MCQOPTIONS
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MCQOPTIONS
This section includes 368 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
In a domestic refrigerator, a capillary tube controls the flow of refrigerant from the |
| A. | Expansion valve to the evaporator |
| B. | Evaporator to the thermostat |
| C. | Condenser to the expansion valve |
| D. | Condenser to the evaporator |
| Answer» B. Evaporator to the thermostat | |
| 352. |
Nusselt number (NN) is given by |
| A. | NN = hl/k |
| B. | NN = μ cp/k |
| C. | NN = ρ V l /μ |
| D. | NN = V²/t.cp |
| Answer» B. NN = ≈í¬∫ cp/k | |
| 353. |
In vapour compression refrigeration system, refrigerant occurs as liquid between |
| A. | Condenser and expansion valve |
| B. | Compressor and evaporator |
| C. | Expansion valve and evaporator |
| D. | Compressor and condenser |
| Answer» D. Compressor and condenser | |
| 354. |
Superheating in a refrigeration cycle |
| A. | Increases C.O.P |
| B. | Decreases C.O.P |
| C. | C.O.P remains unaltered |
| D. | Other factors decide C.O.P |
| Answer» C. C.O.P remains unaltered | |
| 355. |
The conditioned air supplied to the room must have the capacity to take up |
| A. | Room sensible heat load only |
| B. | Room latent heat load only |
| C. | Both room sensible heat and latent heat loads |
| D. | None of the above |
| Answer» D. None of the above | |
| 356. |
In mechanical refrigeration system, the refrigerant has the maximum temperature |
| A. | In evaporator |
| B. | Before expansion valve |
| C. | Between compressor and condenser |
| D. | Between condenser and evaporator |
| Answer» D. Between condenser and evaporator | |
| 357. |
In vapour compression cycle using NH‚ÇÉ as refrigerant, initial charge is filled at# |
| A. | Suction of compressor |
| B. | Delivery of compressor |
| C. | High pressure side close to receiver |
| D. | Low pressure side near receiver |
| Answer» D. Low pressure side near receiver | |
| 358. |
When the lower temperature of a refrigerating machine is fixed, then the coefficient of performance can be improved by |
| A. | Operating the machine at higher speeds |
| B. | Operating the machine at lower speeds |
| C. | Raising the higher temperature |
| D. | Lowering the higher temperature |
| Answer» E. | |
| 359. |
An infinite parallel planes with emissivities e‚ÇÅ and e‚ÇÇ, the interchange factor for radiation from surface 1 to surface 2 is given by# |
| A. | (e‚ÇÅ + e‚ÇÇ)/ e‚ÇÅ + e‚ÇÇ - e‚ÇÅe‚ÇÇ |
| B. | 1/e‚ÇÅ + 1/e‚ÇÇ |
| C. | e‚ÇÅ + e‚ÇÇ |
| D. | e‚ÇÅe‚ÇÇ |
| Answer» B. 1/e‚Äö√á√Ö + 1/e‚Äö√á√á | |
| 360. |
In a refrigerating machine, heat rejected is _________ heat absorbed. |
| A. | Equal to |
| B. | Less than |
| C. | Greater than |
| D. | None of these |
| Answer» D. None of these | |
| 361. |
Highest pressure encountered in a refrigeration system should be |
| A. | Critical pressure of refrigerant |
| B. | Much below critical pressure |
| C. | Much above critical pressure |
| D. | Near critical pressure |
| Answer» C. Much above critical pressure | |
| 362. |
In vapour compression cycle, the condition of refrigerant is high pressure saturated liquid |
| A. | After passing through the condenser |
| B. | Before passing through the condenser |
| C. | After passing through the expansion or throttle valve |
| D. | Before entering the expansion valve |
| Answer» E. | |
| 363. |
An important characteristic of absorption system of refrigeration is |
| A. | noisy operation |
| B. | quiet operation |
| C. | cooling below 0°C |
| D. | very little power consumption |
| Answer» C. cooling below 0¬¨‚àûC | |
| 364. |
During a refrigeration cycle, heat is rejected by the refrigerant in a |
| A. | Compressor |
| B. | Condenser |
| C. | Evaporator |
| D. | Expansion valve |
| Answer» C. Evaporator | |
| 365. |
A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of -23°C. The Carnot coefficient of performance of cycle will be# |
| A. | 0.2 |
| B. | 1.2 |
| C. | 5 |
| D. | 6 |
| Answer» D. 6 | |
| 366. |
The value of C.O.P in vapour compression cycle is usually |
| A. | Always less than unity |
| B. | Always more than unity |
| C. | Equal to unity |
| D. | Any one of the above |
| Answer» C. Equal to unity | |
| 367. |
During cooling and dehumidification, dry bulb temperature |
| A. | Remains constant |
| B. | Increases |
| C. | Decreases |
| D. | None of these |
| Answer» D. None of these | |
| 368. |
Cooling water is required for following equipment in ammonia absorption plant |
| A. | Condenser |
| B. | Evaporator |
| C. | Absorber |
| D. | Condenser, absorber and separator (rectifier) |
| Answer» E. | |