What effect does reversing the direction of current flow have on an current carry wire in a magnetic field?

Reversing the direction of current flow in a current-carrying wire in a magnetic field will cause the wire to experience a force in the opposite direction. This is due to the right-hand rule, which states that the direction of the force on a current-carrying wire in a magnetic field is perpendicular to both the direction of the current and the magnetic field. Therefore, reversing the direction of current flow will result in a force acting in the opposite direction on the wire.

Reversing the direction of current flow in a current-carrying wire in a magnetic field reverses the direction of the magnetic force acting on the wire and the direction of the torque that tends to rotate the wire.

Mathematically:

Force: F = ILB (original direction)
F = -ILB (reversed direction)

Torque: τ = ILB(r) (original direction)
τ = -ILB(r) (reversed direction)

Where:

F is the magnetic force on the wire
I is the current flowing through the wire
L is the length of the wire in the magnetic field
B is the magnetic field strength
τ is the torque on the wire
r is the distance from the pivot point to the wire

Therefore, if the current direction is changed, the magnetic force and torque on the wire also change direction, causing the wire to move or rotate in the opposite direction.