Hence , it is the base SI representation m2 Â kg Â s-3 Â A-1 , which can be equally represented as one joule of energy per coulomb of charge , J\/C . It can be written in terms of SI base units as : m2 Â kg Â sâ ' 3 Â Aâ ' 1 . It is also equal to one joule of energy per coulomb of charge , J\/C .