physics chap15

• Adiabatic process


  A process in which no heat transfer takes place
• Carnot cycle


  A cyclical process that uses only reversible processes, the adiabatic and isothermal processes
• Carnot efficiency


  The maximum theoretical efficiency for a heat engine
• Carnot engine


  A heat engine that uses a Carnot cycle
• Change in entropy


  The ratio of heat transfer to temperature Q/t
• Coefficient of performance


  For a heat pump, it is the ratio of heat transfer at the output (the hot reservoir) to the work supplied; for a refrigerator or air conditioner, it is the ratio of heat transfer from the cold reservoir to the work supplied
• Cyclical process


  A process in which the path returns to its original state at the end of every cycle
• Entropy


  A measurement of a system's disorder and its inability to do work in a system
• First law of thermodynamics


  States that the change in internal energy of a system equals the net heat transfer into the system minus the net work done by the system
• Heat engine


  A machine that uses heat transfer to do work
• Heat pump


  A machine that generates heat transfer from cold to hot
• Human metabolism


  Conversion of food into heat transfer, work, and stored fat
• Internal energy


  The sum of the kinetic and potential energies of a system's atoms and molecules
• Irreversible process


  Any process that depends on path direction
• Isobaric process


  Constant-pressure process in which a gas does work
• Isochoric process


  A constant-volume process
• Isothermal process


  A constant-temperature process
• Macrostate


  An overall property of a system
• Microstate


  Each sequence within a larger macrostate
• Otto cycle


  A thermodynamic cycle, consisting of a pair of adiabatic processes and a pair of isochoric processes, that converts heat into work, e.g., the four-stroke engine cycle of intake, compression, ignition, and exhaust
• Reversible process


  A process in which both the heat engine system and the external environment theoretically can be returned to their original states
• Second law of thermodynamics


  Heat transfer flows from a hotter to a cooler object, never the reverse, and some heat energy in any process is lost to available work in a cyclical process
• Second law of thermodynamics stated in terms of entropy


  The total entropy of a system either increases or remains constant; it never decreases
• Statistical analysis


  Using statistics to examine data, such as counting microstates and macrostate