1.

If the boundary of system moves by an infinitesimal amount, the work involved is given by `dw=-P_("ext")dV` for irreversible process `w=-P_("ext")DeltaV " "( "where "DeltaV=V_(f)-V_(i))` for reversible process `P_("ext")=P_("int")pmdP~=P_("int")` so for reversible isothermal process `w = -nRTln.(V_(f))/(V_(i))` 2mole of an ideal gas undergoes isothermal compression along three different plaths : (i) reversible compression from `P_(i)=2` bar and `V_(i) = 8L` to `P_(f) = 20` bar (ii) a single stage compression against a constant external pressure of 20 bar, and (iii) a two stage compression consisting initially of compression against a constant external pressure of 10 bar until `P_("gas")=P_("ext")`, followed by compression against a constant pressure of 20 bar until `P_("gas") = P_("ext")` Total work done on the gas in two stage compression is :A. 40B. 80C. 160D. None of these

Answer» Correct Answer - B
`w_("irr (total)")=w_(1)+w_(2)`
`=-10((nRT)/(10)-(nRT)/(2))`
`=-20((nRT)/(20)-(nRT)/(10))`
`=5xxnRT=80 " bar-L"`


Discussion

No Comment Found

Related InterviewSolutions