"Mechanical Question"
Thermodynamics
1.Which of the following variables
controls the physical properties of a perfect gas
(a) pressure
(b) temperature
(c) volume
(d) all of the above
(e) atomic mass.
Ans: d
2.Which of the following laws is
applicable for the behavior of a perfect gas
(a)Boyle's law
(b)Charles'law
(c)GayLussac law
(d)all of the above
(e)Joule's law.
Ans: d
3.The unit of temperature in S.I. units is
(a) Centigrade
(b) Celsius
(c) Fahrenheit
(d) Kelvin
(e) Rankine.
Ans: d
4.The unit of mass in S.I. units is
(a)kilogram
(b)gram
(c)tonne
(d)quintal
(e)newton.
Ans: a
5.The unit of time in S.I. units is
(a) second
(b) minute
(c) hour
(d) day
(e) year.
Ans: a
6.The unit of length in S.I. units is
(a) meter
(b) centimeter
(c) kilometer
(d) millimeter.
Ans: a
7.The unit of energy in S.I. units is
(a) watt
(b)joule
(c)joule/s
(d)joule/m
(e)joule m.
Ans: b
8. According to GayLussac law for a perfect gas, the
absolute pressure of given mass varies directly as
(a)temperature
(b)absolute
(c)absolute temperature, if volume is kept
constant
(d)volume, if temperature is kept constant
(e)remains constant,if volume and
temperature are kept constant.
Ans: c
9. An ideal gas as compared to a real gas at very high
pressure occupies
(a)more volume
(b)less volume
(c)same volume
(d)unpredictable behaviour
(e)no such correlation.
Ans: a
10.General gas equation is
(a) PV=nRT
(b) PV=mRT
(d) PV = C
(c) PV=KiRT
(e) CpCv = Wj
Ans: b
11.According to Dalton's law, the total
pres sure of the mixture of gases is equal to
(a) greater of the
partial pressures of all
(b) average of the
partial pressures of all
(c) sum of the partial
pressures of all
(d) sum of the partial
pressures of all divided by average molecular weight
(e) atmospheric
pressure.
Ans: c
12.Which of the following can be regarded
as gas so that gas laws could be applicable, within the commonly encountered
temperature limits.
(a) 02, N2, steam, C02
(b) Oz, N2, water vapour
(c) S02, NH3, C02,
moisture
(d) 02, N2, H2, air
(e) steam vapours, H2,
C02.
Ans: d
13.The unit of pressure in S.I. units is
(a)kg/cm2
(b)mm of water column
(c)pascal
(d)dynes per square cm
(e)bars
Ans: c
14. A closed system is one in which
(a)mass does not cross boundaries of the
system, though energy may do so
(b)mass crosses the boundary but not the
energy
(c)neither mass nor energy crosses the
boundaries of the system
(d)both energy and mass cross the
boundaries of the system
(e)thermodynamic reactions take place.
Ans: a
15.Temperature of a gas is produced due to
(a) its heating value
(b) kinetic energy of
molecules
(c) repulsion of
molecules
(d) attraction of
molecules
(e) surface tension of
molecules.
Ans: b
16.According to kinetic theory of gases,
the absolute zero temperature is attained when
(a) volume of the gas is
zero
(b) pressure of the gas
is zero
(c) kinetic energy of
the molecules is zero
(d) specific heat of gas is zero
(e) mass is zero.
Ans: c
17.Kinetic theory of gases assumes that the
collisions between the molecules are
(a) perfectly elastic
b)perfectly inelastic
(c)partly elastic
(d)partly inelastic
(e)partly elastic and partly inelastic.
Ans: a
18.The pressure'of a gas in terms of its
mean kinetic energy per unit volume E is equal to
(a) E/3
(b) E/2
(c) 3E/4
(d)2E/3
(e) 5E/4.
Ans: d
19.Kinetic energy of the molecules in terms
of absolute temperature (T) is proportional to
(a) T
(b) j
(c) J2
(d) Vr
(e) 1/Vr.
Ans: a
20.Superheated vapour behaves
(a)exactly as gas
(b)as steam
(c)as ordinary vapour
(d)approximately as a gas
(e)as average of gas and vapour.
Ans: d
21.Absolute zero pressure will occur
(a) at sea level
(b) at the center of the
earth
(c) when molecular
momentum of the system becomes zero
(d) under vacuum
conditions
(e) at a temperature of
273 °K
Ans: c
22.No liquid can exist as liquid at
(a) 273 °K
(b)vacuum
(c)zero pressure
(d)centre of earth
(e)in space.
Ans: c
23.The unit of power in S.I. units is
(a) newton
(b) pascal
(c) erg
(d) watt
(e) joule.
Ans: d
24.The condition of perfect vacuum, i.e.,
absolute zero pressure can be attained at
(a) a temperature of
273.16°C
(b) a temperature of 0°C
(c) a temperature of 273
°K
(d) a negative pressure
and 0°C temperature
(e) can't be attained
. Ans: a
25.Intensive property of a system is one
whose value
(a)depends on the mass of the system, like
volume
(b)does not depend on the mass of the
system, like temperature, pressure, etc.
(c)is not dependent on the path followed
but on the state
(d)is dependent on the path followed and
not on the state
(e)remains constant.
Ans: b
26.Specific heat of air at constant
pressure is equal to
(a) 0.17
(b) 0.21
(c) 0.24
(d) 1.0
(e) 1.41
Ans: c
27.Characteristic gas constant of a gas is
equal to
(a)C/Cv
(b)Cv/Cp
(c)Cp Cv
(d)Cp + Cv
(e)Cp x Cv
Ans: c
28.The behaviour of gases can be fully
determined by
(a) 1 law
(b) 2 laws
(c) 3 laws
(d) 4
laws
Ans: d
29.The ratio of two specific heats of air
is equal to
(a) 0.17
(b) 0.24
(c) 0.1
(d) 1.41
(e) 2.71. Ans: d
30.Boyle's law i.e. pV = constant is
applicable to gases under
(a) all ranges of
pressures
(b) only small range of
pressures
(c) high range of pressures
(d) steady change of
pressures
(e) atmospheric
conditions. Ans: b
31.Which law states that the internal
energy of a gas is a function of temperature
(a) Charles' law
(b) Joule's law
(c) Regnault's law
(d) Boyle's law
(e) there is no such
law. Ans: b
32.The same volume of all gases would
represent their
(a)densities
(b)specific weights
(c)molecular weights
(d)gas characteristic constants
(e)specific gravities.
Ans: c
33.Which law states that the specific heat
of a gas remains constant at all temperatures and pressures
(a) Charles' Law
(b) Joule's Law
(c) Regnault's Law
(d) Boyle's Law
(e) there is no such
law. Ans: c
34.An open system is one in which
(a)mass does not cross boundaries of the
system, though energy may do so
(b)neither mass nor energy crosses the
boundaries of the system
(c)both energy and mass cross the
boundaries of the system
(d)mass crosses the boundary but not the
energy
(e)thermodynamic reactions do not occur.
Ans: c
35.According to which law, all perfect
gases change in volume by l/273th of their original volume at 0°C for every 1°C
change in temperature when pressure remains constant
(a) Joule's law
(b) Boyle's law
(c) Regnault's law
(d) GayLussac law
(e) Charles' law. Ans: e
36.Gases have
(a)only one value of specific heat
(b)two values of specific heat
(c)three values of specific heat
(d)no value of specific heat
(e)under some conditions one value and
sometimes two values of specific heat. Ans: b
37. According to Avogadro's Hypothesis
(a)the molecular weights of all the perfect
gases occupy the same volume under same conditions of pressure and temperature
(b)the sum of partial pressure of mixture
of two gases is sum of the two
(c)product of the gas constant and the
molecular weight of an ideal gas is constant
(d)gases have two values of specific heat
(e)all systems can be regarded as closed
systems.
Ans: a
38.Extensive property of a system is one
whose value
(a) depends on the mass
of the system like volume
(b) does not depend on
the mass of the system, like temperature, pressure, etc.
(c) is not dependent on
the path followed but on the state
(d) is dependent on the
path followed and not on the state
(e) is always constant.
Ans: a
39.Work done in a free expansion process is
(a)+ ve
(b)ve
(c)zero
(d)maximum
(e)minimum. Ans: c
40.The statement that molecular weights of
all gases occupy the same volume is known as
(a) Avogadro's
hypothesis
(b) Dalton's law
(c) Gas law
(d) Law of
thermodynamics
(e) Joule's law. Ans: a
41.To convert volumetric analysis to
gravimetric analysis, the relative volume of each constituent of the flue gases
is
(a) divided by its molecular weight
(b) multiplied by its
molecular weight
(c) multiplied by its
density
(d) multiplied by its
specific weight
(e) divided by its
specific weight. Ans: b
42.If a gas is heated against a pressure,
keeping the volume constant, then work done will be equal to
(a)+ v
(b) ve
(c)zero
(d)pressure x volume
(e)any where between zero and infinity.
Ans: c
43. An isolated system is one in which
(a)mass does not cross boundaries of the
system, though energy may do so
(b)neither mass nor energy crosses the
boundaries of the system
(c)both energy and mass cross the
boundaries of the system
(d)mass crosses the boundary but not the
energy
(e)thermodynamic reactions do not occur.
Ans: b
44.Properties of substances like pressure,
temperature and density, in thermodynamic coordinates are
(a) path functions
(b) point functions
(c) cyclic functions
(d) real functions
(e) thermodynamic
functions. Ans: b
45.Which of the following quantities is not
the property of the system
(a)pressure
(b)temperature
(c)specific volume
(d)heat
(e)density.
Ans: d
46.According to Avogadro's law, for a given
pressure and temperature, each molecule of a gas
(a) occupies volume
proportional to its molecular weight
(b) occupies volume
proportional to its specific weight
(c) occupies volume
inversely proportional to its molecular weight
(d) occupies volume
inversely proportional to its specific weight
(e) occupies same
volume. Ans: e
47.Mixture of ice and water form a
(a)closed system
(b)open system
(c)isolated system
(d)heterogeneous system
(e)thermodynamic system. Ans: d
48. Which of the following is the property of a system
(a)pressure and temperature
(b)internal energy
(c)volume and density
(d)enthalpy and entropy
(e)all of the above.
Ans: e
49.On weight basis, air contains following
parts of oxygen
(a) 21
(b) 23
(c) 25
(d) 73
(e) 79. Ans: b
50.Which of the following is not the
intensive property
(a) pressure
(b) temperature
(c) density
(d) heat
(e) specific volume.
Ans: d
51.Which of the following items is not a
path function
(a)heat
(b)work
(c)kinetic energy
(d)vdp
(e)thermal conductivity. Ans: e
52.Work done in an adiabatic process
between a given pair of end states depends on
(a) the end states only
(b) particular adiabatic
process
(c) the value of index n
(d) the value of
heattransferred
(e) mass of the system.
Ans: a
53.Heat and work are
(a)point functions
(b)system properties
(c)path functions
(d)intensive properties
(e)extensive properties. Ans: c
54.Which of the following parameters is
constant for a mole for most of the gases at a given temperature and pressure
(a) enthalpy
(b) volume
(c) mass
(d) entropy
(e) specific volume.
Ans: b
55.The value of n = 1 in the polytropic
process indicates it to be
(a)reversible process
(b)isothermal process
(c)adiabatic process
(d)irreversible process
(e)free expansion process. Ans: b
56. Solids and liquids have
(a) one value of specific heat (ft) two values of
specific heat
(c)three values of specific heat
(d)no value of specific heat
(e)one value under some conditions and two
values under other conditions. Ans: a
57. A perfect gas at 27°C is heated at constant pressure
till its volume is double. The final temperature is
(a)54°C
(b)327°C
(c)108°C
(d)654°C
(e)600°C
Ans: b
58.Curve A in Fig. 1.1 compared to curves B
and C shows the following type of expansion
(a) pV"=C
(b) isothermal
(c) adiabatic
(d) free expansion
(e) throttling. Ans: b
59.If value of n is infinitely large in a
polytropic process pV" = C, then the process is known as constant
(a) volume
(b) pressure
(c) temperature
(d) enthalpy
(e) entropy. Ans: a
60.The index of compression n tends to
reach ratio of specific heats y when
(a)flow is uniform and steady
(b)process is isentropic
(c)process is isothermal
(d)process is isentropic and specific heat
does not change with temperature
(e)process is isentropic and specific heat
changes with temperature.
Ans: d
61.Change in enthalpy of a system is the
heat supplied at
(a) constant pressure
(b) constant temperature
(c) constant volume
(d) constant entropy
(e) N.T.P. condition.
Ans: a
62.The term N.T.P. stands for
(a)nominal temperature and pressure
(b)natural temperature and pressure
(c)normal temperature and pressure
(d)normal thermodynamic practice
(e)normal thermodynamic pressure. Ans: c
63.A heat exchange process in which the
product of pressure and volume remains constant is known as
(a) heat exchange
process
(b) throttling process
(c) isentropic process
(d) adiabatic process
(e) hyperbolic process.
Ans: e
64.In an isothermal process, the internal
energy of gas molecules
(a)increases
(b)decreases
(c)remains constant
(d)may increase/decrease depending on the
properties of gas
(e)shows unpredictable behaviour.
Ans: c
65. Zeroth law of thermodynamics
(a)deals with conversion of mass and energy
(b)deals with reversibility and
irreversibility of process
(c)states that if two systems are both in
equilibrium with a third system, they are in thermal equilibrium with each
other
(d)deals with heat engines
(e)does not exist.
Ans: c
66.If a certain amount of dry ice is mixed
with same amount of water at 80°C, the final temperature of mixture will be
(a) 80°C
(b) 0°C
(c) 40°C
(d) 20°C
(e) 60°C. Ans: b
67.The basis for measuring thermodynamic
property of temperature is given by
(a)zeroth law of thermodynamics
(b)first law of thermodynamics
(c)second law of thermodynamics
(d)third law of thermodynamics
(e)Avogadro's hypothesis.
Ans: a
68.One
watt is equal to
(a)
1 Nm/s
(b)
1 N/mt
(c)
1 Nm/hr
(d)
1 kNm/hr
(e)
1 kNm/mt. Ans: a
69.Work done is zero
for the following process
(a)
constant volume
(b)
free expansion
(c)
throttling
(d)
all Of the above
(e)
none of the above. Ans: d
70.For which of the
following substances, the gas laws can be used with minimum error
(a)
dry steam
(b)
wet steam
(c)
saturated steam
(d)
superheated steam
(e)
steam at atmospheric pressure. Ans: d
71.In a nonflow
reversible process for which p = ( 3V+ 15) x 105N/m2,V changes from 1 m to 2
m3. The work done will be about
(a)
100 xlOO5 joules
(b)
lxlO5 joules
(c)
10 xlO5 joules
(d) 10 xlO5 kilo
joules
(e)
10xl04ki\ojoules. Ans: c
72.The value of the
product of molecular weight and the gas characteristic constant for all the
gases in M.K.S. unit is
(a)29.27
kgfm/mol°K
(b)8314kgfm/mol°K
(c)848kgfm/mol°K
(d)427kgfm/mol°K
(e)735
kgfm/mol°K. Ans: c
73.On volume basis,
air contains following parts of oxygen
(a)
21
(b)
23
(c)
25
(d)
77
(e)
79. Ans: a
74.Universal gas
constant is defined as equal to product of the molecular weight of the gas and
(a)
specific heat at constant pressure
(b)
specific heat at constant volume
(c)
ratio of two specific heats
(d)
gas constant
(e)
unity. Ans: d
75.The value of the
product of molecular weight and the gas characteristic constant for all the
gases in S.I. units is
(a)
29.27 J/kmol°K
(b)
83.14J/kmol°K
(c)
848J/kmol°K
(d)
All J/kmol °K
(e)
735 J/kmol °K. Ans: b
76.For which of the
following substances, the internal energy and enthalpy are the functions of
temperature only
(a)
any gas
(b)
saturated steam
(c)
water
(d)
perfect gas
(e)
superheated steam. Ans: d
77.In a free expansion
process
(a)work
done is zero
(b)heat
transfer is zero
(c)both (a) and (b)
above
(d)work
done is zero but heat increases
(e)work
done is zero but heat decreases. Ans: c
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78.If
a gas vapour is allowed to expand through a very minute aperture, then such a
process is known as
(a)
free expansion
(b)
hyperbolic expansion
(c)
adiabatic expansion
(d)
parabolic expansion
(e)
throttling. Ans: e
79.The specific heat
of air increases with increase in
(a)temperature
(b)pressure
(c)both
pressure and temperature
(d)variation
of its constituents
(e)air
flow
Ans: a
80.If a fluid expands
suddenly into vacuum through an orifice of large dimension, then such a process
is called
(a)
free expansion
(b)
hyperbolic expansion
(c)
adiabatic expansion
(d)
parabolic expansion
(e)
throttling. Ans: a
81.Which of the
following processes are thermodynamically reversible
(a)throttling
(b)free
expansion
(c)constant
volume and constant pressure
(d)hyperbolic
and pV = C
(e)isothermal
and adiabatic.
Ans: e
82.Which of the
following processes is irreversible process
(a)
isothermal
(b)
adiabatic
(c)
throttling
(d)
all of the above
(e)
none of the above. Ans: c
83.In order that a
cycle be reversible, following must be satisfied
(a)free
expansion or friction resisted expansion/compression process should not be
encountered
(b)when
heat is being absorbed, temperature of hot source and working sub¬stance should
be same
(c)when
beat is being rejected, temperature of cold source and working substance
should be same
(d)all
of the above
(e)none
of the above.
Ans: d
84.For a thermodynamic
process to be reversible, the temperature difference between hot body and
working substance should be
(a)
zero
(b)
minimum
(d)
maximum
(d)
infinity
(e)
there is no such criterion. Ans: a
85.Minimum work in
compressor is possible when the value of adiabatic index n is equal to
(a)0.75
(b)1
(c)1.27
(d)1.35
(e)2.
Ans: b
86.Molecular volume of
any perfect gas at 600 x 103 N/m2 and 27°C will be
(a)
4.17m3/kgmol
(b)
400 m3/kg mol
(c)
0.15 m3/kg mol
(d)
41.7 m3/kg mol
(e)
417m3/kgmol. Ans: a
87.A gas is compressed
in a cylinder by a movable piston to a volume onehalf its original volume.
During the process 300 kJ heat left the gas and internal energy remained same.
The work done on gas in Nm will be
(a)
300 Nm
(b) 300,000 Nm
(c)
30 Nm
(d)
3000 Nm
(e)
30,000 Nm.
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Ans: b
88.The more effective
way of increasing efficiency of Carnot engine is to
(a)
increase higher temperature
(b)
decrease higher temperature
(c)
increase lower temperature
(d)
decrease lower temperature
(e)
keep lower temperature constant. Ans: d
89.Entropy change
depends on
(a)heat
transfer
(b)mass
transfer
(c)change
of temperature
(d)thermodynamic
state
(e)change
of pressure and volume. Ans: a
90.For reversible
adiabatic process, change in entropy is
(a)
maximum
(b)
minimum
(c)
zero
(d)
unpredictable
(e)
negative. Ans: c
91.Isochoric process
is one in which
(a)free
expansion takes place
(b)very
little mechanical work is done by the system
(c)no
mechanical work is done by the system
(d)all
parameters remain constant
(e)mass and energy
transfer do not take place. Ans: c
92. According to first law of thermodynamics
(a) work done by a
system is equal to heat transferred by the system
(b) total internal
energy of a system during a process remains constant
(c)internal
energy, enthalpy and entropy during a process remain constant
(d)total
energy of a system remains constant
(e)entropy
of a system remains constant.
Ans: d
93.Energy can neither
be created nor destroyed but can be converted from one form to other is
inferred from
(a)
zeroth low of thermodynamic
(b)
first law of thermodynamics
(c)
second law to thermodynamics
(d)
basic law of thermodynamics
(e)
claussius statement. Ans: b
94.First law of
thermodynamics furnishes the relationship between
(a)heat
and work
(b)heat,
work and properties of the system
(c)various
properties of the system
(d)various
thermodynamic processes
(e)heat
and internal energy.
Ans: b
95.Change in enthalpy
in a closed system is equal to heat transferred if the reversible process takes
place at constant
(a)
pressure
(b)
temperature
(c)
volume
(d)
internal energy
(e)
entropy. Ans: a
96.In an isothermal
process, the internal energy
(a)increases
(b)decreases
(c)remains
constant
(d)first
increases and then decreases
(e)first
decreases and then increases. Ans: c
97. Change in internal energy in a closed
system is equal to heat transferred if the reversible process takes place at
constant
(a)pressure
(b)temperature
(c)volume
(d)internal
energy
(e)entropy.
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Ans: c
98.According to first
law of thermodynamics
(a)
mass and energy are mutually convertible
(b)
Carnot engine is most efficient
(c)
heat and work are mutually convertible
(d)
mass and light are mutually convertible
(e)
heat flows from hot substance to cold substance. Ans: c
99.Total heat of a
substance is also known as
(a)internal
energy
(b)entropy
(c)thermal
capacity
(d)enthalpy
(e)thermal
conductance. Ans: d
100. First law of thermodynamics
(a)enables
to determine change in internal energy of the system
(b)does
not help to predict whether the system will or not undergo a change
(c)does
not enable to determine change in entropy
(d)provides
relationship between heat, work and internal energy
(e)all
of the above.
Ans: e
101.Addition of heat
at constant pressure to a gas results in
(a)
raising its temperature
(b)
raising its pressure
(c)
raising its volume
(d)
raising its temperature and doing external work
(e) doing external
work. Ans: d
102.Carnot cycle has
maximum efficiency for
(a)reversible
engine
(b)irreversible
engine
(c)new
engine
(d)petrol
engine
(e)diesel
engine. Ans: a
103.Measurement of
temperature is based on
(a)
thermodynamic properties
(b)
zeroth law of thermodynamics
(c)
first law of thermodynamics
(d)
second law of thermodynamics
(e)
joule's law. Ans: b
104.Carnot cycle
efficiency depends upon
(a)properties
of the medium/substance used
(b)condition
of engine
(c)working
condition
(d)temperature
range of operation
(e)effectiveness
of insulating material around the engine. Ans: d
105.Carnot cycle efficiency is maximum when
(a) initial temperature is 0°K
(c) difference between initial and final
temperature is 0°K
(d)
final temperature is 0°C
(e)
initial temperature is minimum possible. Ans: b
106.An engine operates
between temperatures of 900°Kandr2 and another engine between T2 and 400°K For
both to do equal work, value of T2 will be
(a)
650°K
(b)
600°K
(c)
625°K
(d)
700°K
(e)
750°K. Ans: a
107.If heat be
exchanged in a reversible manner, which of the following property of the
working substance will change accordingly
(a) temperature
(b)
enthalpy
(c)
internal energy
(d)
entropy
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(e) all of the above. Ans: d
108.If a system after
undergoing a series of processes, returns to the initial state then
(a)
process is thermodynamically in equilibrium
(b)
process is executed in closed system cycle
(c)
its entropy will change due to irreversibility
(d)
sum of heat and work transfer will be zero
(e)
no work will be done by the system. Ans: d
109.Which of the
following represents the perpetual motion of the first kind
(a)engine
with 100% thermal efficiency
(b)a
fully reversible engine
(c)transfer
of heat energy from low temperature source to high temperature source
(d)a
machine that continuously creates its own energy
(e)production
of energy by temperature differential in sea water at different levels. Ans:
110. An actual engine is to be designed having
same efficiency as the Carnot cycle. Such a proposition is
(a)feasible
(b)impossible
(c)possible
(d)possible,
but with lot of sophistications
(e)desirable.
Ans: d
112.A manufacturer
claims to have a heat engine capable of developing 20 h.p. by receiving heat
input of 400 kcal/mt and working between the temperature limits of 227° C and
27° C. His claim is
(a)
justified
(b)
not possible
(c) may be possible
with lot of sophistications
(d)
cost will be very high
(e)
theroretically possible. Ans: b
113.In a Carnot cycle,
heat is transferred at
(a)constant
pressure
(b)constant
volume
(c)constant
temperature
(d)constant
enthaply
(e)any
one of the above. Ans: c
114.A diathermic wall
is one which
(a)
prevents thermal interaction
(b)
permits thermal interaction
(c)
encourages thermal interaction
(d)
discourages thermal interaction
(e)
does not exist. Ans: b
115.An adiabatic wall
is one which
(a)
prevents thermal interaction
(b)
permits thermal interaction
(c)
encourages thermal interaction
(d)
discourages thermal interaction
(e)
dos not exist. Ans: a
116.The door of a
running refrigerator inside a room was left open. Which of the following
statements is correct?
(a)
The room will be cooled to the temperature inside the refrigerator.
(b)
The room will be cooled very slightly.
(c)
The room will be gradually warmed up.
(d)
The temperature of the air in room will remain unaffected.
(e)
any one of above is possible depending on the capacity. Ans: c
117.Compressed air
coming out from a punctured football
(a)becomes
hotter
(b)becomes
cooler1
(c)remains
at the same temperature
(d)may
become hotter or cooler depending upon the humidity of the surround¬ing air
(e)attains
atmospheric temperature.
Ans: b
118. Water contained in a beaker can be made
to boil by passing steam through it
(a)at
atmospheric pressure
(b)at a pressure below
the firuosphejric pressure
(c)at
a pressure greater than atmospheric pressure
(d)any
pressure
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(e) not possible. Ans: c
119. During throttling process
(a)heat
exchange does not take place
(b)no
work is done by expanding steam
(c)there
is no change of internal energy of steam
(d)all
of the above
(e)entropy
decreases.
Ans: d
120.The energy of
molecular motion appears as
(a)
heat
(b)
potential energy
(c)
surface tension
(d)
friction
(e)
increase in pressure. Ans: a
121.A sudden fall in
the barometer reading is a sign of approaching
(a)
fine weather
(b)
rains
(c)
storm
(d)
cold wave
(e)
hot wave. Ans: c
122.The unit'of
universal gas constant is
(a)watts/°K
(b)dynes/°C
(c)ergscm/°K
(d)erg/°K
(e)none
of the above. Ans: d
123.Calorie is a
measure of
(a)
specific heat
(b)
quantity of heat
(c)
thermal capacity (d)entropy
(e)
work. Ans: b
124.I kgf/cm2 is equal
to
(a)
760 mm Hg
(b)
zero mm Hg
(c)
735.6 mm Hg
(d)
1 mm Hg
(e)
lOOmmHg. Ans: c
125.Barometric
pressure is equal to
(a)
760 mm Hg
(b)
zero mm Hg
(c)
735.6 mm Hg
(d)
1 mm Hg
(e)
100mm Hg. Ans: a
126.One barometric
pressure or 1 atmospheric pressure is equal to
(a)
1 kgf/cnr2
(b)
1.033 kgf/cm2
(c)
0 kgf/cm2
(d)
1.0197 kgf/cm2
(e)
100 kgf/cm2. Ans: b
127.The first law of
thermodynamics is the law of
(a)conservation
of mass
(b)conservation
of energy
(c)conservation
of momentum
(d)conservation
of heat
(e)conservation
of temperature. Ans: b
128. A perpetual motion machine is
(a)a
thermodynamic machine
(b)a nonthermodynamic
machine
(c)a
hypothetical machine
(d)a
hypothetical machine whose operation would violate the laws of thermodynamics
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(e) an inefficient machine. Ans: d
129.Kelvin Planck's
law deals with
(a)
conservation of heat
(b)
conservation of work
(c)
conversion of heat into work
(d)
conversion fo work into heat
(e)
conservation of mass. Ans: c
130.According to
Clausis statement of second law of thermodynamics
(a)heat
can't be transferred from low temperature source to high temperature source
(b)heat
can be transferred for low temperature to high temperature source by using
refrigeration cycle.
(c)heat
can be transferred from low temperature to high temperature source if COP of
process is more than unity
(d)heat
can't be transferred from low temperature to high temperature source without
the aid of external energy
(e)all
of the above.
Ans: d
131.Thermal power
plant works on
(a)
Carnot cycle
(b)
Joule cycle
(d)
Rankine cycle
(d)
Otto cycle
(e)
Brayton cycle. Ans: c
132.Which of the following
is an irreversible cycle
(a)
carnot
(b)
Stirling
(c)
ericsson
(d)
all of the above
(e) none of the above.
Ans: e
133.Otto cycle
consists of following four processes
(a)
two isothermals and two isentropics
(b)
two isentropics and two constant volumes
(c)
two isentropics, one constant volume and one constant pressure
(d)
two isentropics and two constant pressures
(e)
none of the above. Ans: b
134.The efficiency of
a Carnot engine depends on
(a)working
substance
(b)design
of engine
(c)size
of engine
(d)type
of fuel fired
(e)temperatures
of source and sink. Ans: e
135.For same
compression ratio and for same heat added
(a)
Otto cycle is more efficient than Diesel cycle
(b)
Diesel cycle is more efficient than Otto cycle
(c)
efficiency depends on other factors
(d)
both Otto and Diesel cycles are equally efficient
(e)
none of the above. Ans: a
136.The efficiency of
Carnot cycle is maximum for
(a)gas
engine
(b)well
lubricated engine
(c)petrol
engine
(d)steam
engine
(e)reversible
engine. Ans: e
137. Carnot cycle is
(a) a reversible cycle
(ft) an irreversible cycle
(c)a
semireversible cycle
(d)a
quasi static cycle
(e)an
adiabatic irreversible cycle. Ans: a
138. Diesel cycle consists of following four
processes
(a)two
isothermals and two isentropics
(b)two
isentropics, and two constant volumes.
(c)two
isentropics, one constant volume and one constant pressure
(d)two isentropics and
two constant pressures
(e)none
of the above.
Ans: c
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139. If both Stirling
and Carnot cycles operate within the same temperature limits, then efficiency
of Stirling cycle as compared to Carnot cycle
(a)more
(b)less
(c)equal
(d)depends
on other factors
(e)none
of the above.
Ans: c
140.Stirling and
Ericsson cycles are
(a)
reversible cycles
(b)
irreversible cycles
(c)
quasistatic cycles
(d)
semireversible cycles
(e)
adiabatic irreversible cycles. Ans: a
141.A cycle consisting
of two adiabatics and two constant pressure processes is known as
(a)
Otto cycle
(b)
Ericsson cycle
(c)
Joule cycle
(d)
Stirling cycle
(e)
Atkinson cycle. Ans: c
142.Reversed joule
cycle is called
(a)Carnot
cycle
(b)Rankine
cycle
(c)Brayton
cycle
(d)Bell
Coleman cycle
(e)Dual
cycle.
Ans: c
143. Brayton cycle consists' of following four
processes
(a) two isothermals
and two isentropics
(b) two isentropics
and two constant volumes
(c)two
isentropics, one constant volume and one constant pressure
(d)two
isentropics and two constant pressures
(e)none
of the above.
Ans: d
144.Which of the
following cycles is not a reversible cycle
(a)
Carnot
(b)
Ericsson
(c)
Stirling
(d)
Joule
(e)
none of the above. Ans: e
145.The cycle in which
heat is supplied at constant volume and rejected at constant pressure is known
as
(a)
Dual combustion cycle
(b)
Diesel cycle
(c)
Atkinson cycle
(d)
Rankine cycle
(e)
Stirling cycle. Ans: c
146.The efficiency of
Diesei cycle with decrease in cut off
(a)increases
(b)decreases
(c)remains
unaffected
(d)first
increases and then decreases
(e)first
decreases and then increases. Ans: a
147.Which of the
following cycles has maximum efficiency
(a)
Rankine
(b)
Stirling
(c)
Carnot
(d)
Brayton
(e)
Joule. Ans: c
148.The ideal
efficiency of a Brayton cycle without regeneration with increase ni pressure
ratio will
(a)
increase
(b)
decrease
(c)
remain unchanged
(d) increase/decrease
depending on application
(e)
unpredictable. Ans: a
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149.The
ideal efficiency of a Brayton cycle with regeneration, with increase in
pressure ratio will
(a)
increase
(b)
decrease
(c)
remain unchanged
(d)
increase/decrease depending on application
(e)
unpredictable. " Ans: b
150.The following
cycle is used for air craft refrigeration
(a)Brayton
cycle
(b)Joule
cycle
(c)Carnot
cycle
(d)BellColeman
cycle
(e)ReversedBrayton
cycle. Ans: e
151. Gas turbine cycle consists of
(a)two
isothermals and two isentropics
(b)two
isentropics and two constant volumes
(c)two
isentropics, one constant volume and one constant pressure
(d)two
isentropics and two constant pressures
(e)none
of the above.
Ans: d
152. The thermodynamic difference between a
Rankine cycle working with saturated steam and the Carnot cycle is that
(a)carnot
cycle can't work with saturated steam
(b)heat
is supplied to water at temperature below the maximum temperature of the cycle
(c)a
rankine cycle receives heat at two places
(d)rankine
cycle is hypothetical
(e)none
of the above.
Ans: b
