A thermal engine having three moles of monoatomic gas as its working fluid undergoes the cyclic process shown in Figure 3.87 (a $P$ - $T$ graph). Find the mechanical work over one cycle approximately ( $R = 8.314$ J $m o l^{- 1}$ $K^{- 1}$ ):

Question

TestHub · Accepted Answer

1 → 2 and 3 → 4 are lines through the origin (isochoric); 2 → 3 and 4 → 1 are isobaric. W = n R [ ( T 3 ​ − T 2 ​ ) − ( T 4 ​ − T 1 ​ ) ] = 3 × 8.314 × [ ( 2400 − 800 ) − ( 1200 − 400 ) ] = 3 × 8.314 × 800 = 19954 J, about 20 kJ. C.

Physics - Heat & Thermo Question with Solution | TestHub

Options:

Doubts & Discussion