MCQOPTIONS
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MCQOPTIONS
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. |
During the winter season, a room is heated by central heating furnace which delivers the 750 W of heat energy by burning wood pellets. How much power can be saved if heat pump with a COP of 3 is used instead of furnace? |
| A. | 100 W |
| B. | 500 W |
| C. | 1000 W |
| D. | 1500 W |
| Answer» C. 1000 W | |
| 2. |
A Carnot heat engine receives heat at 750 K and rejects the waste heat to the environment at 300 K. The net work output of the heat engine is used to drive a Carnot refrigerator, whose COP is 6.14. If the heat removal rate from the refrigerated space is 6.6 kW, determine the rate of heat supply to the heat engine? |
| A. | 2.79 kW |
| B. | 1.79 kW |
| C. | 4.79 kW |
| D. | 7.79 kW |
| Answer» C. 4.79 kW | |
| 3. |
The refrigerant R-22 is contained in a piston/cylinder where the volume is 11 L when the piston hits the stops. The initial state is 30 C, 150 kPa with a volume of 10 L. This system is brought indoors and warms up to 15 C. Find the work done by the R-22 during this process. |
| A. | -0.15 kJ |
| B. | 0.15 kJ |
| C. | -0.35 kJ |
| D. | 0.35 kJ |
| Answer» C. -0.35 kJ | |
| 4. |
A steam turbine receives steam at 6 MPa, 800 C. It has a heat loss of 49.7 kJ/kg and an isentropic efficiency of 90%. For an exit pressure of 15 kPa and surroundings at 20 C, find the actual work. |
| A. | 2233.79 kJ/kg |
| B. | 2423.95 kJ/kg |
| C. | 2483.95 kJ/kg |
| D. | 1648.79 kJ/kg |
| Answer» E. | |
| 5. |
A steam turbine inlet is at 1200 kPa, 500 C. The actual exit is at 300 kPa, 300 C with an actual work of 407 kJ/kg. What is its reversible work output if ambient temperature is at 25 C? |
| A. | 414.9 kJ/kg |
| B. | 314.9 kJ/kg |
| C. | 214.9 kJ/kg |
| D. | 614.9 kJ/kg |
| Answer» B. 314.9 kJ/kg | |
| 6. |
A piston cylinder contains 3 kg of air at 20 C and 300 kPa. It is now heated up in a constant pressure process to 600 K. Find the heat transfer. |
| A. | 641 kJ |
| B. | 741 kJ |
| C. | 841 kJ |
| D. | 941 kJ |
| Answer» E. | |
| 7. |
A 250 L rigid tank contains methane at 500 K, 1500 kPa. It is now cooled down to 300 K. Find the heat transfer using ideal gas. |
| A. | 402.4 kJ |
| B. | 502.4 kJ |
| C. | 602.4 kJ |
| D. | 702.4 kJ |
| Answer» C. 602.4 kJ | |
| 8. |
Air (an ideal gas) at 227 C and 500 kPa is allowed to expand to a pressure of 100 kPa in an ideal throttling process. What will be the final temperature of the expanded air? |
| A. | 230 C |
| B. | 227 C |
| C. | 300 C |
| D. | 327 C |
| Answer» C. 300 C | |
| 9. |
19 mm thick fibre panels with thermal conductivity of 0.12 W/m.K are used for false ceiling of an AC room. If the floor area of the room is 17.65 m^2 and the temperature difference across the fibre panel is 15 C, calculate the heat transfer rate. |
| A. | 4.672 kW |
| B. | 3.672 kW |
| C. | 2.672 kW |
| D. | 1.672 kW |
| Answer» E. | |
| 10. |
The force needed to compress a non-linear spring is given by F = 200x + 30x^2, where F is force in Newton and x is displacement of the spring in meter. Determine the work needed to compress the spring a distance of 0.6 m. |
| A. | 32.46 J |
| B. | 23.43 J |
| C. | 38.16 J |
| D. | 48.87 J |
| Answer» D. 48.87 J | |