MCQOPTIONS
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MCQOPTIONS
This section includes 156 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
In order that a cycle be reversible, following must be satisfied |
| A. | free expansion or friction resisted expansion/compression process should not be encountered |
| B. | when heat is being absorbed, temperature of hot source and working substance should be same |
| C. | when heat is being rejected, temperature of cold source and working substance should be same |
| D. | All options are correct |
| Answer» E. | |
| 152. |
In which of the following situations, the entropy change is negative? |
| A. | Air expands isothermally from 6 bar to 3 bar |
| B. | Air is compressed to half of it volume at constant pressure |
| C. | Air is supplied with heat at constant volume till its pressure is doubled |
| D. | Air expands adiabatically from 6 bar to 3 bar |
| Answer» C. Air is supplied with heat at constant volume till its pressure is doubled | |
| 153. |
A_CYCLIC_MACHINE,_AS_SHOWN_BELOW,_RECEIVES_325_KJ_FROM_A_1000_K_ENERGY_RESERVOIR._IT_REJECTS_125_KJ_TO_A_400_K_ENERGY_RESERVOIR_AND_THE_CYCLE_PRODUCES_200KJ_OF_WORK_AS_OUTPUT._IS_THIS_CYCLE_REVERSIBLE,_IRREVERSIBLE,_OR_IMPOSSIBLE??$ |
| A. | reversible |
| B. | irreversible |
| C. | impossible |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 154. |
A car engine operates with a thermal efficiency of 35%. Assume the air-conditioner has a coefficient of performance of 3 working as a refrigerator cooling the inside using engine shaft work to drive it. How much fuel energy should be spend extra to remove 1 kJ from the inside?$ |
| A. | 0.752 kJ |
| B. | 0.952 kJ |
| C. | 0.852 kJ |
| D. | none of the mentioned |
| Answer» C. 0.852 kJ | |
| 155. |
In a cryogenic experiment you need to keep a container at -125°C although it gains 100 W due to heat transfer. What is the smallest motor you would need for a heat pump absorbing heat from the container and rejecting heat to the room at 20°C?$# |
| A. | 97.84 kW |
| B. | 98.84 kW |
| C. | 99.84 kW |
| D. | 95.84 kW |
| Answer» B. 98.84 kW | |
| 156. |
An air-conditioner provides 1 kg/s of air at 15°C cooled from outside atmospheric air at 35°C. Estimate the amount of power needed to operate the air-conditioner?# |
| A. | 1.09 kW |
| B. | 1.19 kW |
| C. | 1.29 kW |
| D. | 1.39 kW |
| Answer» E. | |