The expression
for the magnetic field of a straight wire provides a theoretical
justification to Oersted’s experiments (iii)
Another interesting point to note is that even though the wire is
infinite, the field due to it at a non-zero distance is not infinite It
tends to blow up only when we come very close to the wire The
field is directly proportional to the current and inversely
proportional to the distance from the (infinitely long) current source