Magnetic field of magnet and its defination

In summary, the website Cool Magnet Man has a gallery of images of magnets with different positions of the poles.
  • #1
sgstudent
739
3
When we consider a magnet, usually we perceive the field lines to come out of the north pole. But since the poles of a magnet is actually just a man-defined thing, so actually the magnetic field doesn't emerge from the north but it's a constant loop. So when i draw the magnetic field of a bar magnet in this position, instinctively i will draw it like this: http://postimage.org/image/yzybv7vrl/full/

However if i invert my magnet then i would draw it like this:http://postimage.org/image/sh5ksynwt/full/

So if i take the north pole to be where the magnetic field emerges from, then the two magnetic field diagrams would be different but in actuality the second image should look similar to the first.

Thus, from this I'm confused about how i should draw my magnetic field diagram. Are there any guidelines so that i will draw the correct ones? Thanks for the help!
 
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  • #2
I hate field lines too - fortunately they're not a very useful thing and you rarely see them being used except as a general indication of a field.

Anyway, the best way to look at is: If you bring a piece of iron near a pole, the pole will induce an opposite pole in the iron nearby. (it doesn't matter if it's a north or south pole)
Then that pole will induce another opposite pole in the iron as far away as it can. If it's a funny shape, it will induce several poles at the farthest points.

Once you've located all the induced poles, you can draw the field lines between them and add in any curves you feel might make it look more smooth.
 
  • #3
AJ Bentley said:
I hate field lines too - fortunately they're not a very useful thing and you rarely see them being used except as a general indication of a field.

Anyway, the best way to look at is: If you bring a piece of iron near a pole, the pole will induce an opposite pole in the iron nearby. (it doesn't matter if it's a north or south pole)
Then that pole will induce another opposite pole in the iron as far away as it can. If it's a funny shape, it will induce several poles at the farthest points.

Once you've located all the induced poles, you can draw the field lines between them and add in any curves you feel might make it look more smooth.

Haha :smile: we share the same pain. Field lines are so unpredictable. Your method really great! Thanks!
 
  • #4
AJ Bentley said:
I hate field lines too - fortunately they're not a very useful thing and you rarely see them being used except as a general indication of a field.

Anyway, the best way to look at is: If you bring a piece of iron near a pole, the pole will induce an opposite pole in the iron nearby. (it doesn't matter if it's a north or south pole)
Then that pole will induce another opposite pole in the iron as far away as it can. If it's a funny shape, it will induce several poles at the farthest points.

Once you've located all the induced poles, you can draw the field lines between them and add in any curves you feel might make it look more smooth.

Hello again. I was thinking about this and i thought what if both of the poles are exposed to the iron bar like this. Then how should i approach it? Should i draw both induced poles and from there draw the magnetic field? Something like this: http://postimage.org/image/5n2feusjf/full/

Thanks for the help!
 
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What is a magnetic field?

A magnetic field is a region around a magnet or electric current where magnetic forces can be observed. It is represented by a series of lines, called magnetic field lines, that show the direction of the magnetic force at any given point.

What causes a magnetic field?

A magnetic field is caused by the movement of electric charges, such as electrons. In a magnet, the electrons are aligned in the same direction, creating a strong magnetic field. In an electric current, the moving electrons also create a magnetic field.

How is the strength of a magnetic field measured?

The strength of a magnetic field is measured by its magnetic flux density, which is typically represented by the symbol B. It is measured in units of tesla (T) or gauss (G). The higher the magnetic flux density, the stronger the magnetic field.

How does a magnetic field interact with other magnets or objects?

A magnetic field interacts with other magnets or objects in a few different ways. Two magnets with opposite poles will attract each other, while two magnets with the same poles will repel each other. A magnetic field can also exert a force on magnetic materials, such as iron, causing them to be attracted to the magnet.

What are the practical applications of magnetic fields?

Magnetic fields have a wide range of practical applications, including in motors, generators, and transformers. They are also used in various medical imaging techniques, such as MRI machines, and in data storage devices like hard drives. Magnetic fields also play a crucial role in Earth's magnetic field, which protects us from harmful solar radiation.

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