posted by mohab .
A long solenoid ( radius = 1.4 cm) has a current of a 0.34 A in its winding. A long wire carrying a current of 18 A is parallel to and 1.2 cm from the axis of the solenoid. What is the magnitude of the resulting magnetic field at a point on the axis of the solenoid?
(Hint: What are the directions of the B fields created by the solenoid and the wire?)
B fields are perpendicular.
So figure each, then add as vectors.