How does a magnetic field cause electric charges to form an electric current? O A. A force is exerted by the magnetic field on only the positive charges in the wire. B. Negative charges and positive charges are pushed in opposite directions by the magnetic field. C. A force is exerted by the magnetic field on only the negative charges in the wire. D. Negative charges and positive charges are pushed in the same direction by the magnetic field.

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.