Can I calculate magnetic force of a magnet?

[hadroneater]

Is there a way of calculating how much force can be applied to an object if you are given the magnetic field strength of an electromagnetic?

For example, if an electromagnet produces a B field of 4T, what is the maximum mass of iron it can hold?

And also, how does one calculate the magnetic field outside of a solenoid?

*edit* It seems that I may have another question...*sigh*

If I wrap wires around an iron core like a solenoid to make an electromagnet, would its magnetic strength decrease or increase if I increase the radius of the core? How would I maximize the strength other than having more turns of wires?

 

[jerio_angus]

try this address

http://en.wikipedia.org/wiki/Electromagnet it should help u to calculate

the strength which is produce by the magnetic field.

 

[Bob S]

I was working on a 30 ton electromagnet with a 12,000 Gauss (1.2 Tesla) field, and lots of fringe field. A grad student wheeled by a large gas bottle of CO2, which the magnet snatched and broke off the pressure regulator. We could not remove it without turning off the current. If you put an octegenarian on O2 in a 4T MRI (NMR) solenoid, the flying O2 bottle will crush him.

 

[rahil]

To increase the strength of the electromagnet, just, increase the number of winof the solenoid.