In a magnetic crane, a powerful electromagnet is used to lift up the iron material. But when we pass a current through a conductor & bring iron filings near it, they are set in a form of concentric circles, instead of clinging to the conductor. Why? In a magnetic crane, a powerful electromagnet is used to lift up the iron material. But when we pass a current through a conductor & bring iron filings near it, they are set in a concentric manner, instead of clinging the conductor. Why?