First of all, we need to calculate the magnetic field generated by the wire at a distance r=3.90 cm=0.039 m, which is given by:

where I=8.60 A is the current. Substituting numbers in the equation, we find

And now we can calculate the force exerted on the electron, which is given by:

where
is the charge of the electron and
is its speed. Substituting data in the formula, we find
