Electron-volts
An electron-volt (eV) is used in the fields of atomic and particle physics. It is the amount of energy gained or lost by a single electron when it is accelerated through an electric potential difference of one volt.
Calories (Kilogram,I.T.)
The kilogram calorie is often referred to as the kilocalorie or Calorie with an uppercase 'C'). It is defined as the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius at one atmosphere of pressure.