Answer:
(i) Isothermal expansion. Temperature Remains constant during an isothermal change. As internal energy is a function of temperature only, so it will remain constant during an isothermal change. As \[\Delta T=0,\]so \[\Delta U={{C}_{V}}\Delta T=0.\] (ii) Adiabatic expansion. For an adiabatic change, \[\Delta Q=0,\] so from first law of thermodynamics, \[\Delta Q=\Delta U+\Delta W=0\] or \[\Delta W=-\Delta U\] During expansion, work is done by a gas i.e., \[\Delta W\] is positive. So \[\Delta U\] must be negative. Hence internal energy of a gas decreases during an adiabatic expansion.
You need to login to perform this action.
You will be redirected in
3 sec