
65,000 magnetic field lines per square inch. now, 1gauss is about 6.5 magnetic field lines per square inch. if you place the tip of your index finger to the tip of your thumb, enclosing approximately 1 square inch, four magnetic field lines would pass through that hole due to the earths magnetic field measuring the strength of magnets. 1.,strong magnetic field safety signs from,restricted access strong magnetic field this magnet is always on discuss any of the following with the mri technologist or radiologist before entering this area 1) any metallic, electronic or magnetic implants or devices in your body 2) if you have been exposed to metal shavings from operations like grinding or sawing as part of your occupation 3) if you have metal embedded in