A proton is accelerated through a potential difference of 1V. Its kinetic energy is

a) 1 eV

b) Zero

c) 2 eV

d) 4 eV

If a proton is accelerated from rest through a potential difference of 30 kV, it is given an energy of 30 keV (30,000 eV) and it can break up as many as 6000 of these molecules (30,000 eV ÷ 5 eV per molecule= 6000 molecules).