MCQOPTIONS
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MCQOPTIONS
This section includes 7 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A thermal reservoir at 538 C is brought into thermal communication with another thermal reservoir at 260 C, and as a result 1055 kJ of heat is transferred only from the higher to lower temperature reservoir. Determine the change in entropy of the universe due to the exchange of heat between these two thermal reservoirs. |
| A. | 0.378182 kJ/K |
| B. | 0.478182 kJ/K |
| C. | 0.578182 kJ/K |
| D. | 0.678182 kJ/K |
| Answer» E. | |
| 2. |
Two kilograms of water at 120 C with a quality of 25% has its temperature raised by 20 C in a constant volume process. What is the new specific entropy? |
| A. | 3.01517 kJ/kg.K |
| B. | 4.01517 kJ/kg.K |
| C. | 5.01517 kJ/kg.K |
| D. | 7.01517 kJ/kg.K |
| Answer» C. 5.01517 kJ/kg.K | |
| 3. |
Calculate the change in entropy if 1 kg of saturated liquid at 30 C is converted into superheated steam at 1 bar and 200 C . |
| A. | 5.3973 kJ/K |
| B. | 6.3973 kJ/K |
| C. | 7.3973 kJ/K |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 4. |
A foundry form box with 25 kg of 200 C hot sand is dropped into a bucket with 50 L water at 15 C. Assuming there is no heat transfer with the surroundings and no boiling away of water, calculate the net entropy change for the process. |
| A. | 2.37 kJ/K |
| B. | 2.47 kJ/K |
| C. | 2.57 kJ/K |
| D. | 2.67 kJ/K |
| Answer» D. 2.67 kJ/K | |
| 5. |
A slab of concrete, 5 8 0.3 m, is used as a thermal storage mass in a house. The slab cools overnight from 23 C to 18 C in an 18 C house, find the net entropy change associated with this process? |
| A. | 0.4 kJ/K |
| B. | 1.4 kJ/K |
| C. | 2.4 kJ/K |
| D. | 3.4 kJ/K |
| Answer» E. | |
| 6. |
A car uses power of 25 hp for a one hour in a round trip. A thermal efficiency of 35% can be assumed? Find the change in entropy if we assume ambient at 20 C? |
| A. | 554.1 kJ/K |
| B. | 654.1 kJ/K |
| C. | 754.1 kJ/K |
| D. | 854.1 kJ/K |
| Answer» C. 754.1 kJ/K | |
| 7. |
For the flow of electric current through a resistor, |
| A. | at steady state, internal energy of resistor is constant |
| B. | at steady state, temperature of resistor is constant |
| C. | W=Q |
| D. | all of the mentioned |
| Answer» E. | |