5. In an open system, for maximum work, the process must be entirely a) irreversible
b) reversible
c) adiabatic
d) none of the mentioned
7. Which of the following is true for a closed system?
a) mass entering = mass leaving
b) mass does not enter or leave the system
c) mass entering can be more or less than the mass leaving
d) none of the mentioned
13. A piston cylinder contains 0.5 kg of air at 500 kPa and 500 K. The air expands in a
process so pressure is linearly decreasing with volume to a final state of 100 kPa and 300
K. Find the work in the process.
a) 56.1 kJ
b) 66.1 kJ
c) 76.1 kJ
d) 86.1 kJ
5- И
Land 279 At this state the