Magnetic Screening

This is a way of protecting delicate instruments which are affected by magnetic fields. Magnetic lines of force tend to crowd into a soft iron ring. The lines pass through the ring and do not cross into the space inside. In this way, the space or the instrument is shielded or screened from the effect of the magnetic field.

CathodeA cathode is the electrode from which a conventional current leaves the electrolyte. It is the negative part of the cell where reduction takes place. More ray tubes are also protected from magnetic fields using magnetic screening.