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**171. For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be:**
– **A. small**
– B. high
– C. equal
– D. anything
– E. under some conditions small and under some conditions high

**172. Air refrigeration cycle is used in:**
– A. domestic refrigerators
– B. commercial refrigerators
– C. air conditioning
– **D. gas liquefaction**
– E. such a cycle does not exist

**173. The bank of tubes at the back of domestic refrigerator are:**
– **A. condenser tubes**
– B. evaporator tubes
– C. refrigerant cooling tubes
– D. capillary tubes
– E. throttling device

**174. The higher temperature in vapour compression cycle occurs at:**
– A. receiver
– B. expansion valve
– C. evaporator
– D. condenser discharge
– **E. compressor discharge**

**175. The vapor pressure of refrigerant should be:**
– A. lower than atmospheric pressure
– **B. higher than atmospheric pressure**
– C. equal to atmospheric pressure
– D. could be anything
– E. none of the above

**176. Critical pressure of a liquid is the pressure:**
– A. above which liquid will remain liquid
– **B. above which liquid becomes gas**
– C. above which liquid becomes vapour
– D. above which liquid becomes solid
– E. at which all the three phases exist together

**177. In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is:**
– A. less than 2 kg
– **B. more than or equal to 3.65 kg**
– C. more than 10 kg
– D. there is no such consideration
– E. none of the above

**178. The value of COP 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
– E. none of the above

**179. Condensing temperature in a refrigerator is the temperature:**
– A. of cooling medium
– B. of freezing zone
– C. of evaporator
– **D. at which refrigerant gas becomes liquid**
– E. condensing temperature of ice

**180. In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be:**
– A. high, of the order of 25°
– **B. as low as possible (3 to 11°C)**
– C. zero
– D. any value
– E. none of the above