The strength of the magnetic field around a wire is directly proportional to the current flowing through it. This means if you increase the current, you increase the magnetic field strength.

Here's how to figure out the change in magnetic field strength:

* The Ratio: The current increased from 0.25 A to 1.75 A, which is a 7-fold increase (1.75 A / 0.25 A = 7).

* The Result: Since the magnetic field strength is directly proportional to the current, the magnetic field will also become 7 times stronger.

In summary: If you increase the current in a wire from 0.25 A to 1.75 A, the magnetic field around the wire will become 7 times stronger.