7 July, 2021 VideRime 3 Comments 1 category 123456789101112131415161718192021222324252627282930313233343536373839404142434445Show paginatorHide paginator 20%Page 1 of 5 Loading...1. The humidification process, on the psychrometric chart is shown byInclined lineHorizontal lineVertical lineCurved line Loading...2. The evaporator used in household refrigerators isDefrosting evaporatorNon-frosting evaporatorNone of theseFrosting evaporator Loading...3. The refrigerant for a refrigerator should haveHigh latent heatHigh total heatHigh sensible heatLow latent heat Loading...4. In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = Bypass factor)1 - B. P.F.B.P.F. - 11 + B.P.F.1/ B.P.F. Loading...5. In larger industrial and commercial reciprocating compression systems, refrigerant widely used isCarbon dioxideR-12Sulphur dioxideAmmonia Loading...6. The sensible heat factor during cooling and dehumidification process is given by (where h₁ = Enthalpy of air entering the cooling coil, h₂ = Enthalpy of air leaving the cooling coil, and hA = Enthalpy of air at the end of dehumidification process)(hA - h1)/ (h2 - h1)(h2 - hA)/ (h1 - h2)(h1 - h2)/ (hA - h2)(hA - h2)/ (h1 - h2) Loading...7. In vapour compression cycle the condition of refrigerant is superheated vapourBefore entering the expansion valveBefore passing through the condenserAfter passing through the condenserAfter passing through the expansion or throttle valve Loading...8. Most of the domestic refrigerators work on the following refrigeration systemCarnot cycleVapour compressionElectrolux refrigeratorVapour absorption Loading...9. The C.O.P. of an absorption type refrigerator is given by (where T₁ = Temperature at which the working substance receives heat, T₂ = Temperature of cooling water, and T₃ = Evaporator temperature)[T₁ (T₂ - T₃)] / [T₃ (T₁ - T₂)][T₁ (T₁ - T₂)] / [T₃ (T₂ - T₃)][T₃ (T₁ - T₂)]/ [T₁ (T₂ - T₃)][T₃ (T₂ - T₃)] / [T₁ (T₁ - T₂)] Loading...10. Short horizontal lines on pressure-enthalpy chart showConstant pressure linesConstant entropy linesConstant temperature linesConstant total heat linesPage 2 of 5 Loading...11. The dry bulb temperature lines, on the psychrometric chart areHorizontal and uniformly spacedCurved linesHorizontal and non-uniformly spacedVertical and uniformly spaced Loading...12. While designing the refrigeration system of an aircraft, the prime consideration is that theSystem has high C.O.P.Mass of the refrigeration equipment is lowPower per TR is lowMass of refrigerant circulated in the system is low Loading...13. Accumulators should have adequate volume to store refrigerant charge at least10%75%25%50% Loading...14. The mass of water vapour present in __________ is called absolute humidity.1 kg of dry air1 kg of wet air1 m3 of dry air1 m3 of water Loading...15. Chaperon equation is applicable for registration atSaturation point of vapourTriple pointSaturation point of liquidSublimation temperature Loading...16. During adiabatic saturation process on unsaturated air __________ remains constant.Dry bulb temperatureWet bulb temperatureDew point temperatureRelative humidity Loading...17. The refrigerant supplied to a compressor must beDry saturated liquid refrigerantNone of theseA mixture of liquid and vapour refrigerantSuperheated vapour refrigerant Loading...18. In S.J. unit, one ton of refrigeration is equal to420 kJ/ min210 kJ/ min840 kJ/ min21 kJ/ min Loading...19. The temperature of air recorded by a thermometer, when its bulb is surrounded by a wet cloth exposed to the air, is calledDew point temperatureWet bulb temperatureDry bulb temperatureNone of these Loading...20. The ratio of heat extracted in the refrigerator to the work-done on the refrigerant is calledRefrigerating efficiencyRelative coefficient of performanceCoefficient of performance of heat pumpCoefficient of performance of refrigerationPage 3 of 5 Loading...21. In vapour compression cycle the condition off refrigerant is dry saturated vapourBefore passing through the condenserBefore entering the compressorAfter passing through the expansion or throttle valveAfter passing through the condenser Loading...22. The power per tonne of refrigeration isC.O.P/3.53.5/C.O.P.3.5 × C.O.P.None of these Loading...23. The cooling system used for supersonic aircrafts and rockets isSimple air cooling systemBootstrap air cooling systemRegenerative air cooling systemReduced ambient air cooling system Loading...24. The material of pipe lines for a system using Freon as a refrigerant should beBrassCopperAluminiumSteel Loading...25. Ammonia isHighly toxic and inflammableNon-toxicNon-inflammableToxic and non-inflammable Loading...26. In a refrigerating machine, heat rejected is _________ heat absorbed.Greater thanNone of theseLess thanEqual to Loading...27. For ammonia refrigerating systems, the tubes of a shell and tube condenser are made ofCopperBrassSteelAluminium Loading...28. Degree of saturation or percentage humidity isThe ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressureThe mass of water vapour present in 1 kg of dry airThe ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressureThe mass of water vapour present in 1 m³ of dry air Loading...29. In which of the following refrigeration system, waste heat can be effectively used?None of theseAir refrigeration cycleVapour compression cycleVapour absorption cycle Loading...30. For unsaturated air, the dew point temperature is __________ wet bulb temperature.Equal toMore thanNone of theseLess thanPage 4 of 5 Loading...31. Air refrigeration cycle is used inGas liquefactionDomestic refrigeratorsAir conditioningCommercial refrigerators Loading...32. One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of iceIn 1 hourIn 1 minuteIn 12 hoursIn 24 hours Loading...33. Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption systemWeak solution to strong solutionStrong solution to weak solutionAmmonia vapours to weak solutionStrong solution to ammonia vapour Loading...34. The bypass factor for a cooling coilDecreases with increase in velocity of air passing through itIncreases with increase in velocity of air passing through itRemains unchanged with increase in velocity of air passing through itMay increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering Loading...35. The specific humidity during cooling and dehumidificationIncreasesDecreasesRemains constantNone of these Loading...36. Efficiency of a Carnot engine is given as 80%. If the cycle direction be reversed, what will be the value of C.O.P. of reversed Carnot Cycle?1.250.250.80.5 Loading...37. In aqua ammonia and Lithium bromide water absorption refrigeration systems, the refrigerants are respectivelyAmmonia and lithium bromideWater and waterAmmonia and waterWater and lithium bromide Loading...38. In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced byAbsorber, generator and liquid pumpLiquid pumpAbsorber and generatorGenerator Loading...39. The humidity ratio or specific humidity is the mass of water vapour present in1 m3 of wet air1 kg of dry air1 m3 of dry air1 kg of wet air Loading...40. The mass of water vapour present in __________ is called absolute humidity.1 m3 of dry air1 kg of dry air1 m3 of water1 kg of wet airPage 5 of 5 Loading...41. The formation of frost on cooling coils in a refrigeratorIncreases heat transferImproves C.O.P. of the systemReduces power consumptionIncreases power consumption Loading...42. In air-conditioning of aeroplanes, using air as a refrigerant, the cycle used isReversed Otto cycleReversed Carnot cycleReversed Joule cycleReversed Brayton cycle Loading...43. One of the purposes of sub cooling the liquid refrigerant is toEnsure that only liquid and not the vapour enters the expansion (throttling) valveReduce compressor discharge temperatureIncrease cooling effectReduce compressor overheating Loading...44. The reciprocating refrigerant compressors are very suitable forSmall displacements and low condensing pressuresSmall displacements and high condensing pressuresLarge displacements and low condensing pressuresLarge displacements and high condensing pressures Loading...45. The desirable property of a refrigerant isHigh critical temperatureAll of theseHigh latent heat of vaporisationLow boiling point Loading... Share this Now with Friends: Share on WhatsApp (Opens in new window) WhatsApp Share on Telegram (Opens in new window) Telegram MoreRelated Category: Refrigeration & Air-Conditioning 3 Replies to “Refrigeration & Air-Conditioning Practice Set-5”Your point of view caught my eye and was very interesting. Thanks. I have a question for you.ReplyYour article helped me a lot, is there any more related content? Thanks!ReplyCan you be more specific about the content of your article? After reading it, I still have some doubts. Hope you can help me.ReplyLeave a ReplyCancel reply Post navigationPrevious: Difference between Carbon Steel and Stainless steel and their DefinitionsNext: Refrigeration & Air-Conditioning Practice Set-6Related Posts Refrigeration & Air-Conditioning Practice Set-3[watupro 114] Read More Refrigeration & Air-Conditioning Practice Set-6[watupro 136] Read More Refrigeration & Air-Conditioning Practice Set-7[watupro 137] Read More
Can you be more specific about the content of your article? After reading it, I still have some doubts. Hope you can help me.Reply
Your point of view caught my eye and was very interesting. Thanks. I have a question for you.
Your article helped me a lot, is there any more related content? Thanks!
Can you be more specific about the content of your article? After reading it, I still have some doubts. Hope you can help me.