Experiments carried out on the television show Mythbusters determined that a magnetic field of 1000 gauss is needed to corrupt the information on a credit card's magnetic strip. (They also busted the myth that a credit card can be demagnetized by an electric eel or an eelskin wallet.) Suppose a long, straight wire carries a current of 2.5 A. How close can a credit card be held to this wire without damaging its magnetic strip?
I'm not quite sure how to go about this problem, could anyone please explain it?
Magnetic field of a solenoid:
The Attempt at a Solution