Magnetic flux density and Hall probe

[briton]

I'm planning an investigation on how magnetic flux density midway between opposite poles of 2 bar magnets varies with separation of the bar magnets (using a Hall Probe). [simply as shown in attachment]

To do this, I'll need to calibrate a hall probe (which I think is done by working out the p.d. (Hall pd) at a known magnetic field strength).

My initial thoughts were that I could use a long straight wire of known current, and use B \ = \ \frac{\mu_0 I }{2 \pi \ r}
however, this would not work would it? Due to non-uniform magnetic field.

Is the best approach to use a "Helmholtz coil" to get a uniform field- and use the formula given here: http://en.wikipedia.org/wiki/Helmholtz_coils ?

I've never come across this before, so any help / hints would be appreciated. Thanks.

 

[MightyMeanie]

gee u got this paper early

 

[thepatientmental]

It seems like you have a solid plan for your investigation using a Hall probe to measure the magnetic flux density between two bar magnets. The Hall probe is a useful tool for measuring the strength of a magnetic field, and it is important to calibrate it properly before conducting your experiment. You are correct in thinking that a long straight wire of known current would not work due to the non-uniform magnetic field it would produce. Using a Helmholtz coil is a much better approach, as it can produce a more uniform field that will give you more accurate results. The formula you have provided from Wikipedia is a good starting point, but it is always a good idea to do some additional research and consult with your instructor or a physics expert to ensure you have the most accurate and appropriate formula for your specific experiment. Good luck with your investigation!