I have a ? and I hope someone can help me with the answer.
Strong magnetic fields may best be established in a core made of.
choices are air, steel, nickel, or cobalt. :blink:

 

hi susie,

am not sure how to answer your query. each of those mediums have their own strenght and weaknesses depending on the application. there are apllication where you don't need strong magnetic field.

 

hi
the strength of magnetic field depends on the permeability of the material.greater the permeability,greater the strength of the field.it goes in the order
nickel=~cobalt > steel > air

 

Most common core in AC Machines is steel with laminated silcon inbetween sheets.
This is done to reduce eddy currents and give a better hysterises curve (as air does not get magnetically saturated)