Consider a current carrying loop of wire. An electron is shotdirectly through loop's center perpendicular to the plane of theloop. What is the trajectory of the electron? Consider only themagnetic force here and no other forces.
Curving away fromthe loop's axis.
Continuing straightwith no speed change.
The electron willcircle around the loop and back through the hoop's center again and again in circular motion.
Continuing straightbut speeding up or slowing down depending on the direciton of the current.