7 June, 2021 VideRime 2 Comments 1 category 123456789101112131415161718192021222324252627282930313233343536373839404142434445Show paginatorHide paginator 20%Page 1 of 5 Loading...1. The condition of refrigerant as it leaves the compressor in a vapour compression system isSuperheated vapourSaturated liquidWet vapourDry saturated vapour Loading...2. The advantage of dry compression is thatIt permits higher speeds to be usedIt permits complete evaporation in the evaporatorIt results in high volumetric and mechanical efficiencyAll of the above Loading...3. The wet bulb temperature at 100% relative humidity is ________ dew point temperature.Lower thanNone of theseHigher thanSame as Loading...4. The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy diagram representsCondensation of the refrigerant vapourMetering of the refrigerant liquidCompression of the refrigerant vapourEvaporation of the refrigerant liquid Loading...5. Which of the following refrigerant has the highest freezing point.R-12AmmoniaCarbon dioxideSulphur dioxide Loading...6. Refrigeration in aeroplanes usually employs the following refrigerantFreon-22Freon-11CO2Air Loading...7. For better C.O.P of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must beSmallEqualHighAnything Loading...8. The thermostatic expansion valve is used in ________ type of evaporators.None of theseDX coilDryFlooded Loading...9. The superheating in a refrigeration cycleDoes not alter C.O.P.Decreases C.O.P.None of theseIncreases C.O.P. Loading...10. A standard ice point temperature corresponds to the temperature ofMixture of ice and water under equilibrium conditionsSolid and dry iceWater at 0°CIce at 4°CPage 2 of 5 Loading...11. Moisture in Freon refrigeration system causesCorrosion of whole systemIneffective refrigerationHigh power consumptionFreezing automatic regulating valve Loading...12. Which of the following statement is correct?The wet bulb temperature is a measure of enthalpy of moist airThe wet bulb and dry bulb temperature are equal at saturation conditionAll of theseThe constant enthalpy lines are also constant wet bulb temperature lines Loading...13. The alignment circle is marked on the psychrometric chart at26°C DBT and 60% RH26°C DBT and 50% RH20°C DBT and 50% RH20°C DBT and 60% RH Loading...14. During sensible cooling,Relative humidity remains constantSpecific humidity increasesWet bulb temperature increasesPartial pressure of vapour remains constant Loading...15. The boiling point of ________ is 10.5°C.R-12Sulphur dioxideCarbon dioxideAmmonia Loading...16. The specific humidity during dehumidification processDecreasesIncreasesNone of theseRemains constant Loading...17. The Freon group of refrigerants areHalocarbon refrigerantsInorganic refrigerantsZoetrope refrigerantsHydrocarbon refrigerants Loading...18. The bypass factor (B. P. F.) in case of sensible heating of air is (Where td₁ = Dry bulb temperature of air entering the heating coil, td₂ = Dry bulb temperature of air leaving the heating coil, and td₃ = Dry bulb temperature of heating coil)(td₃ - td₁)/(td₂ - td₃)(td₂ - td₃)/(td₃ - td₁)(td₃ - td₂)/(td₃ - td₁)(td₃ - td₁)/(td₃ - td₂) Loading...19. The relative coefficient of performance isActual COP × theoretical COPActual COP/theoretical COPTheoretical COP/actual COPNone of these Loading...20. The wet bulb depression indicates _________ humidity of the air.RelativeNone of theseAbsoluteSpecificPage 3 of 5 Loading...21. In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperatureWhich is lower than the dew point temperature of the incoming streamWhich lies between the dry bulb and wet bulb temperatures of the incoming streamOf adiabatic saturation of incoming streamWhich lies between the wet bulb and dew point temperatures of the incoming stream Loading...22. The sensible heat factor during the heating and humidification process is given by (where h₁ = Enthalpy of air entering the heating coil, h₂ = Enthalpy of air leaving the heating coil, and hA = Enthalpy of air at the end of humidification process)(h2 - hA)/ (h1 - h2)(hA - h1)/ (h2 - h1)(hA - h2)/ (h1 - h2)(h1 - h2)/ (hA - h2) Loading...23. Superheating in a refrigeration cycleDecreases C.O.PC.O.P remains unalteredOther factors decide C.O.PIncreases C.O.P Loading...24. During cooling and dehumidification, dry bulb temperatureIncreasesRemains constantNone of theseDecreases Loading...25. A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of -23°C. The Carnot coefficient of performance of cycle will be0.2651.2 Loading...26. In vapour compression refrigeration system, refrigerant occurs as liquid betweenCompressor and condenserExpansion valve and evaporatorCondenser and expansion valveCompressor and evaporator Loading...27. The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases,Will be higherMay be higher or lower depending upon the nature of non-condensable gasesWill remain unaffectedWill be lower Loading...28. Air conditioning meansHeatingDehumidifyingAll of theseCooling Loading...29. The conditioned air supplied to the room must have the capacity to take upNone of the aboveBoth room sensible heat and latent heat loadsRoom latent heat load onlyRoom sensible heat load only Loading...30. Which of the following refrigerants has lowest freezing point?Freon-12CO2NH3Freon-22Page 4 of 5 Loading...31. The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, willIncreaseDecreaseRemain unaffectedMay increase or decrease depending on the type of refrigerant used Loading...32. The coefficient of performance is the ratio of the refrigerant effect to theAll of the aboveEnthalpy increase in compressorHeat of compressionWork done by compressor Loading...33. The index which correlates the combined effects of air temperature, relative humidity and air velocity on the human body, is known asEffective temperatureMean radiant temperatureNone of theseDew point temperature Loading...34. In vapour compression cycle, the condition of refrigerant is very wet vapourBefore passing through the condenserAfter passing through the expansion or throttle valveBefore entering the compressorAfter passing through the condenser Loading...35. Ammonia absorption refrigeration cycle requiresNearly same work input as for vapour compression cycleVery little work inputMaximum work inputZero work input Loading...36. A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be1 kW2 kW4 kW3 kW Loading...37. In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system isThere is no such considerationLess than 2 kgMore than or equal to 3.65 kgMore than 10 kg Loading...38. The sub-cooling in a refrigeration cycleIncreases C.O.P.Decreases C.O.P.Does not alter C.O.P.None of these Loading...39. Relative humidity is given by (where pv = Partial pressure of water vapour, pb = Barometric pressure, ps = Pressure of saturated air, pd = Pressure at dry bulb temperature, pw = Saturation pressure corresponding to wet bulb temperature, and μ = Degree of saturation)μ/[1 - (1 - μ) (Ps/Pb)] [Pv (Pb - Pd)]/ [Pd (Pb - Pv)]None of these0.622 Pv / (Pb - Pv) Loading...40. Air refrigeration operates onCarnot cycleReversed Carnot cycleRankine’s cycleBrayton cyclePage 5 of 5 Loading...41. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant isMore or less depending on ambient conditionsMoreSameLess Loading...42. The leakage in a refrigeration system using Freon is detected bySoap and waterSulphur sticksAll of theseHalide torch Loading...43. Vapour compression refrigeration is somewhat likeReversed Carnot cycleCarnot cycleRankine’s cycleNone of the above Loading...44. Aqua ammonia is used as refrigerant in the following type of refrigeration systemIndirectCompressionDirectAbsorption Loading...45. The specific humidity during heating and humidification process.DecreasesRemains constantIncreasesNone of these Loading... Share this Now with Friends: Share on WhatsApp (Opens in new window) WhatsApp Share on Telegram (Opens in new window) Telegram MoreRelatedTags: Mechanical EngineeringRefrigeration & Air-Conditioning Category: Refrigeration & Air-Conditioning 2 Replies to “Refrigeration & Air-Conditioning Practice Set-4”Your point of view caught my eye and was very interesting. Thanks. I have a question for you. https://www.binance.info/register?ref=IXBIAFVYReplyYour point of view caught my eye and was very interesting. Thanks. I have a question for you.ReplyLeave a ReplyCancel reply Post navigationPrevious: Engineering Drawing MCQs Practice Set-6Next: Building Material MCQs Set-6Related Posts Refrigeration & Air-Conditioning Practice Set-2[watupro 113] Read More Refrigeration & Air-Conditioning Practice Set-7[watupro 137] Read More Refrigeration & Air-Conditioning Practice Set-5[watupro 135] Read More
Your point of view caught my eye and was very interesting. Thanks. I have a question for you. https://www.binance.info/register?ref=IXBIAFVYReply
Your point of view caught my eye and was very interesting. Thanks. I have a question for you. https://www.binance.info/register?ref=IXBIAFVY
Your point of view caught my eye and was very interesting. Thanks. I have a question for you.