The enrgy is always lost or gained in only the definite amount that is called as discrete or packet energy.
radiation balance
Albert Einstein proposed that light is made up of discrete packets of energy, which he called "quanta." This theory helped to lay the foundation for the development of quantum mechanics.
When the amount of energy received from the sun and the amount of energy returned to space are about equal, it is called energy balance or radiative equilibrium. This balance helps maintain the Earth's overall temperature and climate.
radiation balance
radiation balance
The amount of available energy that can be used to promote change and do work is called free energy. This is the energy that is available to do useful work in a system.
This energy is the activation energy.
A quantum of energy is the amount of energy required to move an electron from one energy level to another energy level. http://www.slideshare.net/kmawhiney/electrons-in-atoms-presentation/
The average amount of energy of motion of each particle of a substance is called kinetic energy. It is related to the speed and mass of the particles.
The amount of energy available to do work after a chemical reaction has occurred is called free energy or Gibbs free energy. It represents the maximum amount of useful work that can be obtained from a system at constant temperature and pressure.
The total amount of energy in an object is called energy, regardless of its form (heat, thermal, electrical, etc.).