Answer:
The magnetic field is lowest for largest distance and highest when distance is least.
Explanation:
The magnitude of magnetic field strength at a distance 'r' from a long straight wire carrying current 'I' is given as:

Now, as per question, the distance 'r' is varied while keeping the current constant in the wire.
As seen from the above formula, the magnitude of magnetic field strength for a constant current varies inversely with the distance 'r'. This means that, as the value of 'r' increases, the magnitude of magnetic field strength decreases and vice-versa.
Therefore, the magnitude of magnetic field strength is maximum when the distance 'r' is least and the magnetic field is minimum for the largest distance.
Example:
If
are the magnitudes of magnetic field strengths for distances
respectively such that
. Now, as per the explanation above, the order of magnitudes of magnetic field strength is:
