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.
| 101. |
*/*_The capillary tube is not used in large capacity refrigeration systems because? |
| A. | Cost is too high |
| B. | Capacity control is not possible |
| C. | It is made of copper |
| D. | Required pressure drop cannot be achieved |
| Answer» C. It is made of copper | |
| 102. |
*/*_Under cooling 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» B. Decreases C.O.P | |
| 103. |
*/*_The capillary tube, as an expansion device, is used in? |
| A. | Domestic refrigerators |
| B. | Water coolers |
| C. | Room air conditioners |
| D. | All of these |
| Answer» E. | |
| 104. |
*/*_For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is ________ that for counter flow.? |
| A. | Equal to |
| B. | Less than |
| C. | Greater than |
| D. | None of these |
| Answer» B. Less than | |
| 105. |
*/*_A good refrigerant should have? |
| A. | High latent heat of vaporisation and low freezing point |
| B. | High operating pressures and low freezing point |
| C. | High specific volume and high latent heat of vaporisation |
| D. | Low C.O.P. and low freezing point |
| Answer» B. High operating pressures and low freezing point | |
| 106. |
*/*_A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be? |
| A. | 1.33 |
| B. | 2.33 |
| C. | 3.33 |
| D. | 4.33 |
| Answer» C. 3.33 | |
| 107. |
*/*_The condition of refrigerant after passing through the condenser in a vapour compression system is? |
| A. | Saturated liquid |
| B. | Wet vapour |
| C. | Dry saturated vapour |
| D. | Superheated vapour |
| Answer» B. Wet vapour | |
| 108. |
*/*_The difference between dry bulb temperature and dew point temperature, is called? |
| A. | Dry bulb depression |
| B. | Wet bulb depression |
| C. | Dew point depression |
| D. | Degree of saturation |
| Answer» D. Degree of saturation | |
| 109. |
*/*_Chaperon equation is applicable for registration at? |
| A. | Saturation point of vapour |
| B. | Saturation point of liquid |
| C. | Sublimation temperature |
| D. | Triple point |
| Answer» B. Saturation point of liquid | |
| 110. |
*/*_During sensible cooling,? |
| A. | Relative humidity remains constant |
| B. | Wet bulb temperature increases |
| C. | Specific humidity increases |
| D. | Partial pressure of vapour remains constant |
| Answer» E. | |
| 111. |
*/*_Rating of a domestic refrigerator is of the order of? |
| A. | 0.1 ton |
| B. | 5 tons |
| C. | 10 tons |
| D. | 40 tons |
| Answer» B. 5 tons | |
| 112. |
*/*_The evolution of heat of solution takes place in ammonia absorption plant when? |
| A. | Ammonia vapour goes into solution |
| B. | Ammonia vapour is driven out of solution |
| C. | Lithium bromide mixes with ammonia |
| D. | Weak solution mixes with strong solution |
| Answer» B. Ammonia vapour is driven out of solution | |
| 113. |
*/*_Aqua ammonia is used as refrigerant in the following type of refrigeration system? |
| A. | Compression |
| B. | Direct |
| C. | Indirect |
| D. | Absorption |
| Answer» E. | |
| 114. |
*/*_The operating pressure for refrigerating units using R-12 as a refrigerant is? |
| A. | 2 bar |
| B. | 8 bar |
| C. | 15 bar |
| D. | 30 bar |
| Answer» C. 15 bar | |
| 115. |
*/*_In S.J. unit, one ton of refrigeration is equal to? |
| A. | 210 kJ/ min |
| B. | 21 kJ/ min |
| C. | 420 kJ/ min |
| D. | 840 kJ/ min |
| Answer» B. 21 kJ/ min | |
| 116. |
*/*_The process, generally used in summer air conditioning to cool and dehumidify the air, is called? |
| A. | Humidification |
| B. | Dehumidification |
| C. | Heating and humidification |
| D. | Cooling and dehumidification |
| Answer» E. | |
| 117. |
*/*_For obtaining high COP, the pressure range of compressor should be? |
| A. | High |
| B. | Low |
| C. | Optimum |
| D. | Any value |
| Answer» C. Optimum | |
| 118. |
*/*_The coefficient of performance of Heat Pump is always _________ one.? |
| A. | Equal to |
| B. | Less than |
| C. | Greater than |
| D. | None of these |
| Answer» D. None of these | |
| 119. |
*/*_Which of the following statement is correct for ammonia as a refrigerant?? |
| A. | It is toxic to mucous membranes. |
| B. | It requires large displacement per TR compared to fluoro carbons. |
| C. | It reacts with copper and its alloys. |
| D. | All of these |
| Answer» E. | |
| 120. |
*/*_Pressure of water vapour is given by? |
| A. | 0.622 Pv/ (Pb - Pv) |
| B. | μ/[1 - (1 - μ) (Ps/Pb)] |
| C. | [Pv (Pb - Pd)]/ [Pd (Pb - Pv)] |
| D. | None of these |
| Answer» E. | |
| 121. |
*/*_Ammonia is? |
| A. | Non-toxic |
| B. | Non-inflammable |
| C. | Toxic and non-inflammable |
| D. | Highly toxic and inflammable |
| Answer» E. | |
| 122. |
*/*_Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system? |
| A. | Strong solution to weak solution |
| B. | Weak solution to strong solution |
| C. | Strong solution to ammonia vapour |
| D. | Ammonia vapours to weak solution |
| Answer» C. Strong solution to ammonia vapour | |
| 123. |
*/*_In a spray washing system, if the temperature of water is higher than the dry bulb temperature of entering air, then the air is? |
| A. | Heated and dehumidified |
| B. | Heated and humidified |
| C. | Cooled and humidified |
| D. | Cooled and dehumidified |
| Answer» C. Cooled and humidified | |
| 124. |
*/*_The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is? |
| A. | Same |
| B. | More |
| C. | Less |
| D. | More or less depending on ambient conditions |
| Answer» D. More or less depending on ambient conditions | |
| 125. |
*/*_In vapour compression cycle, the condition of refrigerant is saturated liquid? |
| A. | After passing through the condenser |
| B. | Before passing through the condenser |
| C. | After passing through the expansion throttle valve |
| D. | Before entering the expansion valve |
| Answer» B. Before passing through the condenser | |
| 126. |
*/*_The power per tonne of refrigeration is? |
| A. | 3.5/C.O.P. |
| B. | C.O.P/3.5 |
| C. | 3.5 √ó C.O.P. |
| D. | None of these |
| Answer» B. C.O.P/3.5 | |
| 127. |
*/*_The coefficient of performance (C.O.P.) of a refrigerator working as a heat pump is given by? |
| A. | (C.O.P.)P = (C.O.P.)R + 2 |
| B. | (C.O.P.)P = (C.O.P.)R + 1 |
| C. | (C.O.P)P = (C.O.P)R - 1 |
| D. | (C.O.P)P = (C.O.P)R |
| Answer» C. (C.O.P)P = (C.O.P)R - 1 | |
| 128. |
*/*_In a refrigeration system, heat absorbed in comparison to heat rejected is? |
| A. | More |
| B. | Less |
| C. | Same |
| D. | More for small capacity and less for high capacity |
| Answer» C. Same | |
| 129. |
*/*_Air refrigeration cycle is used in? |
| A. | Domestic refrigerators |
| B. | Commercial refrigerators |
| C. | Air conditioning |
| D. | Gas liquefaction |
| Answer» E. | |
| 130. |
*/*_During heating and dehumidification process, dry bulb temperature? |
| A. | Remains constant |
| B. | Increases |
| C. | Decreases |
| D. | None of these |
| Answer» C. Decreases | |
| 131. |
*/*_Accumulators should have adequate volume to store refrigerant charge at least? |
| A. | 10% |
| B. | 25% |
| C. | 50% |
| D. | 75% |
| Answer» D. 75% | |
| 132. |
*/*_Short horizontal lines on pressure-enthalpy chart show? |
| A. | Constant pressure lines |
| B. | Constant temperature lines |
| C. | Constant total heat lines |
| D. | Constant entropy lines |
| Answer» B. Constant temperature lines | |
| 133. |
*/*_The humidity ratio or specific humidity is the mass of water vapour present in? |
| A. | 1 m3 of wet air |
| B. | 1 m3 of dry air |
| C. | 1 kg of wet air |
| D. | 1 kg of dry air |
| Answer» E. | |
| 134. |
*/*_Wet bulb temperature is the temperature of air recorded by a thermometer, when? |
| A. | It is not affected by the moisture present in the air |
| B. | Its bulb is surrounded by a wet cloth exposed to the air |
| C. | The moisture present in it begins to condense |
| D. | None of the above |
| Answer» C. The moisture present in it begins to condense | |
| 135. |
*/*_The refrigerant used for absorption refrigerators working on heat from solar collectors is a mixture of water and? |
| A. | Carbon dioxide |
| B. | Sulphur dioxide |
| C. | Lithium bromide |
| D. | R-12 |
| Answer» D. R-12 | |
| 136. |
*/*_The superheated vapour region, in a pressure enthalpy chart, is represented by the space? |
| A. | To the left of saturated liquid line |
| B. | To the right of saturated liquid line |
| C. | Between the saturated liquid line and saturated vapour line |
| D. | None of the above |
| Answer» D. None of the above | |
| 137. |
*/*_The formation of frost on cooling coils in a refrigerator? |
| A. | Increases heat transfer |
| B. | Improves C.O.P. of the system |
| C. | Increases power consumption |
| D. | Reduces power consumption |
| Answer» D. Reduces power consumption | |
| 138. |
*/*_If a gas is to be liquefied, its temperature must be? |
| A. | Increased to a value above its critical temperature |
| B. | Reduced to a value below its critical temperature |
| C. | Equal to critical temperature |
| D. | None of the above |
| Answer» D. None of the above | |
| 139. |
*/*_In actual air-conditioning applications for R-12 and R-22, and operating at a condenser temperature of 40° C and an evaporator temperature of 5° C, the heat rejection factor is about? |
| A. | 1 |
| B. | 1.25 |
| C. | 2.15 |
| D. | 5.12 |
| Answer» C. 2.15 | |
| 140. |
*/*_A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be? |
| A. | 1/4 |
| B. | 1/3 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 141. |
*/*_The wet bulb depression indicates _________ humidity of the air.? |
| A. | Absolute |
| B. | Relative |
| C. | Specific |
| D. | None of these |
| Answer» C. Specific | |
| 142. |
*/*_The material of pipe lines for a system using Freon as a refrigerant should be? |
| A. | Brass |
| B. | Copper |
| C. | Steel |
| D. | Aluminium |
| Answer» C. Steel | |
| 143. |
%_The humidity ratio or specific humidity is the mass of water vapour present in_% |
| A. | 1 m3 of wet air |
| B. | 1 m3 of dry air |
| C. | 1 kg of wet air |
| D. | 1 kg of dry air |
| Answer» E. | |
| 144. |
%_The refrigerant used for absorption refrigerators working on heat from solar collectors is a mixture of water and_% |
| A. | Carbon dioxide |
| B. | Sulphur dioxide |
| C. | Lithium bromide |
| D. | R-12 |
| Answer» D. R-12 | |
| 145. |
%_Accumulators should have adequate volume to store refrigerant charge at least_% |
| A. | 10% |
| B. | 25% |
| C. | 50% |
| D. | 75% |
| Answer» D. 75% | |
| 146. |
%_Short horizontal lines on pressure-enthalpy chart show_% |
| A. | Constant pressure lines |
| B. | Constant temperature lines |
| C. | Constant total heat lines |
| D. | Constant entropy lines |
| Answer» B. Constant temperature lines | |
| 147. |
_ The wet bulb depression indicates _________ humidity of the air.$? |
| A. | Absolute |
| B. | Relative |
| C. | Specific |
| D. | None of these |
| Answer» C. Specific | |
| 148. |
_ A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be$? |
| A. | 1/4 |
| B. | 1/3 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 149. |
_ The formation of frost on cooling coils in a refrigerator$? |
| A. | Increases heat transfer |
| B. | Improves C.O.P. of the system |
| C. | Increases power consumption |
| D. | Reduces power consumption |
| Answer» D. Reduces power consumption | |
| 150. |
_ The material of pipe lines for a system using Freon as a refrigerant should be$? |
| A. | Brass |
| B. | Copper |
| C. | Steel |
| D. | Aluminium |
| Answer» C. Steel | |