zero like you stated because of the wording.
 
  • #44
OK. 'Soft Iron' has very low remanence and makes a very poor permanent magnet. It is also very easily magnetised whist the applied field is there. Perfect when you want to control the magnetic field (solenoid in a starter motor etc. or a relay). Steel is harder to magnetise and will remain magnetised. The right grade of steel of other ferromagnetic alloy is even harder to magnetise and will stay magnetised for longer (impervious to being bashed, for instance).
I don't think Wiki and I disagree, do we? The general term 'iron' doesn't always refer to soft iron but to cast iron, for instanceor 'iron age tools' - which have a higher remanence. You would have found that out if you had read around more, I am certain.
 
  • #45
What does the North pole and South pole of a magnet do ??
 
  • #46
What does wiki tell you?
 
  • #47
I read About Magnet on Wikipedia Can't find my answer :(
It was written
"For a bar magnet, the direction of the magnetic moment points from the magnet's south pole to its north pole"
What does it means ?
 
  • #48
Was wiki the only place you found anything about magnets? For some easy level info, include "key stage three" or "key stage four" in your google search.
 
  • #49
the compass which tells the direction of magnetic field, is the special type of compass or a normal compass ?
 
  • #50
Compass is so simple, elementary device that I can't imagine what the special one would be.
Or are you confusing magnetic compass with the one you use in geometry for drawing circles?
 
  • #51
How the compass tell the direction of north and south pole of a magnet ?
 
  • #52
xAxis said:
Compass is so simple, elementary device that I can't imagine what the special one would be.
Or are you confusing magnetic compass with the one you use in geometry for drawing circles?

Some 'English Pedantry' here. The thing you draw circles with is officially called a 'Pair of Compasses'. No idea why but the two things do actually have different names.

I am beginning to wonder just how much reading Xidike is doing. This stuff is described all over the Web at many different levels - and not only in English, I'm sure.
 
  • #53
Xidike said:
How the compass tell the direction of north and south pole of a magnet ?

Find out what a compass is made of.
 
  • #54
The Compass I have, I don't know of which material it is made of.. But when I take my magnet near to it,, it does not attract the magnet,, but the needle of compass is affected by the magnet..
 
  • #55
Xidike said:
How the compass tell the direction of north and south pole of a magnet ?

You are still asking questions about stuff you could have easily found out for yourself. I did a quick search and, amongst an avalanche of useful sites, I found this one which has answers to all of your questions, afaics. HERE. Please read this thoroughly before asking any more questions.
 
  • #56
Thanks Man... That was a great article.. It increased my knowledge a lot about magnetism.. But I still Can't find my answer.. that how compass tell the direction of North And South Pole Of Earth And Magnet..
 
  • #57
Opposite poles attract. What does that tell you about a compass needle?
 
  • #58
Xidike said:
Thanks Man... That was a great article.. It increased my knowledge a lot about magnetism.. But I still Can't find my answer.. that how compass tell the direction of North And South Pole Of Earth And Magnet..

What about the diagram of magnetic field lines? Isn't that clear enough? I don't think you read carefully enough. The small compass needle lays along the lines.
 
  • #59
Drakkith said:
Opposite poles attract. What does that tell you about a compass needle?

I know that like poles repel each other and opposite attract each other..
Answer of my question was not there
 
  • #60
I am beginning to question your motives for posting on PF. Are you just trying to wind people up? (It's working, I think)
 
  • #61
How compass detect the Earth’s natural magnetic fields, to tell the direction ??
 
  • #62
Xidike said:
How compass detect the Earth’s natural magnetic fields, to tell the direction ??

The same way two magnets detect each other.
 
  • #63
Xidike said:
How compass detect the Earth’s natural magnetic fields, to tell the direction ??

If you won't read that link fully then I don't think you will read any answer I give you. No more spoonfeeding. I'm done.
 
  • #64
Drakkith said:
The same way two magnets detect each other.
Then why the north pole of Earth and north pole of Magnet Does not repel each other.. ?
 
  • #65
Xidike said:
Then why the north pole of Earth and north pole of Magnet Does not repel each other.. ?

Because the North pole of the Earth is actually a magnetic SOUTH pole!
(I'm serious)
I think that poles of magnets were named a certain way because one pole wanted to face North all the time. This requires that the other pole, the Earth's pole, be a south pole. I'd bet that way back in the day when magnetism was first studied, they noticed that one pole wanted to face North all the time so they labeled the Earth's pole a NORTH pole since it was in the North, and ignored the fact that the Magnetic pole was actually a magnetic SOUTH pole.
 
  • #66
Ahhh. I see your problem and the confusion. The following can be found on the net - I have read it but people don't always bother to make it clear. It confused me at School when I was first taught about magnets. I think many people don't even worry about it at all.

The Correct Name for the 'North Pole' that is marked a magnet is actually a 'North Seeking Pole'. This means it will point to the Earth's North Pole. So this means (annoyingly and confusingly!) that, at the Earth's North Pole, there must be a South Seeking Pole - because that will follow the attraction / repulsion rules for magnets in general!
 
  • #68
Is there any condition when Earth And Magnet Repel Each others ??
 
  • #69
Xidike said:
Is there any condition when Earth And Magnet Repel Each others ??

Sure, turn the south pole to the north. You have repulsion. It's just REALLY weak.
 
  • #70
I tried but it does not work for me..
 

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