Answer to Question #139712 in Electricity and Magnetism for Cameron Hicks

Question

Is there a formula to work out the necessary magnetic field strength with which to move a varying weight of different metals? Can this equation also be manipulated to show the strength needed in fresh and salt water?

Answer 1

Unfortunately, there is no such equation because the magnetic force between an electromagnet and a piece of metal depends on the magnetic properties and shape of the piece. Experiments are needed to establish the value of field for each piece. Moreover, no equation cannot be manipulated to find the field necessary to extract dissolved metals from sea water because they are represented by very small dust that cannot be attracted to a magnet.