Q: Given a scientific passage and an answer, generate a question for the given answer.
Passage: Magnetic Field Produced by a Current-Carrying Solenoid A solenoid is a long coil of wire (with many turns or loops, as opposed to a flat loop). Because of its shape, the field inside a solenoid can be very uniform, and also very strong. The field just outside the coils is nearly zero. Figure 22.40 shows how the field looks and how its direction is given by RHR-2. Answer: solenoid
A:
What current-carrying long coil of wire acts as a magnet?