A perfectgasundergoesthe followingthreeseparateand distinctprocessto executea cycle. (I )constantvolumeprocesswhich80 KJof heatis suppliedto thegas(ii)constantpressureprocessduringwhich85 KJof heatis lostto thesurroundingand 20KJof workis doneon it . (iii)adiabaticprocesswhich restores the gasbackto itsintitalstate . Evaluate the workdoneduringadiabaticand thevalueof internalenergyat allthe statepointsif initiallyits valueis 95 KJ .

A perfectgasundergoesthe followingthreeseparateand distinctprocessto e

1.	A perfectgasundergoesthe followingthreeseparateand distinctprocessto executea cycle. (I )constantvolumeprocesswhich80 KJof heatis suppliedto thegas(ii)constantpressureprocessduringwhich85 KJof heatis lostto thesurroundingand 20KJof workis doneon it . (iii)adiabaticprocesswhich restores the gasbackto itsintitalstate . Evaluate the workdoneduringadiabaticand thevalueof internalenergyat allthe statepointsif initiallyits valueis 95 KJ .
Answer» Solution :Thisexampleillustratesthe applicationof non - flowenergyequationand the1 stlawappliedto acyclicprocess process1-2`Q_(1-2) = 80KJ, W_(1-2) =0` , ` U_2-U_1= Q_(1-2) - W_(1-2) = 80 -0 = 80 KJ` `thereforeU_2 = 80 + 95 =175KJ` process2-3: `Q_(2-3)=- 85KJ , W_( 2-3) =- 20 KJ` ` thereforeU_3 =- 65+ 175= 110KJ` forthecompletecycle` ointdeltaQ=ointdelta w ` that is `Q_(1-2)+Q_(2-3)+Q_(3-1)= W_(1-2) +W_(2-3) +W_(3-1)` `80-85 + 0 =0 +(-20) +W_(3-1)` ` therefore `workdoneduringadiabaticprocess `W_( 3-1)= 15 KJ`