An electrical current sent through a coil of insulated wire creates a strong magnetic field within the coil. Wrapping the coil around an iron core enhances the magnetic field because iron is not only attracted to magnetic fields but is also easily magnetized. Certain other metals, such as nickel and cobalt, also have these two properties. Some such metals can be permanently magnetized. Others, including iron, lose their magnetism when the magnetic field is removed.
If the electric current described above can be started and stopped by a switch, what would happen if the switch is turned off?The core will
The core described in the paragraph is iron. Iron loses its magnetism when a magnetic field is removed, which in this case would occur when the switch is turned off.