MCQOPTIONS
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MCQOPTIONS
This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Refrigeration knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Out of the following reasons which one is responsible for Carnot cycle not being used in practice? |
| A. | It gives low COP |
| B. | It gives high refrigeration effect |
| C. | It gives low refrigeration effect |
| D. | It has low theoretical efficiency |
| Answer» D. It has low theoretical efficiency | |
| 2. |
What is the COP of a refrigerator when it’s refrigerating effect R is 6.2755 KW and work consumed is 0.82 KW? |
| A. | 8.8 |
| B. | 6.77 |
| C. | 7.65 |
| D. | 8.56 |
| Answer» D. 8.56 | |
| 3. |
For a refrigerating system that works on Carnot cycle having air or gas as refrigerant s, which one of the following is not a process of the cycle in p-v diagram? |
| A. | Adiabatic compression process |
| B. | Isothermal compression process |
| C. | Adiabatic expansion process |
| D. | Isentropic expansion process |
| Answer» E. | |
| 4. |
Which one is not a limitation of the Carnot cycle with air or gas as refrigerant? |
| A. | It has low efficiency when working between two fixed temperature limits |
| B. | Machine has to run at high and low speeds during adiabatic and isothermal process. Such variation of speed is not possible |
| C. | Extreme pressure and large volume are developed |
| D. | It is not possible to carry out isothermal heat transfer process in practice |
| Answer» B. Machine has to run at high and low speeds during adiabatic and isothermal process. Such variation of speed is not possible | |
| 5. |
The COPr of a Carnot refrigerating machine is 7.89. What will be the COPp of heat pump? |
| A. | 10.3 |
| B. | 7.89 |
| C. | 8.89 |
| D. | 6.89 |
| Answer» D. 6.89 | |
| 6. |
A refrigerating machine working on Carnot cycle operates between 300K and 250K. Determine the COP. |
| A. | 5 |
| B. | 6 |
| C. | 4 |
| D. | 10 |
| Answer» B. 6 | |
| 7. |
What happens to the COP of a Carnot refrigerator in summer and in winter? |
| A. | The COP is more in winter |
| B. | The COP is more in summer |
| C. | The COP remains unaffected |
| D. | The COP fluctuates continuously during winter and summer |
| Answer» B. The COP is more in summer | |
| 8. |
The COP of refrigerator may be improved by _________ |
| A. | decreasing the higher (T2) as well as the lower (T1) temperature |
| B. | decreasing the higher (T2) temperature and increasing the lower (T1) temperature |
| C. | increasing the higher (T2) as well as the lower (T1) temperature |
| D. | keeping the higher (T2) temperature the same while decreasing the lower (T1) temperature |
| Answer» C. increasing the higher (T2) as well as the lower (T1) temperature | |
| 9. |
What is the coefficient of performance of the refrigerant system working on reversed Carnot cycle, having Qa as heat absorbed by the air during isothermal expansion per kg of air and Qr as heat rejected during isothermal compression per kg of air?a) COP=\(\frac{Q_a}{(Q_r – Q_a)}\) b) COP=\(\frac{Q_r}{(Q_r – Q_a)}\) c) COP=\(\frac{Q_a}{(Q_r + Q_ |
| A. | COP=\(\frac{Q_a}{(Q_r – Q_a)}\) |
| B. | COP=\(\frac{Q_r}{(Q_r – Q_a)}\) |
| C. | COP=\(\frac{Q_a}{(Q_r + Q_a)}\) |
| D. | COP=\(\frac{Q_a}{(Q_a – Q_r)}\) |
| Answer» B. COP=\(\frac{Q_r}{(Q_r – Q_a)}\) | |
| 10. |
For a refrigerating system that works on reversed Carnot cycle having vapor as refrigerant, which one of the following is not a process of the cycle in p-v diagram? |
| A. | Isentropic compression process |
| B. | Isothermal compression process |
| C. | Adiabatic expansion process |
| D. | Isothermal expansion process |
| Answer» D. Isothermal expansion process | |