Question

An electron of mass m and charge e is accelerating from rest through a potential difference v in vacuum it's final speed will be

Answer 1

energy gained by electron when it passes through potential difference of V volt is eV now this energy will converted to kinetic energy and kinetic energy is equal to 1/2×mv^2

equating it with the the given energy

1/2×mv^2 = eV

v=(2eV/m)^2