Which would you sprinkle around the electromagnet that you produced in the laboratory activity to see its magnet
field lines?
which would you use to determine the direction of the field lines around a magnet?
which would you use with a circuit to determine if a magnet was moving in close proximity to the
circuit?

An alpha particle with kinetic energy 12.5 mev makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude l = p0 b, where p0 is the magnitude of the initial momentum of the alpha particle and b=1.40×10−12 m. (assume that the lead nucleus remains stationary and that it may be treated as a point charge. the atomic number of lead is 82. the alpha particle is a helium nucleus, with atomic number 2.) what is the distance of closest approach?