Energy transfer can be considered for the special case of systems which are closed to transfers of matter. The portion of the energy which is transferred by conservative forces over a distance is measured as the work the source system does on the receiving system. The portion of the energy which does not do work during the transfer is called heat.[note 4] Energy can be transferred between systems in a variety of ways. Examples include the transmission of electromagnetic energy via photons, physical collisions which transfer kinetic energy,[note 5] and the conductive transfer of thermal energy. COUNT 3
QSN1 What can be considered for the special case of systems which are closed to transfers of matter? ANS1 Energy transfer QSN2 The portion of energy which does not do work during the transfer is called what? ANS2 heat QSN3 Give one example of how energy can be transferred between systems? ANS3 transmission of electromagnetic energy via photons