In physics, energy is ane o the basic quantitative properties describin a physical seestem or object's state. Energy can be transformed (convertit) amang a nummer o furms that mey each manifest an be measurable in differin ways. The law o conservation o energy states that the (tot) energy o a seestem can increase or decrease anly bi transferrin it in or oot o the seestem. The tot energy o a seestem can be calculatit bi simple addeetion when it is componed o multiple non-interactin pairts or haes multiple distinct furms o energy. Common energy furms include the kinetic energy o a movin object, the radiant energy carried bi licht an ither electromagnetic radiation, an various types o potential energy such as gravitational an elastic. Energy is measured in SI units o joules (J). Common types o energy transfer an transformation include processes such as heatin a material, performin mechanical work on an object, generatin or makin uise o electric energy, an mony chemical reactions.

Energy transformation; In a typical lichtnin strike, 500 megajoules o electric potential energy is converted intae the same amoont o energy in ither furms, maist notably licht energy, soond energy an thermal energy.