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This set of Thermal Engineering 2 Multiple Choice Questions & Answers (MCQs) focuses on Thermal Engineering II Set 20
Q1 | Compression can be
- dry compression
- wet compression
- both of the mentioned
- none of the mentioned
Q2 | Wet compression is preferred over dry compression.
- true
- false
- topic 5.1 vapour compression refrigeration cycle, effect of superheat and sub-cooling, performance calculations
Q3 | Why is wet compression not preferred?
- the liquid refrigerant can be trapped in the head of cylinder
- this may damage the valves or cylinder head
- liquid refrigerant can wash away the lubricating oil thus accelerating wear
- all of the mentioned
Q4 | The expansion process is
- isentropic
- reversible
- adiabatic
- all of the mentioned
Q5 | The evaporation process is a
- constant volume reversible process
- constant pressure reversible process
- adiabatic throttling process
- reversible adiabatic process
Q6 | The evaporator produces the cooling or refrigerating effect.
- true
- false
Q7 | In the expansion process, which of the following remains constant?
- work done
- heat supplied
- internal energy
- enthalpy
Q8 | The COP of cycle is given by(Q2=heat absorbed by evaporator and Wc=work done by compressor)
- 1- (q2/wc)
- 1- (wc/q2)
- q2/wc
- wc/q2
Q9 | One tonne of refrigeration is given as the rate of heat removal from surroundings equivalent to heat required for melting one tonne of ice in a day.
- true
- false
Q10 | Which of the following is recommended in a refrigeration cycle?
- superheating of vapour
- subcooling of liquid
- both of the mentioned
- none of the mentioned
Q11 | Superheating of vapour and subcooling of liquid the refrigerating effect.
- decreases
- increases
- no change
- none of the mentioned
Q12 | A condenser must and then the compressed refrigerant.
- superheat, evaporate
- desuperheat, evaporate
- superheat, condense
- desuperheat, condense
Q13 | In absorption refrigeration cycle, which of the following is used?
- refrigerant
- absorbent
- both of the mentioned
- none of the mentioned
Q14 | In absorption system, compressor in vapour compression cycle is replaced by absorber- generator assembly.
- true
- false
Q15 | In the aqua-ammonia absorption system,
- water is the refrigerant and ammonia is the absorbent
- ammonia is the refrigerant and water is the absorbent
- both ammonia and water can be used as refrigerant or absorbent
- none of the mentioned
Q16 | Which of the following statement is true?
- ammonia vapour is absorbed in water
- boiling point of ammonia is more than that of water
- both of the mentioned
- none of the mentioned
Q17 | Which of the following condenses first?
- ammonia vapour
- water vapour
- both condense at same temperature
- none of the mentioned
Q18 | The vapour going to condenser is in temperature and in ammonia.
- higher, less
- higher, richer
- lower, less
- lower, richer
Q19 | Lithium bromide-water vapour is another absorption refrigeration system.
- true
- false
Q20 | Water is used as a in air conditioning units.
- absorbent
- refrigerant
- absorbent and refrigerant
- none of the mentioned
Q21 | Room air conditioners and packaged units are examples of
- direct expansion systems
- indirect expansion systems
- chilled water systems
- indirect contraction systems
Q22 | Which of the following is not a component of packaged air conditioners?
- compressor
- condenser
- chiller
- evaporator
Q23 | In a chilled water system, the refrigerant is used to cool the air directly while in the direct expansion system, a secondary medium like water is used to cool the air.
- true
- false
Q24 | In which component of the chilled water system, the return air and the fresh air mixture is filtered?
- fan coil unit
- ducting grill
- compressor
- evaporator
Q25 | Which of the following qualities is not possessed by the filters in the air conditioning system?
- they should be capable of removing dust particles from the incoming air
- they should afford easy cleaning
- they should offer low frictional resistance to the airflow
- they should offer high frictional resistance to the airflow