Megaelectron-volts
A megaelectron-volt (MeV) is a unit of energy used in particle and nuclear physics. It is derived from the electron-volt (eV) - the amount of kinetic energy gained or lost by an electron when it moves through one volt.
Calories (20°C)
A Calorie (20°C) is sometimes referred to as a small calorie or gram calorie. It is a unit of energy defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius from 19.5°C to 20.5°C.