Power Plant Engineering Objective Questions Part – 5
1.In India largest thermal power station is located at
Kota
Sarni
Chandrapur
Neyveli
ANSWER : : Chandrapur
2.In a regenerative feed heating cycle, the greatest economy is affected
when steam is extracted from only one suitable point of steam turbine
when steam is extracted from several places in different stages of steam turbine
when steam is extracted only from the last stage of steam turbine
when steam is extracted only from the first stage of steam turbine
ANSWER : : when steam is extracted from several places in different stages of steam turbine
3.Thorium Breeder Reactors are most suitable for India because
these develop more power
its technology is simple
abundance of thorium deposits are available in India
these can be easily designed
ANSWER : : abundance of thorium deposits are available in India
4.The maximum percentage gain in Regenerative feed heating cycle thermal efficiency
increases with number of feed heaters increasing
decreases with number of feed heaters increasing
remains same unaffected by number of feed heaters
none of the above
ANSWER : : increases with number of feed heaters increasing
5.Regenerative cycle thermal efficiency
is always greater than simple Rankine thermal efficiency
is greater than simple Rankine cycle thermal efficiency only when steam is bled
rticular pressure
is same as simple Rankine cycle thermal efficiency
ANSWER : 4 is always less than simple Rankine cycle thermal efficiency
6.India’s first nuclear power plant was installed at
Tarapore
Kota
Kalpakkam
none of the above
ANSWER : : Tarapore
7.The main source of production of biogas is
human waste
wet cow dung
wet livestock waste
all above
ANSWER : : all above
8.The percentage O2 by Veight in atmospheric air is
18%
23%
77%
79%
ANSWER : : 23%
9.The proper indication of incomplete combustion is
high CO content in flue gases at exit
high CO2 content in flue gases at exit
high temperature of flue gases
the smoking exhaust from chimney
ANSWER : : high CO content in flue gases at exit
10.In fuel cell, the ______ energy is converted into electrical energy.
mechanical
chemical
heat
sound
ANSWER : : chemical
11.Rankine efficiency of a steam power plant
improves in summer as compared to that in winter
improves in winter as compared to that in summer
is unaffected by climatic conditions
none of the above
ANSWER : : improves in winter as compared to that in summer
12.Rankine cycle efficiency of a good steam power plant may be in the range of
15 to 20 per cent
35 to 45 per cent
70 to 80 per cent
90 to 95 per ceut
ANSWER : : 35 to 45 per cent
13.In Rankine cycle the work output from the turbine is given by
change of internal energy between inlet and outlet
change of enthaply between inlet and outlet
change of entropy between inlet and outlet
change of temperature between inlet and outlet
ANSWER : : change of enthaply between inlet and outlet
14.Solar thermal power generation can be achieved by
using focusing collector or heliostates
using flat plate collectors
using a solar pond
any of the above system
ANSWER : : any of the above system
16.Carnot cycle comprises of
two isentropic processes and two constant volume processes
two isentropic processes and two constant pressure processes
two isothermal processes and three constant pressure processes
none of the above
ANSWER : : two isentropic processes and two constant pressure processes
17.The percentage 02 by volume in atmosphere air is
21%
23%
77%
79%
ANSWER : : 21%
18.Mercury is a choice with steam in binary vapour cycle because it has
higher critical temperature and pressure
higher saturation temperature than other fluids
relatively low vapourisation pressure
all above
ANSWER : : all above
19.In regenerative cycle feed water is heated by
exhaust gases
heaters
draining steam from the turbine
all above
ANSWER : : draining steam from the turbine
20.In a regenerative feed heating cycle, the optimum value of the fraction of steam extracted for feed heating
decreases with increase in Rankine cycle efficiency
increases with increase in Rankine cycle efficiency
is unaffected by increase in Rankine cycle efficiency
none of the above
ANSWER : : increases with increase in Rankine cycle efficiency
21.The overall efficiency of thermal power plant is equal to
Rankine cycle efficiency
Carnot cycle efficiency
Regenerative cycle efficiency
Boiler efficiency x turbine efficiency x generator efficiency
ANSWER : : Regenerative cycle efficiency
22.Reheat cycle in steam power plant is used to
utilise heat of flue gases
increase thermal efficiency
improve condenser performance
reduce loss of heat
ANSWER : : increase thermal efficiency
23.The energy radiated by sun on a bright sunny day is approximately
700 W/m2
800 W/m2
1 kW/m2
2 kW/m2
ANSWER : : 1 kW/m2
24.Rankine cycle operating on low pressure limit ofpi an 1 high pressure limit of p2
has higher the rnal efficiency than the carnot cycie operating between same
ure limits
has lower the”nal efficiency than carnot cycle operating between same pressure
?
ANSWER : 3 has same thermal efficiency as carnot cycle operating between same pressure limits
25.The ratio of exit pressure to inlet pressure of maximum mass flow rate per area of steam through a nozzle when steam is initially superheated is
0.555
0.578
0.5457
0.6
ANSWER : : 0.5457
26.For the induced draught the fan is located
near bottom of chimney
near bottom of furnace
at the top of the chimney
anywhere permissible
ANSWER : : near bottom of chimney
27.Artificial draught is produced by
air fans
steam jet
fan or steam jet
all of the above
ANSWER : : all of the above
28.The effect of considering friction losses in steam nozzle for the same pressure ratio leads to
increase in exit velocity from the nozzle
decrease in exit velocity from the nozzle
no change in exit velocity from the nozzle
increase or decrease depending upon the exit quality of steam
ANSWER : : decrease in exit velocity from the nozzle
29.The draught produced, for a given height of the chimney and given mean temperature of chimney gases
decreases with increase in outside air temperature
increases with increase in outside air temperature
remains the same irrespective of outside air temperature
may increase or decrease with increase in outside air temperature
ANSWER : : decreases with increase in outside air temperature
30.The draught produced by chimney of given height at given outside temperature
decreases if the chimney gas temperature increases
increases if the chimney gas temperature increases
remains same irrespective of chimney gas temperature
may increase or decrease
ANSWER : : increases if the chimney gas temperature increases
31.The artificial draught normally is designed to produce
less smoke
more draught
less chimney gas temperature
all of the above
ANSWER : : all of the above
32.The critical pressure ratio of a convergent nozzle is defined as
the ratio of outlet pressure to inlet pressure of nozzle
the ratio of inlet pressure to outlet pressure of nozzle
the ratio of outlet pressure to inlet pressure only when mass flow rate per unit area
ANSWER : 4 the ratio of outlet pressure to inlet pressure only when mass flow rate = c
33.The efficiency of chimney is approximately
80%
40%
20%
0.25%
ANSWER : : 0.25%
34.The isentropic expansion of steam through nozzle for the steam initially superheated at inlet is approximated by equation
pvls=C
pv1126 = C
pv1A = C
pv = C
ANSWER : : pvls=C
35.The draught in locomotive boilers is produced by
forced fan
chimney
steam jet
only motion of locomotive
ANSWER : : steam jet
36.The effect of considering friction in steam nozzles for the same pressure ratio leads to
increase in dryness fraction of exit steam
decrease in dryness fraction of exit steam
no change in the quality of exit steam
decrease or increase of dryness frac-tion of exit steam depending upon inlet
ANSWER : lity
37.The ratio of exit pressure to inlet pressure for maximum mass flow rate per unit area of steam through a nozzle when steam is initially dry saturated is
0.6
0.578
0.555
0.5457
ANSWER : : 0.578
38.In a boiler installation the natural draught is produced
due to the fact that furnace gases being light go through the chimney giving place
ld air from outside to rush in
due to the fact that pressure at the grate due to cold column is higher than the
ure at the chimney base due to hot column
ANSWER : 3 due to the fact that at the chimney top the pressure is more than its
39.The pressure at the furnace is minimum in case of
forced draught system
induced draught system
balanced draught system
natural draught system
ANSWER : : balanced draught system
40.For forced draught system, the function of chimney is mainly
to produce draught to accelerate the combustion of fuel
to discharge gases high up in the atmosphere to avoid hazard
to reduce the temperature of the hot gases discharged
none of the above
ANSWER : : to discharge gases high up in the atmosphere to avoid hazard
41.The draught which a chimney produces is called
induced draught
natural draught
forced draught
balanced draught
ANSWER : : natural draught
42.For the same draught produced the power of induced draught fan as compared to forced draught fan is
less
more
same
not predictable
ANSWER : : more
44.The modern steam turbines are
impulse turbines
reaction turbines
impulse-reaction turbines
none of the above
ANSWER : : impulse-reaction turbines
45.A steam power station requires space
equal to diesel power station
more than diesel power station
less than diesel power station
more than diesel power station
ANSWER : Economiser is used to heat
46.The draught produced by steel chimney as compared to that produced by brick chimney for the same height is
less
more
same
may be more or less
ANSWER : : more
47.The isentropic expansion of steam through nozzle for the steam initially dry saturated at inlet is approximated by equation.
pv = C
pv1A = C
pv1i = C
pv
ANSWER : : pv
48.Artificial draught is produced by
induced fan
forced fan
induced and forced fan
all of the above
ANSWER : : all of the above
49.Evaporative type of condenser has
steam in pipes surrounded by water
water in pipes surrounded by steam
either (a) or (b)
none of the above
ANSWER : : steam in pipes surrounded by water
50.In a shell and tube surface condenser
steam and cooling water mix to give the condensate
cooling water passes through the tubes and steam surrounds them
steam passes through the cooling tubes and cooling water surrounds them
all of the above varying with situa�tion
ANSWER : : cooling water passes through the tubes and steam surrounds them
51.The pressure on the two sides of the impulse wheel of a steam turbine
is same
is different
increases from one side to the other side
decreases from one side to the other side
ANSWER : : is same
52.Incase of reaction steam turbine
there is enthalpy drop both in fixed and moving blades
there is enthalpy drop only in fixed blades
there is enthalpy drop only in moving blades
none of the above
ANSWER : : there is enthalpy drop both in fixed and moving blades
53.In a steam power plant, the function of a condenser is
to maintain pressure below atmospheric to increase work output from the primemover
to receive large volumes of steam exhausted from steam prime mover
to condense large volumes of steam to water which may be used again in boiler
all of the above
ANSWER : : all of the above
54.In a regenerative surface condenser
there is one pump to remove air and condensate
there are two pumps to remove air and condensate
there are three pumps to remove air, vapour and condensate
there is no pump, the condensate gets removed by gravity
ANSWER : : there are two pumps to remove air and condensate
55.Rateau steam turbine is
reaction steam turbine
velocity compounded impulse steam turbine
pressure compounded impulse steam turbine
pressure velocity compounded steam turbine
ANSWER : : pressure compounded impulse steam turbine
56.The thermal efficiency of the engine with condenser as compared to without condenser, for a given pressure and temperature of steam, is
higher
lower
same as long as initial pressure and temperature is unchanged
none of the above
ANSWER : : higher
57.For Parson’s reaction steam turbine, degree of reaction is
75%
100%
50%
60%
ANSWER : : 50%
58.In De Laval steam turbine
the pressure in the turbine rotor is approximately same as in con�denser
the pressure in the turbine rotor is higher than pressure in the con�denser
the pressure in the turbine rotor gradually decreases from inlet to exit from
nser
ANSWER : 4 none from the above
59.Pipes carrying steam are generally made up of
steel
cast iron
copper
aluminium
ANSWER : : steel
60.Edward’s air pump
removes air and also vapour from condenser
removes only air from condenser
removes only un-condensed vapour from condenser
removes air alongwith vapour and also the condensed water from condenser
ANSWER : : removes air alongwith vapour and also the condensed water from condenser
61.In jet type condensers
cooling water passes through tubes and steam surrounds them
steam passes through tubes and cooling water surrounds them
steam and cooling water mix
steam and cooling water do not mix
ANSWER : : steam and cooling water mix
62.In a surface condenser if air is removed, there is
fall in absolute pressure maintained in condenser
rise in absolute pressure maintained in condenser
no change in absolute pressure in the condenser
rise in temperature of condensed steam
ANSWER : : fall in absolute pressure maintained in condenser
63.The value of reheat factor normally varies from
0.5 to 0.6
0.9 to 0.95
1.02 to 1.06
1.2 to 1.6
ANSWER : : 1.02 to 1.06
64.Parson’s turbine is
pressure compounded steam turbine
simple single wheel, impulse steam turbine
simple single wheel reaction steam turbine
multi wheel reaction steam turbine
ANSWER : : multi wheel reaction steam turbine
65.Steam turbines commonly used in steam power station are
condensing type
non-condensing type
none of the above
condensing type
ANSWER : Belt conveyer can be used to transport coal at inclinations upto
66.Curtis turbine is
reaction steam turbine
pressure velocity compounded steam turbine
pressure compounded impulse steam turbme
velocity compounded impulse steam turbine
ANSWER : : pressure velocity compounded steam turbine
67.In steam turbines the reheat factor
increases with the increase in number of stages
decreases with the increase in number of stages
remains same irrespective of num�ber of stages
none of the above
ANSWER : : increases with the increase in number of stages
68.The cooling section in the surface condenser
increases the quantity of vapour extracted along with air
reduces the quantity of vapour extracted along with air
does not affect vapour quantity extracted but reduces pump capacity of air
ction pump
ANSWER : 4 none of the above
69.Steam turbines are governed by the following methods
Throttle governing
Nozzle control governing
By-pass governing
all of the above
ANSWER : : all of the above
70.Reheat factor in steam turbines depends on
exit pressure only
stage efficiency only
initial pressures and temperature only
all of the above
ANSWER : : initial pressures and temperature only
71.For the safety of a steam boiler the number of safety valves fitted are
four
three
two
one
ANSWER : : two
72.Bucket elevators are used for
carrying coal in horizontal direction
carrying coal in vertical direction
carrying coal in any direction
carrying coal in vertical direction
ANSWER : The amount of air which is supplied for complete combustion is called
74.Caking coals are those which
burn completely
burn freely
do not form ash
form lumps or masses of coke
ANSWER : : form lumps or masses of coke
75.In ______ system fuel from a central pulverizing unit is delivered to a bunker and then to the various burners
unit
central
none of the above
central
ANSWER : Under-feed stokers work best for _______ coals high in volatile matter and with
76.Economisers improve boiler efficiency by
1 to 5%
4 to 10%
10 to 12%
4 to 10%
ANSWER : The capacity of large turbo-generators varies from
77.Method which is commonly applied for unloading the coal for small power plant is
lift trucks
coal accelerators
tower cranes
belt conveyor
ANSWER : : coal accelerators
78.Primary air is that air which is used to
reduce the flame length
increase the flame length
transport and dry the coal
provide air around burners for get�ting optimum combustion
ANSWER : : transport and dry the coal
79.Deaerative heating is done to
heat the water
heat the air in the water
remove dissolved gases in the water
remove dissolved gases in the water
ANSWER : eheat factor is the ratio of
80.Secondary air is the air used to
reduce the flame length
increase the flame length
transport and dry the coal
provide air round the burners for getting optimum combustion
ANSWER : : provide air round the burners for getting optimum combustion
81.Blowing down of boiler water is the process
to reduce the boiler pressure
to increase the steam temperature
to control the solid concentration in the boiler water by removing some of the
ntrated saline water
ANSWER : 4 none of the above
82.Compounding of steam turbine is done for
reducing the work done
increasing the rotor speed
reducing the rotor speed
balancing the turbine
ANSWER : : reducing the rotor speed
83.Where unpulverised coal has to be used and boiler capacity is large, the stoker which is used is
underfeed stoker
overfeed stoker
any
overfeed stoker
ANSWER : ravelUng grate stoker can burn coals at the rates of
84.In coal preparation plant, magnetic separators are used to remove
dust
clinkers
iron particles
sand
ANSWER : : iron particles
85.Load centre in a power station is
centre of coal fields
centre of maximum load of equip-ments
centre of gravity of electrical system
centre of gravity of electrical system
ANSWER : Steam pressure in a steam power station, which is usually kept now-a-days is of
86.The value of the reheat factor is of the order of
0.8 to 1.0
1.0 to 1.05
1.1 to 1.5
above 1.5
ANSWER : : 1.1 to 1.5
87.The efficiency of a modern boiler using coal and heat recovery equipment is about
25 to 30%
40 to 50%
65 to 70%
85 to 90%
ANSWER : : 85 to 90%
88.Load carrying capacity of belt conveyor is about
20 to 40 tonnes/hr
50 to 100 tonnes/hr
100 to 150 tonnes/hr
150 to 200 tonnes/hr
ANSWER : : 50 to 100 tonnes/hr
89.The average ash content in Indian co als is about
5%
10%
15%
20%
ANSWER : : 20%
90.Example of overfeed type stoker is
chain grate
spreader
travelling grate
all of the above
ANSWER : : all of the above