Measuring change of magnetic field strengh over distance

Click For Summary

Discussion Overview

The discussion revolves around measuring or calculating the magnetic induction of cylindrical neodymium magnets at a specific distance from their center. Participants explore methods for both measurement and calculation, addressing the complexities involved in accurately determining magnetic fields.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant inquires about the equation needed to calculate magnetic induction at a distance from the center of a neodymium magnet, expressing a lack of knowledge about magnets.
  • Another participant suggests using a Hall probe for measurement, noting the challenges of using another magnet for this purpose.
  • Some participants emphasize the difficulty of calculating magnetic fields, indicating that it is typically solved numerically and may not be suitable for those unfamiliar with the topic.
  • A participant mentions their engineering thesis on superparamagnetic iron oxide nanoparticles (SPION) and seeks to calculate the magnetic field strength needed from neodymium magnets.
  • There are references to smartphone apps for measuring magnetic fields, but concerns are raised about their effectiveness near strong magnets.
  • One participant claims to have found an answer using an online calculator and suggests closing the thread.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of calculating magnetic induction without advanced tools or knowledge. While some suggest measurement as a more practical approach, others discuss the complexities of the calculations involved. The discussion remains unresolved regarding the best method to achieve the desired results.

Contextual Notes

Participants note the lack of adequately specified boundary conditions for the calculations, which may affect the accuracy of any proposed methods. There are also concerns about the limitations of smartphone apps in measuring strong magnetic fields.

april7
Messages
4
Reaction score
0
I have few cylindrical neodymium magnets of same diameter and different heights and different magnetic inductions in the geometric center of the magnetic pole surface. Knowing those values of magnetic induction, how can I measure what the induction is at a certain distance from that center?

For example height: 4 [mm] and induction: 0,263 [T]
What equation do I use to know what the induction is at distance of 4mm? I'm very much clueless about magnets and don't really know where to look.
 
Physics news on Phys.org
Get a Hall probe.

Trying to measure the field with another magbet is difficult, as each pole responds differently, and what you will see is the difference in the field between the two. Converting that to a field is non-trivial.
 
april7 said:
I have few cylindrical neodymium magnets of same diameter and different heights and different magnetic inductions in the geometric center of the magnetic pole surface. Knowing those values of magnetic induction, how can I measure what the induction is at a certain distance from that center?

For example height: 4 [mm] and induction: 0,263 [T]
What equation do I use to know what the induction is at distance of 4mm? I'm very much clueless about magnets and don't really know where to look.
Do you want to measure the magnetic field or calculate it? If you are "very much clueless about magnets" I suggest that you buy a magnetometer and measure it. There are apps for smartphones but I am not sure of their limitations for strong magnetic fields like yours. Also, bringing a neodymium magnet close to your smartphone might mess up its compass calibration or other "stuff".
 
Last edited:
kuruman said:
Do you want to measure the magnetic field or calculate it? If you are "very much clueless about magnets" I suggest that you buy a magnetometer and measure it. There are apps for smartphones but I am not sure of their limitations for strong magnetic fields like yours. Also, bringing a neodymium magnet close to your smartphone might mess up its compass calibration or other "stuff".
Yes, I haven't specified it but I need to calculate it
 
april7 said:
I need to calculate it
april7 said:
I'm very much clueless about magnets
Those two statements are mutually inconsistent.

What you want is very difficult and usually solved numerically. It is not for the clueless, I'm afraid,
 
Vanadium 50 said:
Those two statements are mutually inconsistent.

What you want is very difficult and usually solved numerically. It is not for the clueless, I'm afraid,
I'm doing my engineering thesis on superparamagnetic iron oxide nanoparticles (SPION) and I'm tasked with creating a model of magnetic pad we will use to stimulate particles with. I have to calculate which of few different neodymium magnets will give approximate value of 200 mT at distance of 4 mm. I want to know if I can calculate it and how I can do that without using programs.
 
Again, this is really hard. You don't even have adequately specified boundary conditions. As people have suggested, measure.
 
well I used chatgpt, asked same question and was directed to online calculator and softwares that can calculate it
I've got my answer now so I guess thread can be closed
 
Good luck.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 42 ·
2
Replies
42
Views
3K
  • · Replies 1 ·
Replies
1
Views
951
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 15 ·
Replies
15
Views
3K