hello guys, I finally decided to join a forum online and starting asking my " brilliant" :-0 questions..hehehe..oh man i have plenty of those.. OK, am reading the book: understanding physics, by isac asimov. And i am reading about magnetisim now, and its stated two things that bugged my simple mind. 1- the book mentioned that a paramagnetic material as a medium ( with big permeability) will actually weakens the force between two poles. ( and it gave an example stating that a bar of iron over both poles of a horse shoe magnet cuts down the magnetic field outside it self to a huge extent) and on the other hand, a diamagnetic material with permeability less than one will increase the magnetic force between poles. is this correct? plz explain :-) 2- it listed the force between two poles as: F= (pole 1 * pole 2) / (permeability * d^2) , with permeability in the denominator, ensuring the above. while in wikipedia ( http://en.wikipedia.org/wiki/Magnet) section 9 its listed with the permeability in the numerator, meaning that the mentioned above in point 1 should be inversed. plz help if u know the answer. i my self will ask around at my university, and see how it goes. ( however this not a course am taking..am actually doing comp eng, i just like reading physics :-) thanks.