2006-09-14 04:44:23 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Not only will electromagnet waves (field) erase the information but any magnetic field such as a refrigerator magnet will erase them. The particles embedded in the strip are iron oxide just like a cassette or old 8 track tape. Floppy disks are also of the same material. With these devices a magnetic field is precisely applied to the information track just before it is re recorded to erase that area.
2006-09-14 05:20:44 · answer #1 · answered by Buffertest 3 · 0⤊ 0⤋
They are not. Light and radio waves are electromagnetic waves and are all around the cards all the time with no problem. It is strong magnetic fields that damage them. That is because the strip on the back that allows a reader to read it when you swipe it is a short strip of magnetic tape. Just like a cassette tape or VHS tape. A strong magnet can erase the information on the strip, but the card is not destroyed. You will no longer be able to swipe it, but the seller can just read the number printed on the front and type it in by hand.
2006-09-14 12:35:05 · answer #2 · answered by campbelp2002 7 · 0⤊ 0⤋
the strip on the back of the cards that is read by machines is magnetic.
2006-09-14 11:58:08 · answer #3 · answered by dan 4 · 0⤊ 0⤋