question_answer 42)

  In an adiabatic process, no transfer of heat takes place between system and surroundings. Choose the correct option for free expansion of an ideal gas under adiabatic condition from the following : (a) \[q=0,\Delta T\ne 0,w=0\]                                                    (b)\[q\ne 0,\Delta T=0,w=0\] (c) \[q=0,\Delta T=0,w=0\]                                                          (d) \[q=0,\Delta T<0,w\ne 0\]

Answer:

  (c) For, free expansion,  \[w=0\] For, adiabatic process, \[q=0\] From first law of thermodynamics: \[\Delta U=q+w\] \[=0+0=0\] Since, there is no change of internal energy hence temperature will also remain constant, i.e.,\[\Delta T=0\]