How to find the strength of an electromagnet

AI Thread Summary
To find the strength of an electromagnet, the key measurement is magnetic flux density, which can be calculated using the formula T = N/Am. To apply this, measure the current in Amperes with a multimeter and determine the force in Newtons, which may involve using the magnetic permeability of the iron core. The length in the formula refers to the length of the coil wrapped around the iron. For comparing the strength of a permanent magnet, additional methods or tools may be needed to measure its magnetic field strength. Understanding these principles will help in evaluating both electromagnets and permanent magnets effectively.
Pharrahnox
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I have created a simple electromagnet that is just an iron railroad spike with some thick insulated wire wrapped around it. This is connected to a dodgy, old motorbike battery (I'm thinking of being a decent battery...).

I have looked up how you measure the strength, but I'm not sure what is the one I'm looking for. Is it magnetic flux density?

If so, I found the formula for teslas: T = N/Am. How can I apply this to my magnet? I can find the Amperes with a multimeter, but I don't know how to find the Newtons... Also, with the metres part, is that the length of iron wrapped in the coil, or just the length of iron all together?
 
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Ok, thankyou, the link was very helpful.

I'm not sure if I should start a new thread for this or not, but I'm hoping there is an easy answer.
I also have a horse-shoe shaped permanent magnet, and I was wondering how I can figure out its strength, to compare with electromagnets that I will build.
 

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