question_answer 28)

                  Two charged particles traverse identical helical paths in a completely opposite sense in a uniform magnetic field . (a) They have equal z-components of momenta (b) They must have equal charges (c) They necessarily represent a particle-anti- particle pair (d) The charge to mass ratio satisfy :

Answer:

                 (d)In a uniform magnetic field, the two charged particles will traverse identical helical paths in a completely opposite sense if the charge/mass ratio of these two particles is same and charges on them are of opposite character. In this situation = 0, holds good.