Refrigeration and Air-conditioning MCQ with answers

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Refrigeration and Air-conditioning MCQ question and answers (100% free pdf download)

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Q. 1 What is refrigeration?
a) Heat removal
b) heat addition
c) Work absorption
d) work addition

Q2. Refrigerators and heat pumps are
a) Work producers
b) work absorbers
c) heat exchangers
d) expansion devices

Q.3 In Refrigerators heat is absorbed from body to be cooled at temperature
a) Atmospheric
b) less than atmospheric
c) at condenser temperature
d) above atmospheric

Q.4 What is the value of 1 ton of refrigeration
a) 3.5 KW
b) 3KW
c) 4.5KW
d) 4kW

Q.5 What is a heat pump
a) Reversed heat engine
b) pump
c) heat engine
d) compressor

Q.6 In vapour compression system the condensation process is done at
a) constant temperature and pressure
b) constant volume and entropy
c) constant entropy and pressure
d) constant pressure and volume

Q.7 In vapour compression system the heat absorption process is done at
a) constatnt temperature and pressure
b) constant volume and entropy
c) constant entropy and pressure
d) constant pressure and volume

Q.8 Expansion process is ideally a process of
a) Constant enthalpy
b) constant pressure
c) constant temperature
d) constant entropy

Q.9 If the condenser pressure is increased then the COP of the refrigeration system will
a) increase
b) decrease
c) no effect
d) will not work

Q.10 If the evaporator pressure is reduced then the COP will
a) increase
b) decrease
c) no effect
d) will not work

Q.11 The compression process in refrigeration process ic
a) isenthalpic
b) isobaric
c) isochoric
d) isentropic

Q.12 In wet compression the refrigerant is at entry of compression is
a) wet
b) superheated
c) dry saturated
d) no effect

Q.13 In dry compression refrigeration system the refrigerant at entry of compressor is
a) wet
b) superheated
c) dry saturated
d) no effect

Q.14 In wet compression the refrigerant is at exit of compression is
a) wet
b) superheated
c) dry saturated
d) no effect

Q.15 If the liquid refrigerant is sub cooled after condensation then COP will
a) increase
b) decrease
c) no effect
d) will not work

Q.16 The COP in use of flash chamber in refrigerator will
a) increase
b) decrease
c) no effect
d) will not work

Q.17 The use of intercooler, the COP of refrigerator will
a) increase
b) decrease
c) no effect
d) will not work

Q.18 For high compression ratio and pressure the compressor used should be
a) rotary
b) reciprocating
c) compound
d)multistage rotary

Q.19. For large volume of refrigerant and moderate pressure the compressor should be
a) rotary
b) reciprocating
c) compound
d)multistage rotary

Q.20 In vapour absorption system the absorbent used is
a) water
b) NH3
c) liquid ammonia
d) hydrogen

Q.21 In Li-Br vapour absorption system the refrigerant is
a)ammonia
b) nitrogen
c) hydrogen
d) water

Q.22 The analyser do the function to make water vapour
a) supply
b) absorb
c) condense
d) dry

Q.23 The COP of vapour absorption system compared to vapour compression system is
a) high
b) same
c) less
d) no effect

Q.24 The COP of heat pump as compared to refrigerator is
a) high
b) same
c) less
d) no effect

Q.25 The COP of heat pump is
a) 1+ COPref
b) 1- COPref
c) COPref
d) 1/ COPref

Q.26 Which contents are used to make brine solution
a) water, salt
b) water, phosphates
c) water, acid
d) water, ammonia

Q.27 Secondary refrigerants’ are used where plant size is
a) domestic
b) of large capacity
c) small
d) medium

Q.28 Dry ice is made up of
a) solid ammonia
b) solid oxygen
c) solid carbon dioxide
d) solid nitrogen

Q.29 Air refrigeration system is not much in use except in aircraft because of
a) less capacity, small size
b) less COP, large size for volume handeled
c) high COP but high power requirements
d) balancing problem and frost formation

Q.30 Ammonia is not used in domestic refrigeration system because of
a) high in flammability
b) pungent smell
c) toxicity
d) less efficient

Q.31 The hydrocarbons as refrigerants are not in use due to
a) high in flammability
b) pungent smell
c) toxicity
d) less efficient

Q.32 The chemical formula of R 12 is
a) CCF2
b)CCl2F2
c) CHF1Cl3
d) CF4

Q.33 The CFC is ozone depleting due to presence of atom of
a) C
b) H
c) F
d) Cl

Q.34 The refrigerant having non-zero ozone depletion potential is
a) R717
b) R170
c) R600
d) R14

Q.35 The wet bulb depression is the difference of
a) DBT, WBT
b) DPT, DBT
c) DPT, WBT
d) WBT, enthalpy

Q.36 The dew point depression is difference of
a) DBT, WBT
b) DPT, DBT
c) DPT, WBT
d) WBT, enthalpy

Q.37 The wet bulb temperature line are
a) parallel, equispaced
b) inclined, parallel and equispaced
c) inclined, parallel and non-equispaced
d) horizontal and parallel to each other

Q.38 The dry bulb temperature lines are
a) parallel, equispaced
b) inclined, parallel and equispaced
c) inclined, parallel and non-equispaced
d) vertical and parallel to each other

Q.39 The dew-point temperature lines are
a) parallel, equispaced
b) inclined, parallel and equispaced
c) inclined, parallel and non-equispaced
d) horizontal, equispaced and parallel to each other

Q.40 The specific volume lines are
a) parallel, equispaced
b) inclined, parallel and equispaced
c) inclined, parallel and non-equispaced
d) horizontal, equi-spaced and parallel to each other

Q.41 The expansion devices used in laboratory are of
a) capillary tube
b) thermal expansion type
c) automatic expansion valve
d) throttle valve

Q.42 The compressors used in refrigerator system are of
a) hermatically sealed type
b) vane type, centrifugal type reciprocating type

Q.43The alignment circle in psychrometric chart havin the value of
a) 26°C DBT, 50%RH
b) 25°C DBT, 60%RH
c) 25°C WBT, 60%RH
d) 25°C DBT, 100%RH

Q.44 In mixing of two air streams in air conditioning system the outlet temperature of air after mixing is
a) less than outside
b) equal to ADP
c) equal to outside
d) less than ADP

Q.45 In humidification process the humidity increases and the DBT
a) increases
b) decreases
c) same
d) first rise then decrease

Q.46 In sensible cooling the specific humidity
a) increases
b) decreases
c) same
d) first rise then decrease

Q.47 In sensible heating the DBT of air
a) increases
b) decreases
c) same
d) first rise then decrease

Q.48 In dehumidification process the humidity increases and the DBT
a) increases
b) decreases
c) same
d) first rise then decrease

Q.49 In chemical humidification the enthalpy of air
a) increases
b) decreases
c) same
d) first rise then decrease

Q.50 The agitator is used where the refrigerant used is of
a) primary
b) secondary
c) halocarbon
d) ammonia

Q.51 The bulb of psychrometer is dry then it will indicate
a) DPT
b) DBT
c) WBT
d) dry bulb depression

Q.52 If the bulb of psychrometer is surrounded by a wet wick then it will give value of
a) DPT
b) DBT
c) WBT
d) dry bulb depression


Key Solutions: 

1 (a) 2(b) 3(b) 4(a)5(a) 6(a) 7(a) 8(a) 9(b) 10(c) 11(d) 12(a) 13(c) 14(a) 15(a) 16(c) 17(a)
18(b) 19(a) 20(a) 21(d) 22(c) 23(c) 24(a) 25(a) 26(a) 27(b) 28(c) 29(b) 30(c) 31(a) 32(b)
33(d) 34(d) 35(a) 36(b) 37(b) 38(d) 39(d) 40(b) 41(a) 42(a) 43(a) 44(a) 45(c) 46(c) 47(a)
48(c) 49(c) 50(b)51(b)52(c)