7 June, 2021 VideRime 2 Comments 1 category 123456789101112131415161718192021222324252627282930313233343536373839404142434445Show paginatorHide paginator 20%Page 1 of 5 Loading...1. The leakage in a refrigeration system using Freon is detected bySoap and waterAll of theseSulphur sticksHalide torch Loading...2. Aqua ammonia is used as refrigerant in the following type of refrigeration systemDirectAbsorptionCompressionIndirect Loading...3. The specific humidity during dehumidification processNone of theseIncreasesRemains constantDecreases Loading...4. 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)(td₂ - td₃)/(td₃ - td₁)(td₃ - td₁)/(td₃ - td₂)(td₃ - td₂)/(td₃ - td₁)(td₃ - td₁)/(td₂ - td₃) Loading...5. The wet bulb temperature at 100% relative humidity is ________ dew point temperature.Lower thanNone of theseHigher thanSame as Loading...6. Air refrigeration operates onCarnot cycleRankine’s cycleReversed Carnot cycleBrayton cycle Loading...7. 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 kW4 kW3 kW2 kW Loading...8. Refrigeration in aeroplanes usually employs the following refrigerantCO2Freon-22AirFreon-11 Loading...9. The superheating in a refrigeration cycleNone of theseDecreases C.O.P.Does not alter C.O.P.Increases C.O.P. Loading...10. During sensible cooling,Wet bulb temperature increasesRelative humidity remains constantSpecific humidity increasesPartial pressure of vapour remains constantPage 2 of 5 Loading...11. 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)]None of these [Pv (Pb - Pd)]/ [Pd (Pb - Pv)]0.622 Pv / (Pb - Pv) Loading...12. The condition of refrigerant as it leaves the compressor in a vapour compression system isWet vapourSaturated liquidDry saturated vapourSuperheated vapour Loading...13. The alignment circle is marked on the psychrometric chart at26°C DBT and 50% RH20°C DBT and 50% RH20°C DBT and 60% RH26°C DBT and 60% RH Loading...14. The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy diagram representsMetering of the refrigerant liquidEvaporation of the refrigerant liquidCompression of the refrigerant vapourCondensation of the refrigerant vapour Loading...15. The wet bulb depression indicates _________ humidity of the air.RelativeSpecificAbsoluteNone of these Loading...16. The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, willRemain unaffectedDecreaseIncreaseMay increase or decrease depending on the type of refrigerant used Loading...17. In vapour compression refrigeration system, refrigerant occurs as liquid betweenCompressor and evaporatorCondenser and expansion valveCompressor and condenserExpansion valve and evaporator Loading...18. A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of -23°C. The Carnot coefficient of performance of cycle will be60.251.2 Loading...19. The conditioned air supplied to the room must have the capacity to take upRoom latent heat load onlyBoth room sensible heat and latent heat loadsRoom sensible heat load onlyNone of the above Loading...20. 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)(hA - h1)/ (h2 - h1)(h2 - hA)/ (h1 - h2)(hA - h2)/ (h1 - h2)(h1 - h2)/ (hA - h2)Page 3 of 5 Loading...21. The thermostatic expansion valve is used in ________ type of evaporators.DX coilFloodedDryNone of these Loading...22. The specific humidity during heating and humidification process.Remains constantDecreasesIncreasesNone of these Loading...23. 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 wet bulb and dew point temperatures of the incoming streamOf adiabatic saturation of incoming streamWhich lies between the dry bulb and wet bulb temperatures of the incoming stream Loading...24. The Freon group of refrigerants areHalocarbon refrigerantsInorganic refrigerantsZoetrope refrigerantsHydrocarbon refrigerants Loading...25. A standard ice point temperature corresponds to the temperature ofMixture of ice and water under equilibrium conditionsSolid and dry iceIce at 4°CWater at 0°C Loading...26. The boiling point of ________ is 10.5°C.AmmoniaR-12Carbon dioxideSulphur dioxide Loading...27. During cooling and dehumidification, dry bulb temperatureNone of theseIncreasesRemains constantDecreases Loading...28. Which of the following refrigerant has the highest freezing point.Carbon dioxideAmmoniaSulphur dioxideR-12 Loading...29. The advantage of dry compression is thatIt results in high volumetric and mechanical efficiencyIt permits complete evaporation in the evaporatorAll of the aboveIt permits higher speeds to be used Loading...30. 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 conditionThe constant enthalpy lines are also constant wet bulb temperature linesAll of thesePage 4 of 5 Loading...31. The sub-cooling in a refrigeration cycleDoes not alter C.O.P.None of theseDecreases C.O.P.Increases C.O.P. Loading...32. The index which correlates the combined effects of air temperature, relative humidity and air velocity on the human body, is known asNone of theseEffective temperatureDew point temperatureMean radiant temperature Loading...33. In vapour compression cycle, the condition of refrigerant is very wet vapourAfter passing through the expansion or throttle valveBefore passing through the condenserAfter passing through the condenserBefore entering the compressor Loading...34. Air conditioning meansAll of theseCoolingHeatingDehumidifying Loading...35. The coefficient of performance is the ratio of the refrigerant effect to theAll of the aboveWork done by compressorEnthalpy increase in compressorHeat of compression Loading...36. For better C.O.P of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must beAnythingHighSmallEqual Loading...37. Superheating in a refrigeration cycleIncreases C.O.POther factors decide C.O.PC.O.P remains unalteredDecreases C.O.P Loading...38. The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant isMore or less depending on ambient conditionsMoreLessSame Loading...39. The relative coefficient of performance isTheoretical COP/actual COPActual COP × theoretical COPActual COP/theoretical COPNone of these Loading...40. Vapour compression refrigeration is somewhat likeReversed Carnot cycleNone of the aboveRankine’s cycleCarnot cyclePage 5 of 5 Loading...41. Ammonia absorption refrigeration cycle requiresMaximum work inputZero work inputNearly same work input as for vapour compression cycleVery little work input Loading...42. Which of the following refrigerants has lowest freezing point?NH3Freon-22CO2Freon-12 Loading...43. The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases,May be higher or lower depending upon the nature of non-condensable gasesWill be lowerWill be higherWill remain unaffected Loading...44. Moisture in Freon refrigeration system causesCorrosion of whole systemHigh power consumptionFreezing automatic regulating valveIneffective refrigeration Loading...45. In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system isMore than 10 kgLess than 2 kgThere is no such considerationMore than or equal to 3.65 kg 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-7[watupro 137] Read More Refrigeration & Air-Conditioning Practice Set-1[watupro 112] 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.