2. a mass of absorbing material; for example, concrete or lead, placed around a reactor or radioactive material to reduce the radiation to a level safe for humans.
Electromagnetic fields are caused by motors, generators, relays, or devices whose operation dempends on alternating fields.
Shielding is achieved by a reflection or absorption of fields while reflection occurs at the surface, and it is not usually affected by shield thickness.
Absorption, however, occurs within the shield and it is highly dependent on the thickness of the shield.
2. A metallic enclosure or screen placed around an apparatus so it will not be affected by external electric fields.
3. A grounded metal screen, sheet, or enclosure placed around an apparatus or between two appliances to prevent electric fields from acting through the shield.
It can prevent interaction between the electric fields of adjacent parts on a chassis.
Some experts claim that the manufacture of various chemicals; such as, chlorofluorocarbons used as propellants in aerosol sprays, and the effects of high-flying jet aircraft are destroying this protective layer and allowing excessive amounts of ultraviolet radiation to penetrate the earth's atmosphere; therefore, subjecting humans to increased dangers of skin cancer and other health problems.