1. Electromagnetic Shield is a partition, can, or box made of magnetic material (iron, steel, or special alloy) enclosing a magnetic component. The magnetic flux generated by the component is confined by the shield, thus preventing interference with external components. Likewise, external magnetic fields are prevented from reaching the component.
2. It is a grounded partition, metal sheet, wire braid, or other barrier that prevents electromagnetic fields from passing through. Commonly used in electronic equipment to prevent ELECTROMAGNETIC INTERFERENCE. Also used in COAXIAL CABLE to confine electromagnetic fields to the transmission line.
See also, Electromagnetic theory of light, Electromagnetic Radiation, Electromagnetic Energy, Electromagnetic Wave