Explore topic-wise MCQs in ENGINEERING SERVICES EXAMINATION (ESE).

This section includes 50 Mcqs, each offering curated multiple-choice questions to sharpen your ENGINEERING SERVICES EXAMINATION (ESE) knowledge and support exam preparation. Choose a topic below to get started.

1.

One ton of the refrigeration is

A. The standard unit used in refrigeration problems
B. The cooling effect produced by melting 1 ton of ice
C. The refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours
D. The refrigeration effect to produce 1 ton of ice at NTP conditions
Answer» D. The refrigeration effect to produce 1 ton of ice at NTP conditions
2.

 

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
3.

Highest pressure encountered in a refrigeration system should be

A. Critical pressure of refrigerant
B. Much below critical pressure
C. Much above critical pressure
D. Near critical pressure
Answer» C. Much above critical pressure
4.

In aircraft, air refrigeration Cycle is used because of

A. Low weight per tonne of refrigeration
B. High heat transfer rate
C. Low temperature at high altitudes
D. Higher coefficient of performance
Answer» B. High heat transfer rate
5.

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
Answer» E.
6.

 The pressure at the inlet of a refrigerant compressor is called

A. Suction pressure
B. Discharge pressure
C. Critical pressure
D. Back pressure
Answer» B. Discharge pressure
7.

Pick up the wrong statement. A refrigerant should have

A. Tow specific heat of liquid
B. High boiling point
C. High latent heat of vaporisation
D. Higher critical temperature
Answer» C. High latent heat of vaporisation
8.

 Hydrogen is used in Electrolux refrigeration system so as to _________ the rate of evaporation of the liquid ammonia passing through the evaporator.

A. Equalize
B. Reduce
C. Increase
D. None of these
Answer» D. None of these
9.

 If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be

A. Same
B. More
C. Less
D. More/less depending on rating
Answer» C. Less
10.

Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?

A. Ammonia
B. Carbon dioxide
C. Sulphur dioxide
D. Fluorine
Answer» E.
11.

 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
12.

The reduced ambient air cooling system has

A. One cooling turbine and one heat exchanger
B. One cooling turbine and two heat exchangers
C. Two cooling turbines and one heat exchanger
D. Two cooling turbines and two heat exchangers
Answer» D. Two cooling turbines and two heat exchangers
13.

The leaks in a refrigeration system using Freon are detected by

A. Halide torch which on detection produces greenish flame lighting
B. Sulphur sticks which on detection gives white smoke
C. Using reagents
D. Smelling
Answer» B. Sulphur sticks which on detection gives white smoke
14.

The process, generally used in winter air-conditioning to warm and humidity the air, is called

A. Humidification
B. Dehumidification
C. Heating and humidification
D. Cooling and dehumidification
Answer» D. Cooling and dehumidification
15.

One ton refrigeration corresponds to

A. 50 kcal/ min
B. 50 kcal/ hr
C. 80 kcal/ min
D. 80 kcal/ hr
Answer» B. 50 kcal/ hr
16.

During sensible heating of air _________ decreases.

A. Wet bulb temperature
B. Relative humidity
C. Dry bulb temperature
D. Specific humidity
Answer» C. Dry bulb temperature
17.

For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then

A. Bigger cabinet should be used
B. Smaller cabinet should be used
C. Perfectly tight vapour seal should be used
D. Refrigerant with lower evaporation temperature should be used
Answer» D. Refrigerant with lower evaporation temperature should be used
18.

In a vapour compression system, the condition of refrigerant before passing through the condenser is

A. Saturated liquid
B. Wet vapour
C. Dry saturated vapour
D. Superheated vapour
Answer» E.
19.

Which of the following statement is wrong?

A. The performance of the vapour compression refrigerator varies considerably with both vaporising and condensing temperatures.
B. In vapour compression cycle, the useful part of the heat transfer is at the condenser.
C. In ammonia-hydrogen (Electrolux) refrigerator, no compressor, pump or fan is required.
D. The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance
Answer» E.
20.

The vapour pressure of refrigerant should be

A. Lower than atmospheric pressure
B. Higher than atmospheric pressure
C. Equal to atmospheric pressure
D. Could be anything
Answer» C. Equal to atmospheric pressure
21.

During humidification process, dry bulb temperature

A. Remains constant
B. Increases
C. Decreases
D. None of these
Answer» B. Increases
22.

The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will

A. Increase
B. Decrease
C. Remain unaffected
D. May increase or decrease depending on the type of refrigerant used
Answer» B. Decrease
23.

The wet bulb depression is zero when relative humidity is

A. Zero
B. 0.5
C. 0.75
D. 1.0
Answer» E.
24.

At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant

A. Decreases
B. Increases
C. Remain same
D. Depends on other factors
Answer» C. Remain same
25.

During sensible cooling of air ________ decreases.

A. Wet bulb temperature
B. Relative humidity
C. Dry bulb temperature
D. Specific humidity
Answer» D. Specific humidity
26.

The moisture in a refrigerant is removed by

A. Evaporator
B. Safety relief valve
C. Dehumidifier
D. Driers
Answer» E.
27.

The refrigerant widely used in domestic refrigerators is

A. Ammonia
B. Carbon dioxide
C. Sulphur dioxide
D. R-12
Answer» E.
28.

During dehumidification process, the relative humidity

A. Remains constant
B. Increases
C. Decreases
D. None of these
Answer» D. None of these
29.

Rick up the incorrect statement

A. Lithium bromide used in vapour absorption cycle is non volatile
B. Lithium bromide plant cant operate below 0°C
C. A separator is used in lithium bromide plant to remove the unwanted water vapour by condensing
D. Concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator
Answer» D. Concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator
30.

The centrifugal compressors are generally used for refrigerants that require

A. Small displacements and low condensing pressures
B. Large displacements and high condensing pressures
C. Small displacements and high condensing pressures
D. Large displacements and low condensing pressures
Answer» E.
31.

An important characteristic of absorption system of refrigeration is

A. Noisy operation
B. Quiet operation
C. Cooling below 0°C
D. Very little power consumption
Answer» C. Cooling below 0°C
32.

 

The condition of refrigerant after passing through the expansion or throttle valve, in a vapour compression system is
 

A. High pressure saturated liquid
B. Wet vapour
C. Very wet vapour
D. Dry vapour
Answer» D. Dry vapour
33.

Domestic refrigerator working on vapour compression cycle uses the following type of expansion device

A. Electrically operated throttling valve
B. Manually operated valve
C. Thermostatic valve
D. Capillary tube
Answer» E.
34.

The fluids used in Electrolux refrigerator are

A. Water and hydrogen
B. Ammonia and hydrogen
C. Ammonia, water and hydrogen
D. None of these
Answer» D. None of these
35.

The COP of a vapour compression plant in comparison to vapour absorption plant is

A. More
B. Less
C. Same
D. More/less depending on size of plant
Answer» B. Less
36.

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
37.

In a lithium bromide absorption refrigeration system

A. Lithium bromide is used as a refrigerant and water as an absorbent
B. Water is used as a refrigerant and lithium bromide as an absorbent
C. Ammonia is used as a refrigerant and lithium bromide as an absorbent
D. None of the above
Answer» C. Ammonia is used as a refrigerant and lithium bromide as an absorbent
38.

The bank of tubes at the back of domestic refrigerator is

A. Condenser tubes
B. Evaporator tubes
C. Refrigerant cooling tubes
D. Capillary tubes
Answer» B. Evaporator tubes
39.

A human body feels comfortable when the heat produced by the metabolism of human body is equal to the

A. Heat dissipated to the surroundings
B. Heat stored in the human body
C. Sum of (A) and (B)
D. Difference of (A) and (B)
Answer» D. Difference of (A) and (B)
40.

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
41.

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
42.

The vapour compression refrigerator employs the following cycle

A. Rankine
B. Carnot
C. Reversed Rankine
D. Reversed Carnot
Answer» E.
43.

In a refrigeration system, the expansion device is connected between the

A. Compressor and condenser
B. Condenser and receiver
C. Receiver and evaporator
D. Evaporator and compressor
Answer» D. Evaporator and compressor
44.

Mass flow ratio of NH₃ in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order ofa

A. 1: 1
B. 1: 9
C. 9: 1
D. 1: 3
Answer» C. 9: 1
45.

The freezing point of sulphur dioxide is

A. -56.6°C
B. -75.2°C
C. -77.7°C
D. -135.8°C
Answer» C. -77.7°C
46.

Cooling water is required for following equipment in ammonia absorption plant

A. Condenser
B. Evaporator
C. Absorber
D. Condenser, absorber and separator (rectifier)
Answer» E.
47.

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
48.

For obtaining high COP, the pressure range of compressor should be

A. High
B. Low
C. Optimum
D. Any value
Answer» C. Optimum
49.

The boiling point of ammonia is

A. -10.5°C
B. -30°C
C. -33.3°C
D. -77.7°C
Answer» D. -77.7°C
50.

Freon group of refrigerants are

A. Inflammable
B. Toxic
C. Non-inflammable and toxic
D. Nontoxic and non-inflammable
Answer» E.