Compressors, Gas Turbines and Jet Engines - Mechanical Engineering Multiple choice Questions and Answers

Compressors, Gas
Turbines and Jet Engines -
Mechanical Engineering Multiple
choice Questions and Answers

1. Free air is the air at
(a) atmospheric conditions at any specific location
(b) 20°C and 1 kg/cm2 and relative humidity of 36%
(c) 0°C and standard atmospheric conditions
(d) 15°C and 1 kg/cm2
(e) 25°C, 1 kg/cm2 and relative humidity of 50%.
Ans: a
2. Standard air is the air at
(a) atmospheric conditions at any specific location
(b) 20°C and 1 kg/cm2 and relative humidity 36%
(c) 0°C and standard atmospheric conditions
(d) 15°C and 1 kg/cm2
(e) 25°C, 1 kg/cm2 and RH of 60%.
Ans: b
3. 1 m of air at atmospheric condition weighs
approximately
(a) 0.5 kg
(b) 1.0 kg
(c) 1.3 kg
(d) 2.2 kg
(e) 3.2 kg.
Ans: c
4. Adiabatic compression is one in which
(a) temperature during compression remains
constant
(b) no heat leaves or enters the compressor
cylinder during cornpression
(c) temperature rise follows a linear relationship
(d) work done is maximum
(e) entropy decreases.
Ans: b
5. The capacity of a compressor is 5 m /mih. 5 m /
min refers to
(a) standard air
(b) free air
(c) compressed air
(d) compressed air at delivery pressure
(e) air sucked.
Ans: b
6. The overall isothermal eiffciency of compressor
is defined as the ratio of
(a) isothermal h.p. to the BHP of motor
(b) isothermal h.p. to adiabatic h.p.
(c) power to drive compressor to isothermal h.p.
(d) work to compress air isothermally to work for
actual compression
(e) isothermal work to ideal work.
Ans: a
7. The- most efficient method of compressing air is
to compress it
(a) isothermally
(b) adiabatically
(c) isentropically
(d) isochronically
(e) as per law pV
Ans: a
8. Maximum work is done in compressing air when
the compression is
(a) isothermal
(b) adiabatic
(c) polytropic
(d) any one of the above
(e) none of the above.
Ans: b
9. The pressure and temperature conditions of air at
the suction of compressor are
(a) atmospheric
(b) slightly more than atmospheric
(c) slightly less than atmospheric
(d) pressure slightly more than atmospheric and
temperature slightly less than atmospheric
(e) pressure sightly less than atmospheric and
temperature slightly more than atmospheric.
Ans: e
10. Isothermal compression effeicency can be
attained by running the compressor
(a) at very high speed
(b) at very slow speed
(c) at average speed
(d) at zero speed
(e) isothermally.
Ans: b
11. The compressor capacity with decrease in
suction temperature
(a) increases
(b) decreases
(c) remains unaffected
(d) may increase or decrease depending on
compressor capacity
(e) increases upto certain limit and then decreases.
Ans: a
12. Isothermal compression efficiency, even when
running at high speed, can be approached by using
(a) multi-stage compression
(b) cold water spray
(c) both (a) and (b) above
(d) fully insulating the cylinder
(e) high stroke.
Ans: c
13. Compression efficiency is compared against
(a) ideal compression
(b) adiabatic compression
(c) botii isothermal and adiabatic compression
(d) isentropic compression
(e) isothermal compression.
Ans: e
14. Aeroplanes employ following type of
compressor
(a) radial flow
(b) axial flow
(c) centrifugal
(d) combination of above
(e) none of the above.
Ans: b
15. Inter cooling in compressors
(a) cools the delivered air
(b) results in saving of power in compressing a
given volume to given pressure
(c) is the standard practice for big compressors
(d) enables compression in two stages
(e) prevents compressor jacket running very hot.
Ans: b
16. An ideal air compressor cycle without clearance
on p-v diagram can be represented by following
processes
(a) one adiabatic, two isobaric, and one constant
volume
(b) two adiabatic and two isobaric
(c) two adiabatic, one isobaric and one constant
volume
(d) one adiabatic, one isobaric  and two constant
volume
(e) two isobaric,  two adiabatic and one constant
volume.
Ans: a
17. An ideal air compressor cycle with clearance on
p-v diagram can be represented by following
processes
(a) one adiabatic, two isobaric, and one constant
volume
(b) two adiabatic and two isobaric
(c) two adiabatic, one isobaric  and one constant
volume,
(d) one adiabatic, one isobaric and two constant
volume
(e) two isobaric, two adiabatic and one constant
volume.
Ans: b
18. What will be the volume of air at 327°C if its
volume at 27°C is 1.5 m3/mt
(a)  3 m3/mt .
(b)  1.5 m3/mt
(c) 18 m3/mt'
(d)  6 m3/mt
(e)  0.75 m3/mt.
Ans: a
19. The work done per unit mass of air in
compression will'be least when n is equal to
(a) 1
(b) 1.2 ,
(c) 1.3
(d) 1.4
(e) 1.5
Ans: a
20. Isothermal compression though most efficient,
but is not -practicable because
(a) ityrequires very big cylinder
(b) it does not increase pressure much
(c) it is impossible in practice
(d) compressor has to run at very slow speed to
achieve it
(e) it requires cylinder to be placed in water.
Ans: d
21. Ratio of indicated H.P. and brake H.P. is known
as
(a) mechanical efficiency
(b) volumetric efficiency
(c) isothermal efficiency
(d) adiabatic efficiency
(e) relative efficiency.
Ans: a
22. The ratio of work doen per cycle to the swept
volume in case of compressor is called
(a) compression index
(b) compression ratio
(c) compressor efficiency
(d) mean effective pressure
(e) compressor effectiveness.
Ans: d
23. Cylinder clearance in a compressor should be
(a) as large as possible
(b) as small as possible
(c) about 50% of swept volume
(d) about 100% of swept volume
(e) none of the above.
Ans: b
24. Ratio of compression is the ratio of
(a) gauge discharge pressure to the gauge intake
pressure
(b) absolute discharge pressure to the ab-solute
intake pressure
(c) pressures at discharge and suction cor-
responding to same temperature
(d) stroke volume and clearance volume
(e) none of the above.
Ans: b
25. Clearance volume in actual reciprocating
compressors is essential
(a) to accommedate Valves in the cylinder head
(b) to provide cushioning effect
(c) to attain high volumetric efficiency
(d) to avoid mechanical bang of piston with cylinder
head
(e) to provide cushioning effect and also to avoid
mechanical bang of piston with cylinder head.
Ans: e
26. The net work input required for compressor with
increase in clearance volume
(a) increases
(b) decreases
(c) remains same
(d) increases/decreases depending on com-
pressor capacity
(e) unpredictable.
Ans: c
27. Ratio of indicated h.p. to shaft h.p. in known as
(a) compressor efficiency
(b) isothermal efficiency
(c) volumetric efficiency
(d) mechanical efficiency
(e) adiabatic efficiency.
Ans: d
28. Volumetric efficiency is
(a) the ratio of stroke volume to clearance volume
(b) the ratio of the air actually delivered to the
amount of piston displacement
(c) reciprocal of compression ratio
(d) index of compressor performance
(e) proportional to compression ratio.
Ans: b
29. Volumetric efficiency of air compressors is of
the order of
(a) 20-30%
(b) 40-50%
(c) 60-70%
(d) 70-90%
(e) 90-100%.
Ans: d
30. Volumetric efficiency of a compressor with
clearance volume
(a) increases with increase in compression ratio
(b) decreases with increase in compression ratio
(c) in not dependent upon compression ratio
(d) may increase/decrease depending  on
compressor capacity
(e) unpredictable.
Ans: b
31. Volumetric efficiency of a compressor without
clearance volume
(a) increases with increase in compression ratio
(b) decreases with increase in compression ratio
(c) is not dependent upon compressin ratio
(d) may increase/decrease depending on
compressor capacity
(e) unpredictable.
Ans: c
32. The clearance volume of the air compressor is
kept minimum because
(a) it allows maximum compression to be achieved
(b) it greatly affects volumetric efficiency
(c) it results in minimum work
(d) it permits isothermal compression
(e) none of the above.
Ans: b
33. Euler's equation is applicable for
(a) centrifugal compressor
(b) axial compressor
(c) pumps
(d) all of the above
(e) none of the above.
Ans: d
40. Out of the following, from where you will prefer
to take intake for air compressor
(a) from an air conditioned room maintained at 20°C
(b) from outside atmosphere at 1°C
(c) from coal yard side
(d) from a side where cooling tower is located
nearby
(e) from any one of the above locations.
Ans: d
41. Mining industry usually employs following
motive power
(a) A.C. electric motor
(b) compressed air
(c) petrol engine
(d) diesel engine
(e) D.C. electric motor.
Ans: b
42. Which is false statement about air receivers
(a) These are used to dampen pulsations ,
(b) These act as reservoir to- take care of sudden
demands
(c) These increase compressor efficiency
(d) These knock out some oil and moisture
(e) These reduce frequent on/off operation of
compressors.
Ans: c
44. An air receiver is to be placed outside. Should it
be placed in
(a) sun
(b) shade
(c) rain
(d) enclosed room
(e) anywhere.
Ans:
45. Which is false statement about multistage
compression .
(a) Power consumption per unit of air delivered is
low
(b) Volumetric efficiency is high
(c) It is best suited for compression ratios around
7:1
(d) The moisture in air is condensed in the
intercooler
(e) Outlet temperature is reduced.
Ans: b
46. In multistage compressor, the isothermal
compression is achieved by
(a) employing intercooler
(b) by constantly cooling the cylinder
(c) by running compressor at very slow speed
(d) by insulating the cylinder
(e) none of the above.
Ans: c
47. Reciprocating air compressor is best suited for
(a) large quantity of air at high pressure
(b) small quantity of air at high pressure
(c) small quantity of air at low pressure
(d) large quantity of air at low pressure
(e) any one of the above.
Ans: a
48. Rotary compressor is best suited for
(a) large quantity of air at high pressure
(b) small quantity of air at high pressure
(c) small quantity of air at low pressure
(d) large quantity of air at low pressure
(e) any one of the above.
Ans: b
49. The capacity of compressor will be highest
when its intake temperature is
(a) lowest
(b) highest
(c) anything.
(d) atmospheric
(e) none of the above.
Ans: d
50. After-cooler is used to
(a) cool the air
(b) decrease the delivery temperature for ease in
handling
(c) cause moisture and oil vapour to drop out
(d) reduce volume
(e) increase pressure.
Ans: c
51. To aviod moisture troubles, the compressed air
main line should
(a) rise gradually towards the point of use
(b) drop gradually towards the point of use
(c) be laid vertically
(d) be laid exactly horizontally
(e) none of the above
Ans: b
52. Separators in compressor installations are
located
(a) before intercooler
(b) after intercooler
(c) after receiver
(d) between after-cooler and air receiver
(e) before suction.
Ans: d
53. The area of actual indicator diagram on an air
compressor as compared to area of ideal indicator
diagram is
(a) less
(b) more
(c) same
(d) more/less depending on compressor capacity
(e) unpredictable.
Ans: b
54. An air compressor may be controlled by
(a) throttle control (b) clearance control
(c) blow-off control
(d) any one of the above
(e) none of the above.
Ans: d
55. The compressor efficiecny is the
(a) isothermal H.P/indicated H.R
(b) isothermal H.P./shaft H.R
(c) total output/air input
(d) compression work/motor input
(e) none Of the above.
Ans: a
56. To avoid moisture troubles, the branch
connections from compressed air lines should be
taken from
(a) top side of main
(b) bottom side of main
(c) left side of main
(d) right side of main
(e) any location.
Ans: a
57. The thrust on the rotor in a centrifugal
compressor is produced by
(a) radial component
(b) axial component
(c) tangential component
(d) resultant component
Ans: b
58. The compressor performance at higher altitude
compared to sea level will be
(a) same
(b) higher
(c) lower
(d) dependent on other factors
(e) none of the above.
Ans: c
59. A compressor at high altitude will draw
(a) more power
(b) less power
(c) same power
(d) more/less power depending on other factors
(e) none of the above.
Ans: b
60. During peak load periods, the best method of
controlling compressors is
(a) start-stop motor
(b) constant speed unloader
(c) relief valve
(d) variable speed
(e) none of the above.
Ans: b
61. A centrifugal compressor works on the principle
of
(a) conversion of  pressure energy into kinetic
energy
(b) conversion of kinetic energy into pres¬sure
energy
(c) centripetal action
(d) generating pressure directly
(e) combination of (a) and (d).
Ans: b
62. For a compressor, least work will be done if the
compression is
(a) isentropic
(b) isothermal
(c) polytropic
(d) somewhere in between isentropic and
isothermal
(e) none of the above.
Ans: b
67. In a compressor, free air delivered is the actual
volume delivered at the stated pressure reduced to
(d) N.T.P. conditions
(b) intake temperature and pressure conditions
(c) 0°C and 1 kg/cm2
(d) 20°C and 1 kg/cm2
(e) none of the above.
Ans: b
68. The volumetirc efficiency of a compressor is
calculated on the basis of
(a) volume of air inhaled at working conditions
(b) volume of air inhaled at N.T.P. conditions
(c) volume at 0°C and 1 kg/cm2
(d) volume at 20°C and 1 kg/cm2
(e) none of the above.
Ans: b
69. The volumetric efficiency of a compressor falls
roughly as follows for every 100 m increase in
elevation
(a) 0.1%
(b) 0.5%
(c) 1.0%
(d) 5%
(e) 10%.
Ans: c
70. For slow-speed large capacity compressor,
following type of valve will be best suited
(a) poppet valve
(b) mechanical valve of the corliss, sleeve, rotary or
semirotary type
(c) disc or feather type
(d) any of the above
(e) none of the above.
Ans: c
71. During base load operation, the best method of
controlling compressor is
(a) start-stop motor
(b) constant speed unloader
(c) relief valve
(d) variable speed
(e) none of the above.
Ans: a
72. More than one stage will be preferred for
reciprocating compressor if the delivery pressure is
more than
(a) 2 kg/cm2
(b) 6 kg/cm2
(c) 10 kg/cm2
(d) 14.7 kg/cm2
(e) none of the above.
Ans: a
73. The advantage of multistage compression over
single stage compression is
(a) lower power consumption per unit of air
delivered
(b) higher volumetric efficiency
(c) decreased discharge temperature
(d) moisture free air
(e) all of the above.
Ans: e
74. Pick up the wrong statement about advantages
of multistage compression
(a) better lubrication is possible advantages of
multistage
(b) more loss of air due to leakage past the cylinder
(c) mechanical balance is better
(d) air can be cooled perfectly in between
(e) more uniform torque, light cylinder and saving in
work.
Ans: b
75. As the value of index '«' is decreased, the
volumetric efficiency will
(a) increase
(b) decrease
(c) remain unaffected
(d) may increase/decrease depending on
compressor clearance
(e) none of the above.
Ans: b
76. The ratio of outlet whirl velocity to blade velocity
in case of centrifugal compressor is called
(a) slip factor
(b) velocity factor
(c) velocity coefficient
(d) blade effectiveness
Ans: a
79. Losses in a centrifugal compressor are due to
(a) inlet losses
(b) impeller channel losses
(c) diffuser losses
(d) all of the above
(e) none of the above
Ans: d
80. The volumetric efficiency of a compressor falls
roughly as follows for every 5°C increase in
atmospheric temperature
(a) 0.1%
(b) 0.5%
(c) 1%
(d) 5%
(e ) 10%.
Ans: c
81. The indicated work per unit mass of air
delivered is
(a) directly proportional to clearance volume
(b) greatly affected by clearance volume
(c) not affected by clearance volume
(d) inversely proportional to clearance volume
Ans: c
89. For actual single stage centrifugal compressor,
the maximum pressure ratio is of the order of
(a) 1 : 1.2
(b) 1 : 2
(c) 1 : 4
(d) 1 : 10
(e) 1 : 1
Ans:
90. Which is false statement about advantages of
multistage compressor in comparison to single
stage compressor
(a) less power requirement
(b) better mechanical balance
(c) less loss of air due to leakage past the cylinder
(d) more effective lubrication
(e) lower volumetric efficiency.
Ans: e
91. The ratio of isentropic work to Euler work is
known as
(a) pressure coefficient
(b) work coefficient
(c) polytropic reaction
(d) slip factor
(e) compressor efficiency.
Ans: a
92. The criterion of the thermodynamic efficiency for
rotary compressor is
(a) isentropic compression
(b) isothermal compression
(c) polytropic compression
(d) any one of the above
(e) none of the above.
Ans: a
93. For supplying intermittent small quantity of air at
high pressure, following compressor is best suited
(a) centrifugal
(b) reciprocating
(c) axial
(d) screw
(e) turbo jet.
Ans: b
94. For minimum work in multistage compression,
assuming same index of compression in all stages
(a) work done in first stage should be more
(b) work done in subsequent stages should
increase
(c) work done in subsequent stages should
decrease
(d) work done in all stages should be equal
(e) work done in any stage is no criterion for
minimum work but depends on other factors.
Ans: d
95. For a two stage compressor* if index of
compression for higher stage is greater than index
of compression for lower stage, then the optimum
pressure as compared to ideal case will
(a) increase
(b) decrease
(c) remain unaffected
(d) other factors control it
(e) unpredictable.
Ans: a
96. Diffuser in a compressor is used to
(a) increase velocity
(b) make the flow stream-line
(c) convert pressure energy into kinetic energy
(d) convert kinetic energy into pressure energy
(e) increase degree of reaction.
Ans: d
98. The ratio of isentropic work to euler's work is
known as
(a) compressor efficiency
(b) isentropic efficiency
(c) Euler's efficiency
(d) pressure coefficient
(e) pressure ratio.
Ans: d
99. The thermodynamic efficiency of rotary
compressor is based on
(a) isothermal compression
(b) adiabatic compression
(c) isentropic compression
(d) polytropic compression
(e) none of the above.
Ans: b
100. Phenomenon of choking in compressor means
(a) no flow of air
(b) fixed mass flow rate regardless of pressure
ratio
(c) reducing mass flow rate with increase in
pressure ratio
(d) increased inclination of chord with air steam
(e) does not occur.
Ans: b
101. The maximum compression ratio in an actual
single stage axial flow comperssor is of the order of
(a) 1 : 1.2
(b) 1 : 2
(c) 1 : 5
(d) 1 : 10
(e) 1 : 1
Ans: a
102. Maximum delivery pressure is a rotary air
compressor is of the order of
(a) 6 kg/cm2
(b) 10 kg/cm2
(c) 16 kg/cm2
(d) 25 kg/cm2
(e) 40 kg/cm2.
Ans: b
103. Surging is the phenomenon of
(a) air stream blocking the passage
(b) motion of air at sonic velocity
(c) unsteady, periodic and reversed flow
(d) air stream not able to follow the blade contour
(e) production of no air pressure.
Ans: c
104. Pick up wrong statement.
Surging phenomenon in centrifugal com-pressor
depends on
(a) mass flow rate
(b) pressure ratio
(c) change in load
(d) stagnation pressure at the outlet
(e) all of the above.
Ans: d
105. The ratio of the increase in pressure in rotor
blades to total increase in pressure in the stage is
called
(a) pressure ratio
(b) pressure coefficient
(c) degree of reaction
(d) slip factor
(e) stage factor.
Ans: c
106. Axial flow compressor resembles
(a) centrifugal pump
(b) reciprocating pump
(c) turbine
(d) sliding vane compressor
(e) none of the above.
Ans: c
107. Axial flow compressor has the following
advantage over centrifugal compressor
(a) larger air handling  ability  per unit frontal area
(b) higher pressure ratio per stage
(c) aerofoil blades are used
(d) higher average velocities
(e) none of the above.
Ans: a
108. Actual compression curve is
(a) same as isothermal
(b) same as adiabatic
(c) better than isothermal and adiabatic
(d) in between isothermal and adiabatic
(e) none of the above.
Ans: d
109. Atmospheric pressure is 1.03 kg/cm and
vapour pressure is 0.03 kg/cm . The air pressure
will be
(a) 1.03 kg/cm2
(b) 1.06 kg/cm2
(c) 1.00 kg/cm2
(d) 0.53 kg/cm2
(e) 0.5 kg/cm2.
Ans: c
110. The pressure ratio of an ideal vaned
compressor with increase in mass flow rate
(a) increases
(b) decreases
(c) remains constant
(d) first decreases and then increases
(e) unpredictable.
Ans: c
111. Rotary compressors are suitable for
(a) large discharge at high pressure
(b) low discharge at high pressure
(c) large discharge at low pressure
(d) low discharge at low pressure
(e) there is no such limitation.
Ans: c
112. The vloumetric efficiency of compressor with
increase in compression ratio will
(a) increase
(b) decrease
(c) remain same
(d) may increase/decrease depending on clearance
volume
(e) none of the above.
Ans: b
113. Stalling of blades in axial flow compressor is
the phenomenon of
(a) air stream blocking the passage
(b) motion of air at sonic velocity
(c) unsteady periodic and reversed flow
(d) air stream not able to follow the blade contour
(e) production of no air pressure.
Ans: d
114. Pick up the wrong statement
(a) centrifugal compressors deliver prac-tically
constant pressure over a considerable range of
capacities
(b) Axial flow compressors have a sub-stantially
constant delivery at variable pressures
(c) centrifugal compressors have a wider stable
operating range than axial flow compressors
(d) axial flow compressors are bigger in diameter
compared to centrifugal type
(e) axial flow compressors apt to be longer as
compared to centrifugal type.
Ans: d
115. The work ratio of a gas turbine plant is defined
as the ratio of
(a) net work output and heat supplied (6) net work
output and work done by tur¬bine
(c) actual heat drop and isentropic heat drop
(d) net work output and isentropic heat drop
(e) isentropic increase/drop in tempera¬ture and
actual increase/ drop in temperature.
Ans: b
116. Gas turbine works on
(a) Brayton or Atkinson cycle
(b) Carnot cycle
(c) Rankine cycle
(d) Erricsson cycle
(e) Joule cycle.
Ans: a
117. The work ratio of simple gas turbine cycle
depends on
(a) pressure ratio
(b) maximum cycle temperature
(c) minimum cycle temperature
(d) all of the above
(e) none of die above.
Ans: d
118. The pressure ratio for an open cycle gas
turbine compared to closed cycle gas turbine of
same h.p. is
(a) low
(b) high
(c) same
(d) low/high depending on make and type
(e) unpredictable.
Ans: a
119. Open cycle gas turbine works on
(a) Brayton or Atkinson cycle
(6) Rankine cycle
(c) Carnot cycle
(d) Erricsson cycle
(e) Joule cycle.
Ans: a
120.  The fuel consumption in gas turbines is
accounted for by
(a) low.er heating value
(b) higher heating value
(c) heating value
(d) higher calorific value
(e) highest calorific value.
Ans: a
121. Gas turbines for power generaion are normally
used
(a) to supply base load requirements
(b) to supply peak load requirements
(c) to enable start thermal power plant
(d) in emergency
(e) when other sources of power fail.
Ans: b
122. Mechanical efficiency of gas turbines as
compared to I.C engines is
(a) higher
(b) lower
(c) same
(d) depends on on odier considerations
(e) unpredictable.
Ans: a
123. The ratio of specific weighf/h.p. of gas turbin
and I.C engines may be typically of the order of
(a) 1 : 1
(b) 2 : 1
(c) 4 : 1
(d) 1:2
(e) 1 : 6.
Ans: e
124. The thermal efficiency of a gas turbine as
compared to a diesel plant is
(a) same
(b) more
(c) less
(d) depends on other factors
(e) unpredictably.
Ans: c
125. The air-fuel ratio in gas turbines is of the order
of
(a) 7 : 1
(b) 15 : 1
(c) 30 : 1
(d) 40 : 1
(e) 50: 1.
Ans: e
126. The pressure ratio in gas turbines is of the
order of
(a),2:l
(b)4:1
(c) 61: 1
(d) 9 : 1
(e) 12:1.
Ans: c
128. The hottest point in a gas turbine is
(a) at the base
(b) at the tip
(c) in the center
(d) between ~ to i of the blade height
(e) uniformly heated.
Ans: d
129. The following is true for an open cycle gas
turbine having exhaust heat exchanger.
Atmospheric air before entering the compressor is
(a) heated
(b) compressed air before entering the combustion
chamber is heated
(c) bled gas from turbine is heated and readmitted
for complete expansion
(d) exhaust gases drive the compressor
(e) part of exhaust gases are heated and mixed up
with atmospheric air to utilise exhaust heat.
Ans: b
130. Gas turbine blades are given a rake
(a) equal to zero
(b) in the direction of motion of blades
(c) opposite to the direction of motion of blades
(d) depending on the velocity
(e) none of the above.
Ans: b
131. Efficiency of gas turbine is increased by
(a) reheating
(b) inter cooling
(c) adding a regenerator
(d) all of the above
(e) none of the above.
Ans: c
132. Temperature of gases at end of compression
as compared to exhaust gases in a gas turbine is
(a) higher
(b) lower
(c) equal
(d) can't be compared
(e) unpredictable.
Ans: b
133. The ideal efficiency of simple gas turbine cycle
depends on
(a) pressure ratio
(b) maximum cycle temperature
(c) minimum cycle temperature
(d) all of the above
(e) none of the above.
Ans: a
134. The thermal efficiency of a simple gas turbine
for a given turbine inlet temperature with increase
in pressure ratio
(a) increases
(b) decreases
(c) first increases and then decreases
(d) first decreases and then increases
(e) remains same.
Ans: a
135. Gas turbines use following type of air
compressor
(a) centrifugal type
(b) reciprocating type
(c) lobe type
(d) axial flow type
(e) none of the above.
Ans: d
136. As the turbine inlet temperature increases, the
thermal efficiency of gas turbine for the optimum
pressure ratio
(a) increases
(b) decreases
(c) remains same
(d) first increases and then decreases
(e) first decreases and then increases.
Ans: a
137. There is a certain pressure ratio (optimum) for
a gas turbine at which its thermal efficiency is
maximum. With increase in turbine temperature, the
value of pressure ratio for the peak efficiency would
(a) remain same
(b) decrease
(c) increase
(d) unpredictable
(e) none of the above.
Ans: c
138. The material commonly used for air craft gas
turbine is
(a) stainless steel
(b) high alloy' steel
(c) duralumin
(d) Timken, Haste and Inconel allpys
(e) titanium.
Ans: d
139. It is not possible to use closed gas turbine
cycle in aeronautical engines because
(a) it is inefficient
(b) it is bulky
(c) it requires cooling water for its operation
Ans: c
140. The combustion efficiency of a gas turbine
using perfect combustion chamber is of the order of
(a) 50%
(b) 75%
(c) 85%
(d) 90%
(e ) 99%.
Ans: e
141. The jnaximum combustion pressure in gas
turbine as compared to I.C. engine is
(a) more
(b) less
(c) same
(d) depends on other factors
(e) unpredictable.
Ans: b
142. For an irreversible gas turbine cycle, the
efficiency and work ratio both depend on
(a) pressure ratio alone
(b) maximum cycle temperature alone
(c) minimum cycle temperature alone
(d) both pressure ratio and maximum cycle
temperature
(e) none of the above.
Ans: d
143. Producer gas is produced by
(a) carbonisation of coal
(b) passing steam over incandescent coke
(c) passing air and a large amount of steam over
waste coal at about 65°C
(d) partial combustion of coal, coke, anthracite coal
or charcoal in a mixed air steam blast
(e) same way as the natural gas.
Ans: d
144. Water gas is produced by
(a) carbonisation of coal
(b) passing steam over incandescent coke
(c) passing air and a large amount of steam over
waste coal at about 65°C
(d) partial combustion of caol, eke, anthractie coal
or charcoal in a mixed air steam blast
(e) same way as the natural gas.
Ans: b
14 Water is injected in gas turbine cycle to
(a) control temperature
(b) control output of turbine
(c) control fire hazards
(d) increase efficiency
(e) it is never done.
Ans: b
146. A gas turbine used in air craft should have
(a) high h.p. and low weight
(b) low weight and small frontal area
(c) small frontal area and high h.p.
(d) high speed and high h.p.
(e) all of the above.
Ans: b
148. The closed cycle in gas turbines
(a) provides greater flexibility
(b) provides lesser flexibility
(c) in never used
(d) is used when gas is to be burnt
(e) none of the above.
Ans: a
149. In the axial flow gas turbine, the work ratio is
the ratio of
(a) compressor work and turbine work
(b) output and input
(c) actual total head tempeature drop to the
isentrpic total head drop from total head inlet to
static head outlet
(d) actual compressor work and theoretical
comprssor work
(e) none of the above.
Ans: c
150. The degree of reaction of an axial flow turbine
is the ratio of isentropic temperature drop in a blade
row to the
(a) adiabatic temperature drop in the stage
(b) total temperature drop
(c) total temperature drop in the stage
(d) total adiabaitc temperature drop
(e) difference of maximum and minimum
temperature in the cycle.
Ans: c
153. If infinite number of heaters be used in a gas
turbine, then expansion process in turbine
approaches
(a) isothermal
(b) isentropic
(c) adiabatic
(d) isochoric
(e) isobaric.
Ans: a
154. Pick up the correct statement
(a) gas turbine uses low air-fuel ratio to economise
on fuel
(b) gas turhine uses high air-fuel ratio to reduce
outgoing temperature
(c) gas turbine uses low air-fuel ratio to develop the
high thrust required
(d) all of the above
(e) none of the above.
Ans: b
15 Intercooling in gas turbine results in
(a) increase in net output but decrease in thermal
efficiency
(b) increase in thermal  efficiency but decrease
in net output
(c) increase in both thermal efficiency and net
output
(d) decrease in both thermal efficiency and net
output
(e) none of the above.
Ans: a
156. If V, U and Vr represent the absolute velocity
of fluid, velocity of blade, and relative velocity of
fluid, and suffix i and o stand for entry and exit
conditions, then in a rotary machine whose degree
of reaction is unity
(a)Vi=V0
(b)Vt>V0
(c) U,<V0
(d)V,= U0
(e) Vri=Vm.
Ans: a
157. Pick up the wrong statement
(a) large gas turbines employ axial flow
compressors
(b) axial flow compressors are more stable than
centrifugal type compressors but not as efficient
(c) axial flow compressors have high capacity and
efficiency
(d) axial flow compressors have instability
region of operation
(e) centrifugal compressors are used mainly on low
flow pressure ratio gas turbines.
Ans: b
158. The power available for take off and climb in
case of turbojet engine as compared to
reciprocating engine is
(a) less
(b) more
(c) same
(d) may be less or more depending on ambient
conditons
(e) unpredictable.
Ans: a
159. Pick up the correct statement
(a) large gas turbines use radial inflow turbines
(b) gas turbines have their blades similar to steam
turbine
(c) gas .turbine's blade will appear as impulse
section at the hub and as a reaction section at tip
(d) gas turbines use both air and liquid cooling
(e) all of the above are correct.
Ans: c
160. A closed gas turbine in which fuel is burnt
directly in the air is not possible because of
(a) high pressure ratio
(b) increasing gas temperature
(c) high specific volume
(d) high friction losses
(e) paucity of 02.
Ans: e

Steam Boilers, Engines, Nozzles and Turbines - Mechanical Engineering MCQs

Steam Boilers, Engines, Nozzles and Turbines -
Multiple Choice Questions and Answers

1. For water, at pressures below
atmospheric,
(a) melting point rises slightly and boiling
point drops markedly
(b) melting point rises markedly and boiling
point drops markedly
(c) melting point drops slightly and boiling
point drops markedly
(d) melting point drops slightly and boiling
point drops slightly
(e) none of the above.
Ans: a
2. At very low temperature, the melting
and boiling temperatures become equal. This
temperature is
(a) 373°K
(b) 273.16°K
(c) 303°K
(d) 0°K.
(e) 300°K.
Ans: b
3. The critical pressure at which latent
heat of vaporisation is zero is
(a) 225.65 kgf/cm2
(b) 273 kgf/cm2
(c) 100 kgf/cm2
(d) 1 kgf/cm2
(e) - 1 kgf/cm2.
Ans: a
4. The latent heat of steam at pressures
greater than atmospheric in comparison to latent
heat at atmospheric pressure is
(a) less
(b) more
(c) equal
(d) may be less or more depending on
temperature
(e) unpredictable.
Ans: a
5. The saturation temperature of steam
with increase in pressure increases
(a) linearly
(b) rapidly first and then slowly
(c) slowly first and then rapidly
(d) inversely
(e) none of the above.
Ans: b
6. Carbonisation of coal is the process of
(a) pulverising coal in inert atmosphere
(b) heating wood in a limited supply of air
at temperatures below 300°C
(c) strongly heating coal continuously for
about 48 hours in the absence of air in a closed
vessel
(d) binding the pulverised coal into brick-
ettes
(e) enriching carbon in the coal.
Ans: c
7. Coke is produced by
(a) pulverising coal in inert atmosphere
(b) heating wood in a limited supply of air
at temperatures below 300GC
(c) strongly heating coal continuously for
about 48 hours in the absence of air in a closed
vessel
(d) binding the pulverised coal into brick-
etts
(e) enriching carbon in the coal.
Ans: c
8. Heating of dry steam above saturation
temperature is known as
(a) enthalpy
(b) superheating
(c) supersaturation
(d) latent heat
(e) super tempering.
Ans: b
9. Superheating of steam is done at
(a) constant volume
(b) constant temperature
(c) constant pressure
(d) constant entropy
(e) constant enthaply.
Ans: c
10. 1 kg.m is equal to
(a) 9.81 Joules
(b) All Joules
(c) 427 Joules
(d) 102 Joules
(e) 539 Joules.
Ans: a
11. If partial pressure of air and steam be
pa andps respectively in a condenser, then
according to Dalton's law, the pressure in
condenser is equal to
(a) Ps-Pa
(b) pa-ps
(C) Pa+P,
Ans: c
12. Equivalent evaporation is the amount of
water evaporated in a boiler from and at
(a) 0°C
(b) 100°C
(c) saturation temperature at given
pressure
(d) room temperature
(e) 20°C.
Ans: b
13. The specific volume of steam with
increase in pressure decreases
(a) linearly
(b) slowly first and then rapidly
(c) rapidly first and then slowly
(d) inversely
(e) none of the above.
Ans: c
14. The equivalent evaporation of a boiler is
a measure to compare
(a) the given boiler with the model
(b) the two different boilers of the same
make
(c) two different makes of boilers
operat¬ing under the same operating conditions
(d) two boilers of same make but operaing
under different conditions
(e) any type of boilers operating under any
conditions.
Ans: e
15. The coal requirement per kW hour
generation in the thermal power plant is of the order
of
(a) 0.1 to 0.2 kg
(b) 0.2 to 0.4 kg
(c) 0.6 to 0.8 kg
(d) 1.0 to 1.5 kg
(e) 1.5 to 2 kg.
Ans: c
16. Sublimation region is the region where
(a) solid and vapour phases are in equi-
librium
(b) solid and liquid phases are in
equilibrium
(c) liquid and vapour phases are in
equilibrium
(d) solid, liquid and vapour phases are in
equilibrium
(e) none of the above.
Ans: a
17. Stoichiometric quantity of air is the
(a) air present in atmosphere at NTP
conditions
(b) air required for complete combustion of
fuel with no excess air
(c) air required for optimum combustion so
as to have reasonable excess air
(d) air required to convert CO into C02
(e) air required to form an explosive
mixture.
Ans: b
18. One kg of steam sample contains 0.8 kg
dry steam; it's dryness fraction is
(a) 0.2
(b) 0.8
(c) 1.0
(d) 0.6
(e) 0.5.
Ans: b
19. If a steam sample is nearly in dry
condition, then its dryness fraction can be most
accurately determined by
(a) throttling calorimeter
(b) separating calorimeter
(c) combined separating and throttling
calorimeter
(d) bucket calorimeter
(e) none of the above.
Ans: a
20. If xx and x2 be the dryess fractions
obtained in separating calorimeter and throttling
calorimeter respectively, then the actual dryness
fraction of steam will be
(a) xxx2
(b) x, + x2
Ans: a
21. The specific heat of superheated steam
in kcal/kg is generally of the order of
(a) 0.1
(b) 0.3
(c) 0.5
(d) 0.8
(e) 1.0.
Ans: c
22. On Mollier chart, flow through turbine is
represented by '
(a) horizontal straight line
(b) vertical straight line
(c) straight inclined line
(d) curved line
(e) none of the above.
Ans: b
23. A wet vapour can be completely
specified by
(a) pressure only
(b) temperature only
(c) dryness fraction only
(d) specific volume only
(e) pressure and dryness fraction.
Ans: e
24. On Millier chart, the constant pressure
lines
(a) diverge from left to right
(b) diverge from right to left
(c) are equally spaced throughout
(d) first rise up and then fall
(e) none of the above.
Ans: a
25. On Mollier chart, free expansion, or
throttling process from high pressure to atmosphere
is represented by
(a) horizontal straight line
(b) vertical straight line
(c) straight inclined line
(d) curved line
(e) none of the above.
Ans: a
26. The bituminous coal is non-caking if its
carbon content is
(a) 78-81%
(b) 81-85%
(c) 85-90%
(d) 90-95%
(e) 95-100%.
Ans: a
27. The dry saturated steam at very low
pressure, (5-10 kg/cm2) when throttled to
atmosphere will become
(a) wet
(b) superheated
(c) remain dry satruated
(d) dry
(e) none of the above.
Ans: b
28. Water at pressure of 4 kg/cm2 and 160°C
temperature when exposed to atmosphere will
(a) boil
(b) flash i.e. get converted into steam
(c) remain as it was
(d) cool down
(e) none of the above.
Ans: b
29. The dry saturated steam at very high
pressure (150-200 kg/cm2) when throttled to
atmosphere will become
(a) wet
(b) superheated
(c) remain dry saturated
(d) dry
(e) none of the above.
Ans: a
30. In a throttling process
(a) steam temperature remaisn constant
(b) steam pressure remains constant
(c) steam enthalpy remains constant
(d) steam entropy remains constant
(e) steam volume remains constant.
Ans: c
31. In a throttling process
(a) heat transfer takes place
(b) work is done by the expanding steam
(c) internal energy of steam changes
(d) all of the above
(e) none of the above.
Ans: e
32. The pressure at which latent heat of
vaporisation of water is zero, is
(a) below atmospheric pressure
(b) 1 kg/cm2
(c) 100 kg/cm2
(d) 170 kg/cm2
(e) 225.6 kg/cm2.
Ans: e
33. Latent heat of dry steam at atmospneric
pressure is equal to
(a) 539 kcal/kg
(b) 539 BTU/lb
(c) 427 kcal/kg
(d) 100 kcal/kg
(e) 471 kcal/kg.
Ans: a
34. The latent heat of steam with increase
of pressure
(a) remains same
(b) increases
(c) decreases
(d) behaves unpredictably
(e) none of the above.
Ans: c
35. At critical point, i.e. p=225.65 kg/cm2,
the latent enthalpy of vaporisation is
(a) maximum
(b) minimum
(c) zero
(d) depends on temperature also
(e) none of the above.
Ans: c
36.  At which pressure the properties of water and
steam become identical
(a) 0.1 kg/cm2
(b) 1 kg/cm2
(c) 100 kg/cm2
(d) 225.6 kg/cm2
(e) it is never possible.
Ans: d
37. In an experiment to determine dryness
fraction of steam, the mass of water separated was
1.2 kg in 15 mts and the mass of steam passed out
in same time was 4.8 kg. Dryness fraction is
(a) 40%
(b) 25%
(c) 50%
(d) 80%
(e)90%.
Ans: d
38. While steam expands in turbines,
theoretically the entropy
(a) remains constant
(b) increases
(c) decreases
(d) behaves unpredictably
(e) none of the above.
Ans: a
39. Heating wet steam at constant
temperature is heating it at constant
(a) volume
(b) pressure
(c) entropy
(d) enthalpy
(e) none of the above.
Ans: b
40. Adiabatic process is
(a) essentially an isentropic process
(b) non-heat transfer process
(c) reversible process
(d) constant temperature process
(e) constant enthalpy process.
Ans: b
41. The state of vapour under saturation
condition is described by
(a) pressure alone
(b) temperature alone
(c) pressure and temperature
(d) pressure and dryness fraction
(e) dryness fraction alone.
Ans: d
42. Pick up the wrong statement about
critical condition of steam
(a) latent heat is zero
(b) liquid directly becomes steam
(c) specific volume of steam and liquid is
same
(d) this is the maximum pressure limit
(e) all properties of liquid and steam are
same.
Ans: d
43. Water boils when its vapour pressure
(a) equals that of the surroundings
(b) equals 760 mm of mercury
(c) equals to atmospheric pressure
(d) equals the pressure of water in the
container
(e) boiling has ^nothing to do with vapour
pressure.
Ans: a
45.  Mechanical equivalent of heat for 1 kcal or
Joule's equivalent is equal to
(a) 421 kgm
(b) 421 kgm
(c) 539 kgm
(d) 102 kgm
(e) 75 kgm.
Ans: a
46. Equivalent evaporation of water is the
evaporation "for a feed water supply at 100°C
(a) and its corresponding conversion into
dry saturated steam at 100°C and 1.033 kg/cm2
(b) and its corresponding conversion into
dry steam at desired boiler pressure
(c) conversion into steam at atmospheric
condition
(d) conversion into steam at the same
pres-sure at which feed water is supplied
(e) none of the above.
Ans: a
47. The evaporation of 15.653 kg of water
per hour from and at 100°C is called
(a) evaporative capacity
(b) factor of evaporation
(c) equivalent evaporation
(d) one boiler h.p.
(e) boiler efficiency.
Ans: d
48. The increase in pressure
(a) lowers the boiling point of a liquid
(b) raises the boiling point of a liquid
(c) .does not affect the boiling point of a
liquid
(d) reduces its volume
(e) none of the above.
Ans: b
49. During polytropic process
(a) heat transfer takes place across cylinder
walls
(b) work is done
(c) steam may be wet, dry or superheated
after expansion
(d) all of the above
(e) none of the above.
Ans: d
50. Hygrometery deals with the
(a) Hygroscopic substances
(b) water vapour in air
(c) temperature of air
(d) pressure of air
(e) density measurement.
Ans: b
51. Orsat meter is used for
(a) gravimetric analysis of the flue gases
(b) volumetric analysis of the flue gases
(c) mass flow of the flue gases
(d) measuring smoke density of flue gases
(e) none of the above.
Ans: b
52. Alkaline pyrogallate is used in Orsat's
apparatus for absorption of
(a) C02
(b) CO
(c) 02
(d) N2
(e) none of the above.
Ans: c
53. An ideal regenerative cycle is
(a) equal to carnot cycle
(b) less than carnot cycle
(c) more than carnot cycle
(d) could be anything
(e) none of the above.
Ans: b
54. Efficiency of rankine cycle can be
increased by
(a) decreasing initial steam pressure and
temperature
(b) increasing exhaust pressure
(c) decreasing exhaust pressure
(d) increasing the expansion ratio
(e) increasing number of regenerative
heaters.
Ans: a
55. Cochran boiler is a
(a) horizontal fire-tube boiler
(b) horizontal water-tube boiler
(c) veritcal water-tube boiler
(d) vertical fire tube boiler
(e) forced circulating boiler.
Ans: d
56. Lancashire 'boiler is a
(a) stationary fire tube boiler
(b) stationary water tube boiler
(c) water tube boiler with natural/forced
circulation
(d) mobile fire tube boiler
(e) none of the above.
Ans: a
57. Efficiency of a thermal cycle increases
by
(a) regeneration
(b) reheating of steam
(c) both (a) and (b)
(d) cooling of steam
(e) none of the above.
Ans: c
58. One kilowatt-hour energy is equivalent
to
(a) 1000 J
(b) 360 kJ
(c) 3600 kJ
(d) 3600 kW/sec
(e) 1000 kJ.
Ans: c
59. Which of the following gases has the
highest calorific value
(a) producer gas
(b) coal gas.
(c) water gas
(d) blast furnace gas
(e) coke oven gas.
Ans: b
60. 100% efficiency of a thermal cycle cannot be
achieved because of
(a) frictional losses
(b) it is not possible to achieve 0°K
temperature
(c) leakage
(d) non-availability of ideal substance
(e) none of the above.
Ans: b
61. For burning 1 kg of carbon to CO as per
chemically correct combusiton, amount of air
required is
(a) 1 kg
(b) 4/3kg
(c) 8/3kg
(d) 2 kg
(e) 16/3 kg.
Ans: b
62. The diameter of Cornish boiler is of the
order of
(a) 1-2 m
(b) 1.5-2.5 m
(c) 2-3 m
(d) 2.5-3.5 m
(e) 0.5 to 1 m.
Ans: a
63. The lenght of Cornish boiler is of the
order of
(a) 2-4 m
(b) 3-5 m
(c) 5-7.5 m
(d) 7-9 m
(e) 9-11 m.
Ans: c
64. The diameter of fire tube of Cornish
boiler compared to its shell is
(a) one half
(b) one third
(c) one-fifth
(d) two-fifth
(e) three-fifth.
Ans: a
65. Steam engine operates on
(a) carnot cycle
(b) joule cycle
(c) Stirling cycle
(d) brayton cycle
(e) none of the above.
Ans: d
66. The change in internal energy in steam
engines equals to
(a) work done during the rankine cycle ;
(b) work done during compression.
(c) work done during adiabatic expansion
(d) change in enthalpy
(e) none of the above.
Ans: a
67. Water tube boilers are those in which
(a) flue gases pass through tubes and
water around it
(b) water passes through the tubes and
flue gases around it
(c) work is done during adiabatic
expansion
(d) change in enthalpy
(e) none of the above.
Ans: c
68. Locomotive type' boiler is
(a) horizontal multitubular water tube boiler
(b) water wall enclosed furnace type
(c) vertical tubular fire tube type
(d) horizontal multi-tubular fire tube type
(e) none of the above types.
Ans: d
69. Lancashire boiler is of
(a) stationary<fire tube-type
(b) horizontal type
(c) natural cirulation type
(d) internally fired type
(e) all of the above.
Ans: e
70. Fire tube boilers are those in which
(a) flue gases pass through tubes and water
around it
(b) water passes through the tubes and flue
gases around it
(c) forced circulation takes place
(d) tubes are laid vertically
(e) none of the above.
Ans: a
71. Which of the following substance will
have same percentage in both proximate and
ultimate analysis
(a) ash
(b) volatile matter
(c) moisture
(d) hydrogen
(e) none of the above.
Ans: a
72. The number of flue tubes in Lancashire
boiler is
(a) zero
(b) one
(c) two
(d) four
(e) many.
Ans: c
73. Which of the following is a fire tube
boiler
(a) locomotive boiler
(b) Babcock and Wilcox boiler
(c) Stirling boiler.
(d) all of the above
(e) none of the above.
Ans: a
74. Which of the following is a water tube
boiler
(a) locomotive boiler
(b) Cochran boiler
(c) Cornish boiler
(d) Babcock and Wilcox boiler
(e) Lancashire boiler.
Ans: d
75. The diameter of cylindrical shell of the
Lancashire boiler is of the order of
(a) 1 tp 1.25m
(b) 1 to 1.75 m
(c) 2 to 4 m
(d) 1.75 to 2.75 m
(e) 2.25 to 4.5 m.
Ans: d
76. A packaged boiler is one in which
various parts like firing equipment, fans, feed
pumps and automatic controls are
(a) supplied by same manufacturer loose
and assembled at site
(b) supplied mounted on a single base
(c) purchased from several parties and
packed together at site
(d) packaged boiler does not exist
(e) none of the above.
Ans: b
77. The biggest size of thermal power unit
operating in India is
(a) 30 MW
(b) 60 MW
(c) 100 MW
(d) 210 MW
(e) 500 MW.
Ans: e
78. Which of the following coals has the
highest calorific value
(a) anthracite coal
(b) bituminous coal
(c) lignite
(d) peat
(e) wood.
Ans: a
79. The high pressure boiler is oiie
producing steam at a pressure more than
(a) atmospheric pressure
(b) 5 kg/cm2
(c) 10 kg/cm2
(d) 40 kg/cm2
(e) 75-80 kg/cm2.
Ans: e
80. The crown of the fire box is made
hemispherical in order to
(a) give maximum space
(b) give maximum strength
(c) withstand pressure inside boiler ,
(d) resist intense heat in fire box
(e) enable easy,manufacture.
Ans: d
81. Which of the following is steam dbal
(a) non-coking bituminous coal
(b) brown coal
(c) pulverised coal
(d) coking bituminous coal
(e) none of the above.
Ans: a
82. The fire tubes in, a Coarran and Scotish
marine boiler are
(a) horizontal
(b) vertical
(c) inclined
(d) both horizontal and vertical
(e) horizontal and inclined.
Ans: a
83. The diameter of internal flue tubes in a
Lancashire boiler compared to its shell is
(a) one-half
(b) one-third
(c) one-fourth
(d) one-fifth
(e) two-fifth.
Ans: e
84. The basic purpose of drum in boiler is
to
(a) serve as storage of steam
(b) serve as storage of feed water for water
wall
(c) remove salts from water
(d) separate steam from water
(e) control level.
Ans: d
85. Duplex feed pumps are used in small
steam boilers. These operate on the principle of
(a) centrifugal pump
(b) axial flow pump
(c) gear pump
(d) ejector pump
(e) reciprocating pump.
Ans: e
86. The best suited coal for chain or
travelling grate stoker boiler is
(a) coking coal
(b) non coking or free burning coal
(c) pulverised coal
(d) high sulphur coal
(e) least ash content coal.
Ans: b
87. In natural circulation type boiler,
(a) heating takes place at bottom and the
water supplied at bottom gets converted into the
mixture of steam bubbles and hot water which rise
to drum
(b) water is supplied in durm and through
down-comers located in atmospheric conditon it
passes to the water wall and rises to drum in the
form of mixture of water and steam
(c) feed pump is employed to supplement
natural circulation in water wall type furnace
(d) water is converted into steam in one .
pass without any recirculation
(e) water is fed at atmospheric pressure.
Ans: a
88. Hard coke is produced by carborisation
of coal at
(a) atmospheric temperature
(b) 500-600°C
(c) 70O-850°C
(d) 95O-1100°C
(e) 120O-1500°C.
Ans: d
89.. Hard coke is used in
(a) cement industry
(b) thermal power plant
(c) blast furnace
(d) domestic use
(e) locomotives
Ans: c
90. Pick up the correct statement as
regards Cornish boiler and Lancashire boiler
(a) cornish is fire tube and lancashire is
water tube
(b) cornish is water tube and lancashire is
fire tube
(c) cornish has two fire tubes and
lancashire has one
(d) lancashire has two fire tubes and
cornish has one
(e) both have two fire tubes.
Ans: d
91. In locomotive boiler, maximum steam
pressure is limited to
(a) 1 kg/cm2
(b) 5 kg/cm2
(c) 10 kg/cm2
(d) 18 kg/cm2
(e) 31 kg/cm2.
Ans: d
92. Locomotive boiler is of the following
type
(a) multitubular
(b) horizontal
(c) internally fired
(d) mobile
(e) all of the above.
Ans: e
93. The shell diameter and length of
locomotive boiler are
(a) 1.5 m, 4 m
(b) 1.5 m, 6 m
(c) 1 m, 4 m
(d) 2 m, 4 m
(e) 1.5 m, 8 m.
Ans: a
94. The diameters of fire tubes and
superheaer tubes in locomotive boiler are
(a) 47.5 mm, 130 mm
(b) 32.5 mm, 180 mm
(c) 65.5 mm, 210 mm
(d) 24.5 mm, 65 mm
Ans: a
95. The water tubes in a babcock and
wilcox boiler are
(a) horizontal
(b) vertical
(c) inclined
(d) horizontal and inclined
(e) vertical and inclined.
Ans: c
96. Which of the following varieties of coals
is mostly used in steam boilers
(a) non-coking bituminous coal
(b) brown coal
(c) peat
(d) coking bituminous coal
(e) none of the above.
Ans: e
97. The diameter of tubes for natural
circulation boiler as compared to controlled
circulation boilers is
(a) more
(b) less
(c) same
(d) could be more or less depending on
other factors
(e) none of the above.
Ans: a
98. A boiler in India should conform to
safety regulations of
(a) DIN
(b) BS
(c) ASTM
(d) IBR
(e) GOST.
Ans: d
99. The  function  of injector used in small
steam plants is to
(a) create vacuum in furnace
(b) create vacuum at turbine exhaust
(c) pump feed water
(d) dose chemicals in feed water
(e) control steam temperature by injecting
water.
Ans: c
100. Which of the following boilers is best
suited to meet fluctuating demands
(a) babcock and wilcox
(b) locomotive
(c) lancashire
(d) cochran
(e) comish.
Ans: b
101. The difference between cornish boiler
and lancashire boiler is that
(a) former is fire tube type and latter is
water tube type boiler
(b) former is water tube type and latter is
fire tube type
(c) former contains one fire tube and latter
contains two fire tubes
(e) none/of the above.
Ans: c
102. In accelerated circulation type boiler
(a) heating takes place at bottom and the
water supplied at bottom gets converted into the
mixture of stdam bubbles and hot water which rise
to durm
(b) water is supplied in drum and through
downcomers" located in atmospheric conditon it
passes to the water wall and rises to durm in the
from of mixture of water and steam
(c) feed pump is employed to supplement
natural circulation in water wall type furnace
(e) water is converted into steam in one pass
without any recirculation
(e) water is fed under high pressure and high
velocity.
Ans: b
103. Pick up the wrong statement about
water tube boiler in comparison to fire tube boilers
(a) former generates steam at high
pressure
(b) former occupies less space for same
power
(c) rate of steam flow is more in former
case
(d) former is used for high installed
capacity
(e) chances of explosion are less in former
case.
Ans: e
104. The number of drums in Benson steam
generator is
(a) one
(b) two
(c) one steam drum and one water drum
(d) no drum
(e) none of the above.
Ans: d
105. A fusible plug is fitted in small boilers in
order to
(a) avoid excessive build up of pressure
(b) avoid explosion
(c) extinguish fire if water level in the boiler
falls below alarming limit
(d) control steam dome
(e) remove molten aslj.
Ans: c
106. The fusible plug in small boilers is
located
(a) in the drum
(b) in the fire tubes
(c) above steam dome
(d) over the combustion chamber
(e) at the inlet of chimney.
Ans: d
107.  Fusible plug for boilers is made of fusible
metal containing tin, lead, and
(a) bismuth
(b) copper
(c) aluminium
(d) nickel
(e) iron.
Ans: a
108. Boiler H.P. is defined as the
(a) steam evaporation rate per kg of fuel
fired
(b) work done in evaporating 1 kg of steam
per hour from and at 100°C into dry saturated
steam
(c) the evaporation of 15.65 kg of water per
hour from and at 100°C into dry saturated steam
(d) work done by 1 kg of steam at
saturation condition
(e) heat consumed in evaporating 1 kg water at
0°C to steam at 100°C and 1.033 kg/cm pressure.
Ans: c
109. In forced recirculation type boiler,
(a) heating takes place at bottom and the
water supplied at bottom gets converted into the
mixture of steam bubbles and hot water which rise
to drum
(b) water is supplied in drum and through
down-comers located in atmospheric condition it
passes to the water wall and rises to drum in the
form of mixture of water and steam
(c) feed pump is employed to supplement
natural circulation in water wall type furnace
(d) water is converted into steam in one
pass without any recirculation
(e) heating of water takes place in stages.
Ans: c
110. The ratio of heat utilised to produce
steam and the heat liberated in furnace is known as
(a) boiler effectiveness
(b) boiler evaporative capacity
(c) factor of evaporation
(d) equivalent evaporation
(e) boiler efficiency.
Ans: e
111. Steam in water tube boiler as compared
to fire tube boiler
(a) can be raised rapidly
(b) is raisd at slower rate
(c) is raised at same rate
(d) could be raised at fast/slow rate
depending on design
(e) none of the above is true.
Ans: a
112. Thermal efficiency of well maintained
boiler will be of the order
(a) 20%
(b) 40%
(c) 50%
(d) 75%
(e) 90%.
Ans: e
113. Thermal efficiency of a thermal power
plant is of the order of
(a) 15%
(b) 20%
(c) 30%
(d) 45%
(e ) 60%.
Ans: c
114. It is required to produce large amount
of steam at low pressure. Which boiler should be
used ?
(a) pulverised fuel fired boiler
(b) cochran boiler
(c) lancashire boiler
(d) babcock and wilcox boiler
(e) stoker fired boiler.
Ans: c
115. The overall efficiency of thermal power
plant is
(a) boiler efficiency, turhine efficiecny,
generator efficiency
(b) all the three above plus gas cycle
efficiency
(c) carnot cycle efficiency
(d) regenerative cycle efficiency
(e) rankine cycle efficiency.
Ans: a
116. Which type of boiler can meet rapid
changes of load
(a) vertical fire tube type
(b) horizontal fire tube type
(c) horizontal water tube type
(d) vertical water tube type
(e) forced circulation type.
Ans: e
117. In forced circulation type boiler
(a) heating takes place at bottom and the
water supplied at bottom gets converted into the
mixture of steam bubbles and hot water which rise
to drum
(b) water is supplied in drum and through
down-comers located in atmospheric condition it
passes to the water wall and rises to drum in the
form of mixture of water and steam
(c) feed pump is employed to supplement
natural circulation in water wall type furnace
(d) water is converted into steam in one
pass without any recirculation
(e) water is heated in a large number of
tubes.
Ans: d
118. Boiler stays are used to
(a) prevent flat surfaces under pressure
from tearing apart
(b) take care of failure in shear
(c) take care of failure in compression
(d) provide support for boiler
(e) provide foundation of boiler.
Ans: a
119. The radius of a dished head is taken
approximately as
(a) one-fourth
(b) half
(c) one
(d) two
(e) three.
Ans: c
120. Size of boiler tubes is specified by
(a) mean diameter and thickness
(b) inside diameter and thickness
(c) outside diameter and thickness
(d) outside diameter and inside diameter
(e) outside diameter alone.
Ans: c
121. The heat loss in a boiler takes place in
the form of
(a) heat carried away by flue gases
(b) heat carried away by ash
(c) moisture present in fuel and steam
formed by combustion of hydrogen in fuel
(d) radiation
(e) all of the above.
Ans: e
122. The major axis of elliptical manholes on
the shell should be provided
(a) longitudinally
(b) circumferentially
(c) on dished end
(d) anywhere
(e) vertically.
Ans: b
123. In which of the following boilers, the
draught in furnace is increased by utilising exhaust
steam from engine
(a) lancashire boiler
(b) locomotive boiler
(c) babcock and wilcox boiler
(d) cochran boiler
(e) benson boiler.
Ans: b
124. With increase in load, radiant
superheater has
(a) drooping characteristic
(b) lihear characterisstic
(c) rising characteristic
(d) flat characteristic
(e) none of the above.
Ans: a
125. With increase in load, convection
superheater has
(a) drooping characteristic
(b) linear characterisstic
(c) rising characteristic
(d) flat characteristic
(c) none of the above.
Ans: c
126. The diameter of fire tubes in Cochran
boiler is of the order of
(a) 2 cm
(b) 6 Cm ,
(C) 8 cm
(d) 12 cm
(e) 15 cm.
Ans: b
127. In a recuperative air preheater, the heat
is transferred
(a) from a metal wall from one medium to
another
(b) from heating an itermediate material
and then heating the air from this material
(c) by direct mixing ,
(d) heat is transferred by bleeding some
gases from furnace
(e) none of the above.
Ans: a
128. A safety valve in a locomotive starts
leaking. The leaking medium will be
(a) water
(b) dry steam
(c) wet steam
(d) super heated steam
(e) supersaturated steam.
Ans: d
129. The temperature of flue gases at air
heater outlet should be
(a) 100°C
(b) above dew-point temperature of flue
gases
(c) below dew-point temperature of flue
gases
(d) less than wet bulb temperature of flue
gases
(e) above wet bulb temperature of flue
gases.
Ans: b
130. In regenerative air preheater, the heat
is transferred
(a) from a metal wall from one medium to
another
(b) from heating an intermediateanaterial
and then heating the air from this material
(c) by direct mixing
(d) heat is transferred by bleeding some
gas from furnace
(e) none of the above.
Ans: b
131. In designing air preheater, the important
design consideration is that
(a) approach temperature should be as
low as possible
(b) handling and maintenance should be
easier
(c) heat transfer area should be optimum
(d) stack gases should not be cooled to the
dew point
(e) none of the above.
Ans: d
132. The pressure of reheat steam after
passing through reheater compared to inlet
condition is
(a) more
(b) less
(c) equal
(d) may be more or less depending on
capacity of reheater
(e) none of the above.
Ans: b
133. The function of injector used in small
capacity boilers is to
(a) create vacuum
(b) inject chemical solution in feed pump
(c) pump water, similar to boiler feed
pump
(d) add make up water in the system
(e) none of the above.
Ans: c
134. The safety valve at superheater as
compared to drum safety valve setting is set at
(a) higher value
(b) lower value
(c) same value
(d) any value
(e) none of the above.
Ans: b
135. The height of chimney in a power plant
is governed by
(a) the draft to be created
(b) limitation of construction facilities
(c) control of pollution
(d) quantity of flue gases to be handled
(e) all of the above.
Ans: c
136. Steam exhaust from high pressure
turbine is reheated in
(a) boiler drum
(b) superheater tubes
(c) economiser
(d) a separate coil
(e) a separate coil located in convection path.
Ans: e
137. Vacuum for reciprocating steam
engines compared to steam turbines is
(a) more
(b) equal
(c) less
(d) could be more or less depending on the
size of plant
(e) none of the above.
Ans: c
138. Expanding steam to a very low
prseeure (high vacuum) in steam engines is
(a) desirable
(b) economical
(c) essential
(d) optional
(e) uneconomical.
Ans: e
139. In locomotives, the draught is produced
by
(a) chimney
(b) induced draft fan
(c) both combined (a) and (b)
(d) steam jet draught
(e) none of the above.
Ans: d
140. Reheating of steam under ideal
conditions takes place at constant
(a) entropy
(b) enthaply
(c) pressure
(d) temperature
(e) all of the above.
Ans: d
141. The maximum discharge through a
chimney occurs when the height of chimney is
(a) infinitely long
(b) around 200 meters
(c) equal to the height of the hot gas
column producing draught
(d) outside temperature is very low
(e) more than the tallest building nearby.
Ans: c
142. Proximate analysis of fuel is
determination of percentage of
(a) carbon, hydrogen, nitrogen, sulphur,
moisture
(b) fixed carbon, ash, volatile matter,
moisture
(c) higher calorific value
(d) lower calorific value
(e) rough analysis.
Ans: b
143. Which device is used in thermal power
plants to reduce level of pollution
(a) induced draft fan
(b) smoke meter
(c) chimney
(d) precipitator
(e) pulveriser.
Ans: d
144. Bomb calorimeter is used to determine
(a) Higher calorific value at constant
volume
(b) Lower calorific value at constant
volume ,
(c) Higher calorific value at constant
pressure
(d) Lower calorific value at constant
pressure
(e) None of the above.
Ans: a
145. Ultimate analysis of fuel is determination of
percentage of
(a) carbon, hydrogen, nitrogen, sulphur,
moisture
(b) fixed carbon, ash, volatile matter,
moisture
(c) higher calorific value
(b) lower calorific value
(e) best analysis.
Ans: a
146. For combutsion of a fuel, following is
essential
(a) correct fuel air ratio
(b) proper ignition temperature
(c) 02 to support combustion
(d) all the three above
(e) none of the above.
Ans: d
147. Spontaneous combustion is a
phenomenon in which
(a) all the fuel burns instantaneously
producing high energy release
(b) fuel burns with less air
(c) coal bursts into flame without any
external ignition source but by itself due to gradual
increase in temperature as a result of heat released
by combination of oxygen with coal
(d) explosion in furnace
(e) none of the above.
Ans: c
148. The economiser is used in boilers to
(a) increase thermal efficiency of boiler
(b) economise on fuel
(c) extract heat from the exhaust flue
gases
(d) increase flue gas temperature
(e) to heat feed water by bled steam.
Ans: a
149. An economiser in a boiler
(a) increases steam pressure
(b) increases steam flow
(c) decreases fuel consumption
(d) decreases steam pressure
(e) increases life of boiler.
Ans: c
150. 02 content in atmospheric air on
volume basis is
(a) 21%
(b) 23%
(d) 30%
(d) 40%
(e) 70%.
Ans: a
151. 02 content in atmospheric air on weight
basis is
(a) 21%
(b) 23%
(c) 30%
(d) 40%
(e ) 70%.
Ans: b
152. Primary air is the air used to
(a) provide air around burners for obtaining
optimum combustion
(b) transport and dry the coal
(c) convert CO (formed in lower zone of
furnace) into C02 at higher zone
(d) air-delivered by forced draft fan
(e) none ot the above.
Ans: b
153. Sulphur content of fuels is very
important to the plant operators because it
(a) has high heating value
(b) retards electric precipitation
(c) promotes complete combustion
(d) has highly corrosive effect
(e) facilitates ash removal.
Ans: d
154. Presence of moisture in fuel oil would
(a) keep the burner tips cool
(b) aid in proper combustion
(c) cause sputtering, possibly
extinguish¬ing flame
(d) clean the nozzles
(e) reduce flame length.
Ans: c
155. Gusset stays in a boiler are provided to
(a) prevent the bulging of flat surfaces
(b) avoid explosion in furnace
(c) prevent leakage of hot flue gases
(d) support furnace freely from top
(e) prevent atmospheric air leaking into
furnace.
Ans: a
156. Water and sediment in fuel oil can be
removed by
(a) heating the oil in the settling tanks
(b) cooling the oil in the settling tanks
(c) burning the oil
(d) suspension
(e) filtering.
Ans: a
157. Pour point of fuel oil is the
(a) lowest temperature at which oil will flow
under set condition
(b) storage temperature
(c) temperature at which fuel is pumped
through burners
(d) temperature at which oil is transported
(e) none of the above.
Ans: a
158. Secondary air is the used to
(a) provide air around burners for obtaining
optimum combustion
(b) transport and dry the coal
(c) convert CO (formed in lower zone of
furnace) into C02 at higher zone
(d) air delivered by induced draft fan
(e) air fed to pulverisers.
Ans: a
159. The behaviour of coal in a furnace is
determained by
(a) the content of sulphur
(b) the content of ash and heating value
(c) the proximate analysis
(d) the exact analysis
(e) its type.
Ans: c
160. Pick up wrong statement about desired
properties of a good fuel
(a) high calorific value
(b) produce minimum smoke and gases
(c) ease in storing
(d) high ignition point
(e) ecomomical
Ans: d
161. Sulphur in coal results in
(a) causing clinkering and slagging
(b) corroding air heaters
(c) spontaneous combustion during coal
storage
(d) facilitating ash precipitation
(e) all of the above.
Ans: e
162. Caking coals are those which
(a) form lumps or masses of coke
(b) burn freely
(c) show little or no fusing action
(d) burn completely
(e) do not form ash.
Ans: a
163. Green coal, in order to be burnt, must
be
(a) heated sufficiently
(b) burnt in excess air
(c) heated to its ignition point
(d) burnt as powder
(e) burnt as lumps.
Ans: c
164. The ultimate analysis of fuel lists
(a) various chemical constituents, carbon,
hydrogen, oxygen etc, plus ash as per-cents by
volume
(b) various chemical constituents, carbon,
hydrogen, oxygen, etc, plus ash as per-cents by
weight
(c) fuel constituents as percents by volume
of moisture, volatile, fixed carbon and ash
(d) fuel constituents as percents by weight
of moisture, volatile, fixed carbon and ash
(e) moisture and ash free heating value.
Ans: b
165. The proximate analysis of fuel lists
(a) various chemical constituents, carbon,
hydrogen, oxygen etc, plus ash as per-cents by
volume
(b) various chemical constituents, carbon,
hydrogen, oxygen, etc, plus ash as per-cents by
weight
(c) fuel constituents as percents by volume
of moisture, volatile, fixed carbon and ash
(d) fuel constituents as percents by weight
of moisture, volatile, fixed carbon and ash
(e) moisture and ash free heating value.
Ans: d
166. Tertiary air is the air used to
(a) provide air around burners for obtaining
optimum combustion
(b) transport and dry the coal
(c) cool the scanners
(d) supply air for ignitors
(e) convert CO (formed in lower zone of
furnace) into C02 at higher zone.
Ans: e
167. The safety valve on boiler drum
compared to safety valve on superheater is set at
(a) same value
(b) higher value
(c) lower value
(d) lower/higher depending on steam flow
(e) unpredicatble.
Ans: b
168. Which is not correct statement about
pulverised fuel firing
(a) high burning rate is possible
(b) heat release can be easily controlled
(c) fuel burns economically
(d) it is the best technique for burning high
ash content fuel having low fusion ash
(e) separate mills are required to powder
the coal.
Ans: d
169. The three "Ts" for good combustion are
(a) temperature, time, and turbulance
(b) total air, true fuel, and turbulance
(c) thorough mixing, total air, and
temperature
(d) total air, time, and temperature
(e) none of the above.
Ans: a
170.  Which is not correct statement about the
function of furnace
(a) to provide proper conditions for con-
tinuous complete combustion
(b) mix fuel with air and ignite
(c) separate ash from coal
(d) maintain heat supply to prepare and
ignite the incoming fuel
(e) to minimise radiation losses.
Ans: c
171. Which is not correct statement about effect of
sulphur in fuel
(a) it has heating value
(b) it helps in electrostatic precipitation of
ash in flue-gases
(c) it leads to corrosion of air heaters,
ducting, etc. if flue gas exit temperature is low
(d) it erodes furnace walls
(e) none of the above.
Ans: d
172. Heating value of fuel used is as on fired basis.
If it is reported for dry or moisture free fuel, then
latter should be multiplied by the following factor to
correct for as fired value
(a) (1- moisture content)
(b) (1 + moisture content)
(c) 1 + moisture content
(d) 1 - moisture content
Ans: a
173. Gardually increasing temperature of flue
gases at inlet to chimney for given steam outputs is
an indication of
(a) higher effectiveness of boiler
(b) high calorific value coal being burnt
(c) fouling of heat transfer surfaces
(d) raising of steam temperature
(e) leakage of air.
Ans: c
174. Incomplete combustion can be best
judged by
(a) smoky chimney exit
(b) excess air in flue gases
(c) measuring carbon mono-oxide in flue
gases
(d) measuring temperature of flue gases at
exit of furnace
(e) measuring oxygen in flue gases.
Ans: c
175. The capacity of induced draft fan
compared to forced draft fan in a boiler is
(a) same
(b) more
(c) less
(d) less or more depending on size of boiler
(e) unpredictable.
Ans: b
176.

Nuclear Power Plants - Mechanical Engineering Multiple Choice Questions and Answers

Nuclear Power Plants -
Multiple Choice Questions and Answers

1. The efficiency of a nuclear power plant in
comparsion to a conventional thermal power plant is
(a) same
(b) more
(c) less
(d) may be less or mote depending on size
(e) unpredictable.
Ans: c
2. Isotopes of same elements have
(a) same atomic number and different masses
(b) same chemical properties but different atomic
numbers
(c) different masses and different atomic numbers
(d) different chemical properties and same atomic
numbers
(e) same chemical properties and same atomic
numbers.
Ans: b
3. Atomic number of an element in the periodic table
represents the numbers of
(a) protons in the nucleus
(b) electrons in me nucleus
(c) neutrons in the nucleus
(d) electrons in the atom
(e) neutrons in the atom.
Ans: a
4. The mass number of a substance represents the
sum of total number of
(a) protons and neutrons in an atom
(b) protons and electrons in an atom
(c) neutrons and electrons in an atom
(d) protons and neutrons in a nucleus
(e) protons and electrons in a nucleus.
Ans: d
5. Which is not identical for an atom and an isotope
(a) mass number
(b) atomic number
(c) chemical properties
(d) position in periodic table
(e) all of the above.
Ans: a
6. Amongst the following, the fissionable materials
are
(a) U233andPu239
(b) U23iandPu233
(c) U235andPu235
(d) U238andPu239
(e) U243andPu235
Ans: a
6. A nuclear unit becoming critical means
(a) it is generating power to rated capacity
(b) it is capable of generating much more than rated
capacity
(c) there is danger of nuclear spread
(d) chain reaction that causes automatic splitting
of the fuel nuclei has been established
(e) it generates no heat.
Ans: d
7. Moderator in nuclear plants is used to
(a) reduce temperature
(b) extract heat from nuclear reaction
(c) control the reaction
(d) cause collision with the fast moving neutrons to
reduce their speed
(e) moderate the radioactive pollution.
Ans: d
8. The most commonly used moderator in nuclear
plants is
(a) heavy water
(b) concrete and bricks
(c) graphite and concrete
(d) deutrium
(e) graphite.
Ans: e
9. The nuclear energy is measured as
(a) MeV
(b) curie
(c) farads
(d) MW
(e) kWhr.
Ans: a
10. The total energy released in fission of U is
(a) 5 MeV
(b) 10 MeV
(c) 199 MeV
(d) 168 MeV
(e) 11 MeV.
Ans: c
11. Breeder reactor has a conversion ratio of
(a) unity
(b) more than unity
(c) less than unity
(d) zero
(e) infinity.
Ans: b
12. Boiling water reactor employs
(a) boiler
(b) direct cycle of coolant system
(c) double circuit system of coolant cycle
(d) multi pass system
(e) single circuit system.
Ans: b
13. Fast breeder reactor uses
(a) boiler
(b) direct cycle of coolant system
(c) double circuit system of coolant cycle
(d) multi pass system
(e) single circuit system.
Ans: c
14. One gram of uranium will produce energy
equivalent to approximately
(a) 1 tonne of high grade coal
(b) 4.5 tonnes of high grade coal
(c) 10 tonnes of high grade coal
(d) 100 tonnes of high grade coal
(e) 1000 tonnes of high grade coal.
Ans: b
15.  Which of the following nuclear reactor does not
need a heat exchanger for generation of steam
(a) gas cooled
(b) liquid metal cooled
(c) pressurised water
(d) boiling water
(e) none of the above.
Ans: d
16.  The number of isotopes of hydrogen are
(a) 1
(b) 2
(c) U
(c) 3
(e) 0
Ans: c
17. The commonly used material for shielding is
(a) lead or concrete
(b) lead and tin
(c) graphite or cadmium
(d) thick galvanised sheets
(e) black carbon papers.
Ans: a
18. The main interest of shielding in nuclear reactor
is protection against
(a) X-rays
(b) infra-red rays
(c) a, P, and y rays
(d) neutrons and gamma rays
(e) electrons.
Ans: d
19. Reflector in nuclear plants is used to
(a) return the neutrons back into the core
(b) shield the radioactivity completely
(c) check polllution
(d) conserve energy
(e) is not used.
Ans: a
20. The energy required to be applied to a
radioactive nucleus for the emission of a neutron is
(a) 1 MeV
(b) 2.4 MeV
(c) 4.3 MeV
(d) 7.8 MeV
(e) 20 MeV.
Ans: d
21. Which of the following are ferrite materials
(a) U233andPu239
(b) U
(c) U238andPu239
(d) U238andTh239
(e) none of the above
Ans: b
22. Ferrite material is
(a) the most fissionable material
(b) the basic fuel for nuclear paints
(c) basic raw material for nuclear plants
(d) the material which absorbs neutrons and
undergoes spontaneous changes leading to the
formation of fissionable material
(e) none of the above.
Ans: d
23. Enriched uranium is one in which
(a) %age of U235 has been artificially in-creased
(b) %age of U has been artificially increased
(c) %age of U234 has been artificially in-creased
(d) extra energy is pumped from outside
(e) all impurities have been removed.
Ans: a
24.  Which of the following particles is the lightest
(a) nucleus
(b) electron
(c) proton
(d) meson
(e) neutron.
Ans: b
25. Which of the following is the heaviest
(a) neutron
(b) proton
(c) atom
(d) electron
(e) nucleus.
Ans: c
26.  In fast breeder reactors
(a) any type of moderator can be used
(b) graphite is used as the moderator
(c) heavy water is used as the moderator
(d) moderator may or may not be used
(e) moderator is dispensed with.
Ans: e
27. In nuclear fission each neutron that causes
fission releases
(a) no new neutron
(b) at least one new neutron
(c) one new neutron
(d) more than one new neutrons
(e) many-fold neutrons.
Ans: d
28. The breeding gain in case of thermal breeder
reactor as compared to fast breeder reactor is
(a) same
(b) lower
(c) higher
(d) unity
(e) higher/lower depending on the size of reactor.
Ans: b
29. Gas cooled reactor uses following materials as
moderator, and coolant
(a) graphite, C02
(b) graphite, air
(c) heavy water, C02
(d) lead, H2
(e) concrete, N2.
Ans: a
30. A nuclear fission produces energy of following
order in MeV
(a) 20
(b) 200
(c) 2000
(d) 20,000
(e) 2 x 105.
Ans: b
31. The process by which a heavy nucleus is
splitted into two light nuclei is known as
(a) splitting
(b) fission
(c) fusion
(d) disintegration
(e) chain reaction.
Ans: b
32. A nuclear fission is initiated when the critical
energy as compared to neutron binding energy of
the atoms is
(a) same
(b) more
(c) less
(d) there is no such criterion
(e) none of the above.
Ans: b
33. The fast breeder reactor uses the following
moderator
(a) demineralised water
(b) carbon dioxide
(c) heavy water
(d) graphite
(e) no moderator is used.
Ans: e
34. The first unclear power plant in India is located
at
(a) Kota
(b) Kalapakkam
(c) Tarapur
(d) Baraeilly
(e) Kerala.
Ans: c
35. The nuclear power plant at Tarapur has the
following reactor
(a) fast breeder
(b) pressurised water
(c) boiling water
(d) sodium graphite
(e) none of the above.
Ans: c
35. Boiling water reactor uses the following as
moderator, coolant and working fluid
(a) ordinary fluid
(b) heavy water
(c) molten lead
(d) hydrogen gas
(e) none of the above.
Ans: a
36. Ideally the neutron flux in reactor should be
(a) maximum in center and zero at side
(b) maximum at side and zero in center
(c) uniform throughout
(d) zero throughout
(e) none of the above.
Ans: c
37. Enriched uranium may contain fissionable
contents of the order of
(a) 1-99%
(b) 1-25%
(c) 1-50%
(d) 1-75%
(e) 1-90%.
Ans: a
38. U235 will undergo fission by
(a) high energy (fast) neutrons alone
(b) low energy (slow) neutrons alone
(c) either fast or slow neutrons
(d) medium energy neutrons
(e) none of the above.
Ans: c
39. U238 will undergo fission by
(a) high energy (fast) neutrons alone
(b) low energy (slow) neutrons alone
(c) either fast or slow neutrons
(d) medium energy neutrons
(e) none of the above.
Ans: a
40. A reactor capable of converting a ferrite material
into fissile isotopes is called
(a) regenerative reactor
(b) fast breeder reactor
(c) breeder reactor
(d) boiling water reactor
(e) ferrite reactor.
Ans: a
41. Hydrogen is preferred as better coolant in
comparison to C02 because former
(a) is lighter
(b) is inert
(c) has high specific heat
(d) is a good conductor
(e) all of the above.
Ans: c
42. Natural uranium is made up of
(a) 99.282% U238, 0.712% U235, 0.006% U234
(b) 99.282% U235, 0.712% U238,  0.06%' U234
(c) 99.282% U234, 0.712% U238, 0.006% U235
(d) 99.282% U235, 0.712% U234, 0.006% U238
(e) none of the above.
Ans: a
43. The risk of radioactive hazard is greatest in the
turbine with following reactor
(a) pressurised water
(b) boiling water
(c) gas cooled
(d) liquid metal cooled
(e) all of the above.
Ans: b
44. Plutonium is produced
(a) as basic raw material
(b) by neutron irradiation of Uz
(c) by neutron irradiation of throium
(d) artificially
(e) in high capacity furnace.
Ans: b
45. Electron-volt is the unit of
(a) atomic power
(b) energy
(c) voltage
(d) radio activity
(e) there is no such unit.
Ans: b
46. Pick up the wrong statement
(a) In a heterogeneous or solid-fuel reactor, the fuel
is mixed in a regular pattern within moderator.
(b) Slow or thermal neutrons have energy of the
order or 0.025 eV
(c) Fast neutrons have energies above 1000 eV
(d) Fast reactor uses moderator
(e) Most serious drawback in using water as
coolant in nuclear plants is its high vapour
pressure.
Ans: d
47. The unit of radio-activity is
(a) electron-volt
(b) electron-ampere
(c) curie
(d) MeV
(e) AMU.
Ans: c
48. Pick up the wrong statement Fast breeder
reactors
(a) operate at extremely high power densities.
(b) are liquid-metal cooled
(c) produce more fuel than they consume
(d) are unmoderated
(e) use water as coolant.
Ans: e
49. Uranium-233 is produced
(a) as basic raw material
(b) by neutron irradiation of Uz
(c) by neutron irradiation of thorium
(d) artificially
(e) in high capacity furnaces.
Ans: c
50. Plutonium-239 is produced
(a) as basic raw material
(b) by neutron irradiation of IT*
(c) by neutron irradiation of thorium
(d) artificially
(e) in high capacity furnaces.
Ans: b
51. Which of the following type of pump is used in
liquid metal cooled reactor for circulation of liquid
metal
(a) centrifugal
(b) axial
(c) reciprocation
(d) electromagnetic
(e) diaphragm.
Ans: d
52. Which of the following is the primary fuel
(a) Ulii
(b) U
(c) U238
(d) Pu:
(e) Pu
Ans: b
53. Which of the following is secondary fuel
(a) Th232andU238
(b) U233andPu239
(c) U233andPu238
Ans: c
54. A pressurised water reactor employs
pressuriser for the following application
(a) to maintain constant pressure in primary circuit
under varying load
(b) to Supply high pressure steam
(c) to increase pressure of water in primary circut
(d) to provide subcooled water at high pressure
(e) all of the above.
Ans: a
55. Which of the following can be used as a coolant
in nuclear plant
(a) light or heavy water
(b) molten lead
(c) carbon dioxide
(d) freon
(e) carbon tetrachloride.
Ans: a
56. Reactors for propulsion applications use
(a) natural uranium
(b) molten lead
(c) any form of uranium
(d) thorium
(e) plutonium.
Ans: b
57. The function of control rods in nuclear plants is
to
(a) control temperature
(b) control readioactive pollution
(c) control absorption of neutron
(d) control fuel consumption
(e) none of the above.
Ans: c
58. Breeder reactors employ liquid metal coolant
because it
(a) acts as good moderator
(b) produces maximum steam
(c) transfers heat from core at a fast rate
(d) breeds neutrons
(e) increases rate of reaction in core.
Ans: c
59. In triggering fission, which type of neutrons are
more effective
(a) fast
(b) slow
(c) in bulk
(d) static
(e) activated.
Ans: b
60. For economical operation of a nuclear plant
(a) used fuel should be reprocessed
(b) moderator should be used
(c) coolant should be employed
(d) control rods should be used
(e) reflector should be used.
Ans: a
61. The size of the reactor is said to be critical
when
(a) chain reaction can be initiated
(b) it becomes uncontrollable
(c) it explodes
(d) it produces no power
(e) it produces tremendous power.
Ans: a
62. When a reactor becomes critical, then the
production of neutrons is
(a) infinite
(b) zero
(c) exactly balanced by the loss of neutrons through
leakage
(d) initiated
(e) stopped.
Ans: c
63. In the breeder reactors the generation of new
fissionable atom is
(a) at the lower rate than the consumption
(b) at a higher rate than the constuption
(c) at an equal rate of the consumption
(d) depends on other considerations
(e) unpredictable.
Ans: b
64. The energy produced by a thermal reactor of
same size as a breeder reactor is
(a) almost same
(b) slightly more
(c) slightly less
(d) much less
(e) much more.
Ans: d
65. Reactors designed for propulsion applications
are designed for
(a) natural uranium
(b) enriched uranium
(c) pure uranium
(d) any type of uranium
(e) none of the above.
Ans: b
66. Supertheated steam is generated in following
reactor
(a) boiling water
(b) gas cooled
(c) pressurised water
(d) all of the above
(e) none of the above.
Ans: b
67. Solid- fuel for nuclear reactions may be
fabricated into various small shapes such as
(a) plates
(b) pallets
(c) pins
(d) any one of the above
(e) none of the above.
Ans: d
68. Which of the following is more appropriate for a
moderator. One which
(a) does not absorb neutrons
(b) absorbs neutrons
(c) accelerates neutrons
(d) eats up neutrons
(e) regenerates neutrons.
Ans: a
69. A fission chain reaction in uranium can be
developed by
(a) slowing down fast neutrons so that Uz fission
continues by slow motion neutrons
(b) accelerating fast neutrons
(c) absorbing all neutrons
(d) using moderator
(e) enriching U235.
Ans: a
70. In triggering fission, the following types of
neutrons are desirable
(a) fast moving
(b) slow moving
(c) critical neutrons
(d) neutrons at rest
(e) none of the above.
Ans: b
71. Effective moderators are those materials which
contain
(a) light weight atoms
(b) heavy weight atoms
(c) critical atoms
(d) zero weight atoms
(e) there is no such criterion.
Ans: a
72. In a fission process, maximum %age of energy
is released as
(a) kinetic energy of neutrons
(b) kinetic energy of fission products
(c) instantaneous release of gamma rays
(d) gradual readioactive decay of fission products
(e) none of the above.
Ans: b
73. The following present serious difficulty in
designing reactor shield
(a) alpha particles
(b) beta particles
(c) thermal neutrons
(d) fast neutrons and gamma rays
(e) none of the above.
Ans: d
74. In nuclear fission
(a) the original elements change into completely
different elements
(b) the electrons of the element change
(c) the molecules rearrange themselves to form
other molecules
(d) none of the above.
Ans: a
75. In order to have constant clain reaction to
produce a constant rate of heat output, the value of
ratio of the number of neutrons in one generation to
the number of neutrons in the immediately
preceding generation must be
(a) greater than 1.0
(b) less than 1.0
(c) equal to zero
(c) equal to 1.0
(e) equal to infinity.
Ans: d
75. Each fission of U235 produces following number
of fast neutrons per fission
(a) 1 neutron
(b) 1 — neutrons
(c) 1 - 2 neutrons
(d) 2 — neutrons
(e) infinite.
Ans: d
76. A fast breeder reactor uses following as fuel
(a) enriched uranium
(b) plutonium
(c) thorium
(d) U235
(e) natrual uranium.
Ans: d
77. A boiling water reactor uses following as fuel
(a) enriched uranium
(b) plutonium
(c) thorium
(d) U
(e) natural uranium.
Ans: a
78. A fast breeder reactor
(a) uses graphite rods as moderator
(b) has powerful moderator
(c) has no moderator
(d) uses ferrite material as moderator
(e) uses pressurised water as moderator.
Ans: c
79. Artificial radioactive isotopes find application in
(a) power generation
(b) nucleonic devices
(c) nuclear fission
(d) nuclear fusion
(e) medical field.
Ans: e
80. A fast breeder reactor uses
(a) 90% U-235
(b) U-238
(c) U-235
(d) Pu-239
(e) U-239.
Ans: a
81. Half life of a radioactive isotope corresponds to
the time required for half of the following to decay
(a) electrons
(b) protons
(c) neutrons
(d) nulceus
(e) atom.
Ans: e
82. Pressurised water reactor isdesigned
(a) for boiling pi water in the core
(b) to use liquid sodium metal as coolant
(c) to use intermediate coolant
(d) to prevent the water coolant from boiling in the
core
(e) to eliminate the coolant loop of the pressurised
water.
Ans: d
83. The coolant used in boiling water reactor is
(a) Co2
(b) pressurised water
(c) mixture of water and steam
(d) liquid metal
(e) mercury.
Ans: c
84. In boiling water reactor, moderator is
(a) coolant itself
(b) ferrite rod
(c) graphite rod
(d) liquid sodium metal
(e) blanket of thorium.
Ans: a
85. The most practical fuel for a thermo-nuclear
reactor, both from econocical and nuclear
consideration is
(a) plutonium
(b) uranium
(c) deuterium
(d) thorium
(e) lithium.
Ans: c
86. The efficiency of a nuclear power plant in
comparison to conventional and nuclear
consideration is
(a) higher cost of nuclear fuel
(b) high initial cost
(c) high heat rejection in condenser
(d) lower temperature and pressure condi-tions
(e) nuclear hazard risk.
Ans: d
87. The presence of reflector in nuclear power
plants results in
(a) increased production of neutrons
(b) complete absorption of neutrons
(c) controlled production of neutrons
(d) decreased leakage of neutrons
(e) decrease of speed of neutrons.
Ans: d
88. The fuel needed, with reflector in nuclear power
plant, in order to generate sufficient neutrons to
sustain a chain reaction, would be
(a) more
(b) less
(c) same
(d) zero
(e) negative, i.e. fuel would be generated.
Ans: b