Answer:
e/m for electron is 1/0 (as electron has negligible mass),
for proton is 1/1,
for neutron is 0/1, and for alpha particle is 2/4 or 1/2. (Note that charge unit for e is −1, for proton is +1, for neutron is 0, )
and for alpha particle is +2. The mass unit (amu) for e is almost 0, fro p is 1, for neutron is 1, and for alpha particles is 4.
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