InterviewSolution
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InterviewSolution
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The reversible expansion of an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct? A. `T_(1)=T_(2)`B. `T_(3)gtT_(1)`C. `w_("isothermal")gtw_("adiabatic")`D. `DeltaU_("isothermal")gtDeltaU_("adiabatic")` |
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Answer» Correct Answer - A::D For isothermal expansion, `DeltaT=`constant i.e. `T_(1)=T_(2)` at const temperature, internal energy `(DeltaU)` of the system remains constant i.e., `DeltaU_("isothermal")=0` Reversible expansion work=`-2.303nRT"log"(V_(2))/(V_(1))` In adiabatic expansion, no heat is allowed to enter `w` is leave the system, hence `q = 0` `DeltaE=q+w. :. q = 0` `DeltaE=w` In expansion, work is doen by the system, hence `w` is negative, accordingly, `DeltaE=-ve`, i.e., Internal energy decrease and therefore the temperature of the system falls. Thus, `T_(3) lt T_(1)` Thus, `DeltaU_("adiabatic")=-ve` Thus, `DeltaU_("Isothermal") gt DeltaU_("adiabatic")` `w_("adiabatic")=R/((gamma-1))(T_(2)-T_(1))` Thus, Including sign, `w_("isothermal") lt w_("adiabatic")` |
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