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This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.
1. |
Find the specific reversible work for a R-134a compressor with inlet state of 20 C, 100 kPa and an exit state of 600 kPa, 50 C. Use a 25 C ambient temperature. |
A. | 48.878 kJ/kg |
B. | -38.878 kJ/kg |
C. | 48.878 kJ/kg |
D. | -38.878 kJ/kg |
Answer» C. 48.878 kJ/kg | |
2. |
Air in a piston/cylinder arrangement is at 25 C, 110 kPa with a volume of 50 L. It goes through a reversible polytropic process to final state of 500 K, 700 kPa and exchanges heat with the ambient at 25 C. Find the total work from the ambient. |
A. | -9.28 kJ |
B. | -9.38 kJ |
C. | -9.48 kJ |
D. | -9.58 kJ |
Answer» E. | |
3. |
A wooden bucket(2 kg) with 10 kg hot liquid water, both at 85 C, is lowered down to 400 m into a mineshaft. What is the availability of water and bucket with respect to the surface with ambient temperature of 20 C? |
A. | 232.2 kJ |
B. | 242.2 kJ |
C. | 212.2 kJ |
D. | 252.2 kJ |
Answer» B. 242.2 kJ | |
4. |
R-12 at 30 C, 0.75 MPa enters a steady flow device and exits at 30 C, 100 kPa. Assuming the process to be isothermal and reversible, find the change in availability of the refrigerant. |
A. | -26.1 kJ/kg |
B. | -36.1 kJ/kg |
C. | -46.1 kJ/kg |
D. | -56.1 kJ/kg |
Answer» C. -46.1 kJ/kg | |
5. |
Nitrogen is flowing in a pipe with a of velocity 300 m/s at 500 kPa, 300 C. What is its availability relative to an ambient at 100 kPa, 20 C? |
A. | 272 kJ/kg |
B. | 252 kJ/kg |
C. | 292 kJ/kg |
D. | 232 kJ/kg |
Answer» B. 252 kJ/kg | |
6. |
Cold water is running in a river at 2 C and the air temperature is 20 C. What is the availability of water relative to the ambient temperature? |
A. | 2.157 kJ/kg |
B. | 2.857 kJ/kg |
C. | 3.457 kJ/kg |
D. | 2.457 kJ/kg |
Answer» E. | |
7. |
A steady stream of R-22 at ambient temperature of 10 C, and at 750 kPa enters a solar collector. The stream exits at 80 C, 700 kPa. Calculate the change in availability. |
A. | 4.237 kJ/kg |
B. | 5.237 kJ/kg |
C. | 6.237 kJ/kg |
D. | 7.237 kJ/kg |
Answer» D. 7.237 kJ/kg | |
8. |
Find the specific reversible work for a compressor using R-134a with inlet state of 20 C, 100 kPa and an exit state of 50 C, 600 kPa. Use 25 C as ambient temperature. |
A. | -28.878 kJ/kg |
B. | -38.878 kJ/kg |
C. | -48.878 kJ/kg |
D. | -58.878 kJ/kg |
Answer» C. -48.878 kJ/kg | |
9. |
Find the specific reversible work for a steam turbine with inlet at 4 MPa, 500 C and an actual exit state of 100 kPa, x = 1.0 with a 25 C ambient temperature. |
A. | 550.0 kJ/kg |
B. | 650.0 kJ/kg |
C. | 750.0 kJ/kg |
D. | 850.0 kJ/kg |
Answer» E. | |
10. |
The compressor in a refrigerator takes R-134a in at 100 kPa, 20 C and then compresses it to 1 MPa, 40 C. With the room temperature at 20 C find the minimum compressor work. |
A. | -48.19 kJ/kg |
B. | -58.19 kJ/kg |
C. | -68.19 kJ/kg |
D. | -78.19 kJ/kg |
Answer» B. -58.19 kJ/kg | |