a magnet that opeates through electricity is an _____ .unlike ordinary magnets it can be turned on and _____. a simple electromagnet can be made using a _____, _____, and piece of _____. the _____ serves as the core and acts as magnet while electricity is flowing through the coil of wire. when electricity stops flowing through the coil to the nail, it will _____ attracting metals the factors that affects the strength of an electromagnet are the _____. _____, and the _________​