Are 2 bar magnets stuck together, twice as strong?

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Discussion Overview

The discussion revolves around whether two bar magnets stuck together can create a magnetic field that is approximately twice as strong. Participants explore the implications of magnetic field strength, flux density, and the arrangement of magnets in various contexts, including practical applications and theoretical considerations.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants argue that while the magnetic field may become stronger at certain points, it will not double in strength overall, suggesting that two magnets create a larger magnet rather than a stronger one.
  • Others propose that the ability of two magnets to lift a weight could effectively double, even if the magnetic field strength does not change, indicating a distinction between magnetic field strength and practical lifting capacity.
  • One participant questions why the fields do not add together like vectors to form double the flux density, drawing a comparison to electric charges.
  • Another response suggests that the flux density could indeed be higher depending on the arrangement of the magnets, though it notes that the fields would not be at the same point, which complicates the comparison.
  • A participant acknowledges conflicting opinions, noting that some assert no change in flux density while others claim there will be an increase.
  • One participant mentions that the peak magnetic field strength may not change significantly, but the magnetic field strength at a distance could nearly double, indicating that the context of measurement matters.
  • Another participant elaborates that the field strength could potentially decrease under certain conditions, providing a mathematical expression to illustrate this point.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the relationship between the arrangement of magnets and the resulting magnetic field strength and flux density. The discussion remains unresolved, with no consensus reached on whether two bar magnets can create a magnetic field that is twice as strong.

Contextual Notes

Participants highlight the importance of context in measuring magnetic field strength and flux density, noting that different arrangements and distances from the magnets can yield varying results. There are also references to mathematical calculations that could clarify the relationship between magnet size and field strength.

pkc111
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Can 2 bar magnets be stuck together to create a magnetic field about twice as strong?
 
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No. It can get stronger at some points, depending on the arrangement, but it won't get twice as strong anywhere. You mainly create a larger magnet.
 
pkc111 said:
Can 2 bar magnets be stuck together to create a magnetic field about twice as strong?
It depends what you mean by "strong" and what the application happens to be. If one magnet will lift a 1kg block then two magnets, side by side, will very likely be able to lift 2kg. But the Magnetic Field may not change. What can happen is that the magnetic Flux Density will act over twice the area, giving twice the Flux acting on the block.
 
Why don't the fields add together like vectors and form double the flux density? Like 2 charges at the same point do in an electric field.
 
pkc111 said:
Why don't the fields add together like vectors and form double the flux density? Like 2 charges at the same point do in an electric field.
It can be double the flux or more flux density over the same area, depending on the patterns of the fields over the ends of the individual magnets. The "charges" you refer to would not be at exactly the same point (infinite repulsive force) but, just as with the magnetic poles, the effect would be spread out. At a reasonable distance was, the fields would be double.
 
There are conflicting opinions here...2 say no change in flux density...1 says there will be..Any more opinions please? With a reference please
 
This link could help you, I think. Do the calculation for a particular width W and then for 2W. Equating two magnets to one wide magnet would be a reasonable thing to do.
 
The peak magnetic field strength won't change much, the magnetic field strength far away can nearly double.

There is no conflict between the statements, they just apply to different places.
 
mfb said:
The peak magnetic field strength won't change much, the magnetic field strength far away can nearly double.

There is no conflict between the statements, they just apply to different places.

The field strength can even go down. If you take the field strength on the axis of a cylindrical magnet, with thickness 1, at a distance of 1 and with radius R, this will have a maximum for R ≈ 2.066. The contribution of the extra material at the edge of the magnet wil become negative if the radius is larger than that.

If you type in 1/2*((D+z)/sqrt(R**2+(D+z)**2) - z/sqrt(R**2+z**2)), D=1, z=1 in wolfram alpha you can click on the result with only R as a variable to make a plot and compute the minima/maxima.
https://www.wolframalpha.com/input/...=1&rawformassumption="ClashPrefs"+->+{"Math"}.
 

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