Question

describe what happens to the magnetic field surrounding a current-carrying wire if the current is reversed?

Answer 1

A current carrying conductor produces a region of magnetic field around it. The magnitude of this field is directly proportional to the current and inversely proportional to the distance from the wire.

The direction of magnetic field is given by the right hand thumb rule. In thumbs up position, place the thumb in the direction of current, the the direction in which other fingers curl gives the direction of the magnetic field.

Now reversing the current without any change for other parameters will simply reverses the direction of magnetic field. Means a north pole becomes a south pole and vice versa.