Question

An electron has a total energy of 2MeV.Calculate the effective mass of the electron in Kg and its speed .Assume rest mass of electron 0.511MeV

Answer 1

Mass of electron in Motion =2931amu

⇒2931×1.66×10−27kg

1amu=931MeV

⇒35.6×10−31kg

Also Me=m0e1−(vc)2−−−−−−−−√

35.6×10−31=0.511931×1.66×10−271−[u3×1010]2−−−−−−−−−−√

u=2.9×1010cm/s