To shield an object from a magnetic field you can place it within a conducting container, such as an iron box/ring. The field lines will not penetrate the conductor.Probably a silly question, but why is this - i know that the obvious answer is that its a conductor - but what is the mechanism that causes this to happen. Where does the energy of the field go, as no current will be induced in the conductor unless there is a change in flux, so does it simply create a potential within the conductor?
Magnetic shielding can only be achieved with metals that are themselves magnetic (eg iron) - copper, aluminium, zinc etc do not work The magnetic flux is 'drawn into' the iron because materials like iron provide an 'easier' pathway for the flux (or 'field lines') than air This behaviour is due to the existence of magnetic domains within ferromagnetic materials that align themselves with the magnet's field. Magnetic permeability is used as a measure of a materials ability to support the formation of a magnetic field - iron has a value that is about 700 times better than air. The magnetic field within the iron isn't destroyed.
