Question

A cylinder containing an ideal gas ( see figure ) and closed by a movable pistong is submerged in an ice- water mixture. The pistone is quickly pushed down from position (1) to position (2)( process `AB)`. The piston is held at position `(2)` until the gas is again at `0^(@)C` ( processs `BC)`. Then the pistone is slowly raised back to position (1) ( process `CA)`

Which of the following `P-V` diagram will correctly represent the processes `AB, BC` and `CA` and the cycle `ABCA?`
A. `8 kcal`
B. `5 kcal`
C. `2.1 kJ`
D. `4.2kJ`

Answer 1

Correct Answer - A
If `Delta W` is the work done in the whole cycle, we have
`DeltaQ=DeltaW+DeltaU`
But `DeltaU=0` for the entire cycle.
Hence `Delta W=DeltaQ=mL`
`=100xx80=8000cal =8 k cal`