Previous year question papers

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1. Which of the following laws is applicable for
the behaviour of a perfect gas?
A. Boyle’s law
B. Charle’s law
C. Gay-Lussac law
D. All options are correct
Ans. D
Sol: perfect gas follow
PV = nRT
Which is come from-
Boyle’s law-P ∝
1
V
, or P1V1 = P2V2
The volume of a given mass of a gas is
inversely related to the pressure exerted on
it at a given temperature and given number
of moles.
• Charle’s lawV ∝ T , or V1/T1 = V2/T2
The volume (V) of a given mass of a gas, at
constant pressure (Pa), is directly
proportional to its temperature (K).
• Gay-Lussac law-P ∝ T, or P1/T1 = P2/T2
For a given mass and constant volume of an
ideal gas, the pressure exerted on the sides
of its container is directly proportional to its
absolute temperature.
2. According to Dalton’s law, the total pressure
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
Ans. C
Sol: In a mixture of non-reacting gases, the total
pressure exerted is equal to the sum of the
partial pressures of the individual gases.
Ptotal = ∑ × Pn
i=1 i or
Ptotal = P1 + P2 + ………..+ Pn
Where P1, P2, P3, ….. Pn represent the partial
pressures of each component
Pi = PtotalYi
Yi is mole fraction of single gas in mixture of
gases
3. 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
Ans. A
Sol: closed heat exchanger is suitable example of
closed system.
4. Kinetic theory of gases assumes that the
collisions between the molecules are ____.
A. perfectly elastic B. perfectly inelastic
C. partly elastic D. partly inelastic
Ans. A
Sol: Perfectly elastic collisions is define as there
is no loss of kinetic energy during collisions.
Perfectly elastic collisions occur only if some
part of kinetic energy will not change into
other forms like heat or noise.
5. Superheated vapour behaves _________.
A. exactly as gas
B. as steam
C. as ordinary vapor
D. approximately as gas
Ans. D
Sol: A gas refers to a substance that has a single
defined thermodynamic state at room
temperature whereas a vapor refers to a
substance that is a mixture of two phases at
room temperature, namely gaseous and
liquid phase. But when temperature of
vapour increase than gaseous properties in
vapour increase. Like motion of molecule.
6. 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
Ans. A
Sol: P ∝ T , or P = kT
If P = 0, than T = 0K , or T = -273.16 ℃
7. 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
Ans. C
Sol: boiler is a example of open system in which
heat mass both will cross the boundary

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8. Charge in enthalpy of a system is the heat
supplied at
A. constant pressure
B. constant temperature
C. constant volume
D. constant entropy
Ans. A
Sol: heat supplied to the system at atmospheric
pressure is consider as enthalpy because
pressure is 1atm.
9. 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
Ans. A
Sol:
10. When a gas flows through a very long pipe of
uniform cross section, the flow
approximately
A. isentropic B. isobaric
C. isothermal D. adiabatic
Ans. C
Sol: Isothermal flow is a model of compressible
fluid flow whereby the flow remains at the
same temperature while flowing in a conduit.
In the model, heat transferred through the
walls of the conduit is offset by frictional
heating back into the flow.
11. When a liquid boils at constant pressure, the
following parameter increases
A. temperature
B. heat of vaporization
C. kinetic energy
D. entropy
Ans. D
Sol: during boiling of liquid, randomness of
molecule increases hence entropy increase
12. 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. All of these
Ans. D
Sol: → enables to determine change in internal
energy of the system
∆U = Q – W
→ does not help to predict whether the
system will or not undergo a change
means it does not give any information
about spontaneity and the direction of the
process.
→ first law of thermodynamics not give any
idea about entropy
13. Carnot cycle efficiency depends upon ___.
A. properties of the medium/substance used
B. condition of engine
C. working condition
D. temperature range of operation
Ans. D
Sol: η = 1 -
Tc
Th
Where Tc is the absolute temperature of cold
reservoir, Th TC is the absolute temperature
of hot reservoir
If temperature of cold reservoir decrease than
efficiency will increase
Or, if temperature of hot reservoir increase
than efficiency will increase
14. Steam flow through a nozzle is considered as
__________.
A. constant flow
B. isothermal flow
C. adiabatic flow
D. constant volume flow
Ans. C
Sol: It is assumption in which, when heat energy
convert into kinetic energy through nozzle
than there is no loss of heat energy during
energy conversion from flow through a
nozzle
15. A sudden fall in the barometer reading is a
sign of approaching _________.
A. fine weather B. rains
C. storm D. cold wave
Ans. C
Sol: falling of barometer reading show that air
pressure is low
And wind flow from higher pressure to lower
pressure and storm is a violent disturbance of
the atmosphere with strong winds

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16. It is proposed to make a direct heat-to-work
converter out of an elementary system which
absorbs heat while doing isothermal work
exactly equal to the heat absorbed, thereby
keeping internal energy constant. Such a
system is
A. not possible B. possible
C. not desirable D. commendable
Ans. A
Sol: according to question
Work = Qabsorb – Qrej. and
Qrej. = 0
Work = Qabsorb
means heat rejection is zero or efficiency of
heat engine is one which is not possible and
contradict second law of thermodynamics
17. Stirling and Ericsson cycles are
A. reversible cycle
B. irreversible cycle
C. quasi-static cycles
D. semi-reversible cycles
Ans. A
Sol: Stirling cycle has two constant volume and
two constant temperature processes. This
cycle resembles the Carnot cycle where the
Ericsson cycle contains two constant volume
processes instead of two isentropic processes
in the Carnot cycle.
Efficiency of both cycle is same and is equal
to carnot cycle.
18. Ericsson cycle consists of the following four
processes
A. two isothermals and two isentropics
B. two isothermals and two constant
volumes
C. two isothermals and two constant
pressures
D. two adiabatics and two constant pressures
Ans. C
Sol: Process 2→3 Isothermal compression
Process 3→4 Isobaric heat addition
Process 4→1 Isothermal expansion
Process 1→2 Isobaric heat removal
19. A petrol engine theoretically operates on
A. constant pressure cycle
B. constant volume cycle
C. constant temperature cycle
D. constant entropy cycle
Ans. B
Sol: In theoretical petrol engine heat addition
occur at constant volume
20. Two balls of same material and finish have
their diameters in the ratio of 2:1 and both are
heated to same temperature and allowed to
cool by radiation. Rate of cooling by big ball
as compared to smaller one will be in the
ratio of
A. 1:1 B. 2:1
C. 1:2 D. 4:1
Ans. C
Sol: r1/r2 = 2/1
Density of both ball are same
M1/volume1
= M2/volume2 M1/
4
3
π(2r2)3
= M2/
4
3
π(r2)3
M1 = 8M2
dT
dt
=
𝜎𝐴
𝑚Cp
T4
(
dT
dt
)1/(
dT
dt
)2 = (
𝜎𝐴
𝑚Cp
T4
)1/(
𝜎𝐴
𝑚Cp
T4
)2
= m2A1/m1A2
= m24π(2r2)2
/8m24π(r2)2
(
dT
dt
)1/(
dT
dt
)2 = 1/2
21. A ideal gas at 27°C is heated at constant
pressure till its volume becomes three times.
The temperature of gas then will be
A. 81°C B. 900°C
C. 627°C D. 927°C
Ans. C
Sol: PV = nRT
P1 = P2 and V2 = 3V1
nRT1/V1 = nRT2/V2
300/V1 = T2/3V1
T2 = 900K , or
T2 = 627℃

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22. When two gases suddenly mix up with each
other then resultant entropy of the system
will
A. decrease
B. increase
C. remain same
D. may increase or decrease depending upon
the initial conditions of the gases
Ans. B
Sol: entropy is always increases. resultant entropy
of the system is the sum of the entropies of
the two gases before mixing.
23. Which of the following is not an extensive
property
A. entropy B. enthalpy
C. internal energy D. density
Ans. D
Sol: Extensive property depend on the system size
or the amount of material in the system.
Entropy, Enthalpy, Internal energy increase
with increase mass of the system but we
cannot say that density will increase with
increase with mass and density is intensive
property.
24. Element is defined as the _________.
A. substance which cannot be resolved into
simpler form
B. element made up of minute and
chemically indivisible particles
C. smallest quantity of a substance which
can exist by itself in chemically recognized
form
D. smallest known particle
Ans. A
Sol: Element is a substance that cannot be broken
down into simpler components by any non-
nuclear chemical reaction. An element is
uniquely determined by the number of
protons in the nuclei of its atoms. The
number of protons in the nucleus of the atom
of an element is known as the atomic number
of that element. The number of electrons in
the atom of a specific element can vary
25. The process of sublimation is found to occur
in the case of
A. liquid nitrogen B. solid CO2
C. solid O2 D. steel
Ans. B
Sol: conditions necessary for sublimation-
• The pressure needs to be lower than the
pressure of the triple point
• The substance must be present in its solid
state
• The temperature must rise high enough to
produce a gas
Surface temperature of dry ice is -78.5℃ and
triple point pressure is 5.2 atm
While at atmospheric condition temperature
is 30℃ and pressure is 1 atm
26. Thermal conductivity of non-metal
amorphous solids with decrease in
temperature _________.
A. increases
B. decreases
C. remains constant
D. may increase or decrease depending on
temperature
Ans. B
Sol: movement of particle in amorphous solid
increase with increase temperature.
Therefore thermal conductivity is also
increase with increase temperature and vise-
versa.
27. Heat transfer in liquid and gases take place
by _____.
A. conduction
B. convection
C. radiation
D. conduction and convection both
Ans. B
Sol: the movement caused within a fluid by the
tendency of hotter and therefore less dense
material to rise, and colder, denser material
to sink under the influence of gravity, which
consequently results in transfer of heat. In
convection molecule is move instead of
vibration in conduction.
28. Temperature of steam at round 540°C can be
measure by __________.
A. thermometer
B. radiation-pyrometer
C. thermistor
D. thermocouple
Ans. D
Sol: A thermocouple is an electrical device
consisting of two dissimilar electrical
conductors forming electrical junctions at
differing temperatures. A thermocouple
produces a temperature-dependent voltage as
a result of the thermoelectric effect, and this
voltage can be interpreted to measure
temperature.

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29. The amount of heat flow through a body by
conduction is ______.
A. directly proportional to the surface area of
the body
B. directly proportional to the temperature
difference on the two faces of the body
C. dependent upon the material of the body
D. All options are correct
Ans. D
Sol: Q/t = KA (T2 – T1)/d
Q/t = amount of heat flow
A = area
d = distance between two area
T2 and T1 temperature of two surface
K depend upon meterial
30. Unit of thermal diffusivity is
A. m2
/hr B. m2
/hr°C
C. kcal/m2
hr D. kcal/m.hr
Ans. A
Sol: thermal diffusivity is the thermal
conductivity divided by density and specific
heat capacity at constant pressure.
Thermal conductivity/ density and specific
heat capacity
= (J/hr×m× 𝐾)/(kg/m3
)(J/kg× 𝑘)
= m2
/hr
31. For forward inclined vanes i.e., vanes having
exit angle greater than 90°, which of the
following curves holds good?
A. Curve A
B. Curve B
C. Curve C
D. All options are correct
Ans. C
Sol:
32. The property of a fluid which enables it to
resist tensile stress is known as
A. compressibility B. surface tension
C. cohesion D. adhesion
Ans. C
Sol: the intermolecular attraction between like-
molecules.
33. When the flow parameters at any given
instant remain same at every point, then flow
is said to be
A. quasi static B. steady state
C. laminar D. uniform
Ans. D
Sol: uniform flow is define as flow in which at
every cross section area velocity will be
same.
34. An object having 10 kg mass weights 9.81 kg
on a spring balance. The value of ‘g’ at this
place is _______.
A. 10 m/sec2
B. 9.81 m/sec2
C. 10.2 m/sec2
D. 9.75 m/sec2
Ans. A
Sol: in case of spring balance both side value will
be same
Actual mass × gravity=mass by spring × g’
10×9.81 = 9.81× g’
g’
= 10m/sec2
35. The figure below shows four curves A, B, C,
D on a plot of viscous shear stress versus
velocity gradient for three fluids, viz..,
Newtonian, non-Newtonian and ideal; and an
ideal solid. For ideal solid, the curve
applicable is:-
A. A B. B
C. C D. D
Ans. D
Sol: There is no any velocity gradient between the
layer of solid.

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36. The velocity distribution for flow between
two fixed parallel plates _________.
A. is constant over the cross-section
B. is zero at the plates and increases linearly
to the midplane
C. varies parabolically across the section
D. is zero in middle and increases linearly
towards the plates
Ans. C
Sol:
37. Choose the correct relationship
A. specific gravity = gravity x density
B. dynamic viscosity = kinematic viscosity x
density
C. gravity = specific gravity x density
D. kinematic viscosity = dynamic viscosity x
density
Ans. B
Sol: relation between dynamic and kinematic
viscosity is
v=μ/ρ
v is kinematic viscosity
μ is absolute or dynamic viscosity
ρ is density
38. Select the wrong statement
A. Viscosity of a fluid is that property which
determines the amount if its resistance to a
shearing force
B. Viscosity is due primarily to interaction
between fluid molecules
C. Viscosity of liquids decreases with
increase in temperature
D. Viscosity of liquids is appreciably
affected by change in pressure
Ans. D
Sol: the viscosity usually depends on its
composition and temperature. for
compressible fluids, it depends on
temperature and varies very slowly with
pressure.
39. A one dimensional flow is one which ____.
A. is uniform flow
B. is steady uniform flow
C. takes place in straight lines
D. involves zero transverse component of
flow
Ans. D
Sol: One-dimensional flow: All the flow
parameters may be expressed as functions of
time and one space coordinate only. E.g. the
flow in a pipe is considered one-dimensional
when variations of pressure and velocity
occur along the length of the pipe, but any
variation over the cross-section is assumed
negligible.
40. If cohesion between molecules of a fluid is
greater than adhesion between fluid and
glass, then the free level of fluid in a dipped
glass tube will be
A. higher than the surface of liquid
B. the same as the surface of liquid
C. lower than the surface of liquid
D. unpredictable
Ans. C
Sol:
41. Reynolds number is significant in ____.
A. supersonics, as with projectiles and jet
propulsion
B. full immersion or completely enclosed
flow, as with pipes, aircraft wings, nozzles
etc.
C. simultaneous motion through two fluids
where there us a surface of discontinuity,
gravity force, and wave making effects, as
with ship’s hulls.
D. All options are correct
Ans. B
Sol: Option A is significant of Mach number
Option B is significant of Reynolds number
Option C is significant of froude number
42. For pipes, turbulent flow occurs when
Reynolds number is _______.
A. less than 2000
B. between 2000 and 4000
C. more than 4000
D. less than 1000
Ans. C

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Sol: for pipe
Re < 2000 laminar flow
2000 < Re < 4000 transition flow
Re > 4000 turbulent flow
43. Two forces act at an angle of 120°. If the
greater force is 50 N and their resultant is
perpendicular to the smaller force, the
smaller force is _____N
A. 20 B. 25
C. 30 D. 35
Ans. B
Sol:
Fs/sin150 = Fg/sin90
Fs = 25 N
44. In laminar flow through a round tube, the
discharge varies ________.
A. linearly as the viscosity
B. inversely as the pressure drop
C. as the cube of the diameter
D. inversely as the viscosity
Ans. D
Sol: discharge is proportional to velocity and
velocity is decreases with increases with
viscosity means velocity is inversely
proportional to viscosity and also discharge.
45. For frictionless fluid, the contraction
coefficient for Borda’s mouthpiece is
A. 1 B. 0.5
C. 0 D. 0.97
Ans. D
Sol: the contraction coefficient for Borda’s
mouthpiece is depend upon practical
experiment and it is always less than one.
46. Bernoulli’s theorem deals with the
conservation of
A. mass B. force
C. momentum D. energy
Ans. D
Sol: Bernoulli’s theorem is base on conservation
of energy in which if non-compressible and
non-viscous fluid is flowing than sum of
pressure energy , kinetic energy and potential
energy will be constant at any point in the
flow.
47. The motion of a fluid is vortex if each particle
of the fluid moves in a circular path with the
speed which ________.
A. is constant
B. is directly proportional to distance from
center
C. varies as square of distance from center
D. varies inversely as the distance from
center
Ans. D
Sol: 𝜔 = v/r
48. Which of the following represents steady
non-uniform flow?
A. flow through an expanding tube at an
increasing rate
B. flow through an expanding tube at
constant rate
C. flow through a long pipe at decreasing
rate
D. flow through a long pipe at a constant rate
Ans. B
Sol: steady flow is define as flow at any cross
section is constant with respect to time and
non-uniform flow is define as flow which is
vary one cross section to another cross
section.
In statement constant rate and expanding
tube give an idea about steady flow and non-
uniform respectly.
49. If the particles of a fluid attain such velocities
that velocities vary from point to point in
magnitude and direction, as well as from
instant to instant, the flow is said to be
________.
A. disturbed flow B. turbulent flow
C. turbid flow D. non-uniform flow
Ans. B
Sol: flow of a fluid in which its velocity at any
point varies rapidly in an irregular manner.
50. The discharge of broad crested weir is
maximum if the head of water on the
downstream side of weir as compared to the
head on the upstream side of the weir is
_________.
A. one-half B. one-third
C. two-third D. three-fourth
Ans. C

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Sol: formula for discharge of broad crested weir
is-
Q = Cd× 𝐿√2g ×( Hh2
-h3
)0.5
Q is maximum if Hh2
-h3
is maximum
d(Hh2
-h3
)/dh =0
h = (2/3)H
51. Any fluid flow follows _______.
A. Bernoulli’s equation
B. Newton’s law of viscosity
C. Darcy’s equation
D. continuity equation
Ans. D
Sol: → The simple form of Bernoulli's equation is
valid for incompressible flows.
→ Newtonian fluid is a fluid in which the
viscous stresses arising from its flow, at
every point, are linearly proportional to the
local strain rate—the rate of change of its
deformation over time.
→Darcy's law is an equation that describes
the flow of a fluid through a porous medium.
→ continuity equation is applicable for all
type of flow that is product of area and
velocity at any cross section of flow is
constant.
52. A fluid flow taking place continuously round
a curved path about a fixed axis of rotation,
is known as _________.
A. rotational flow B. radial flow
C. circular flow D. vortex flow
Ans. D
Sol:
53. Vertical distribution of velocity in an open
channel for laminar flow can be assumed as
_________.
A. logarithmic
B. parabolic
C. straight line (constant)
D. hyperbolic
Ans. B
Sol:
54. Drag is defined as the force component
exerted on an immersed object, the
component acting in direction is ____.
A. normal to flow direction
B. parallel to flow direction
C. at resultant angle
D. radial to flow direction
Ans. B
Sol: Drag is a force acting opposite to the relative
motion of any object moving with respect to
a surrounding fluid.
55. According to Darcy’s formula, loss of head
due to friction in the pipe is
Where f = Darcy’s coefficient
l = length of pipe
v = velocity of liquid flow
d = diameter of pipe
A. 4flv2
/2gd B. flv2
/gd
C. 2flv2
/gd D. 4flv/gd
Ans. A
Sol: in case of flow through pipe head loss due to
friction is hs
P1/𝜌𝑔 + 𝑉1
2
/2g + Z1 = P2/𝜌𝑔 + 𝑉2
2
/2g + Z2 + hf
And, hf = 4flv2
/2gd
56. Hydraulic gradient is equal to
A. (difference in water surface)/(total length
of channel)
B. (head loss due to friction)/(total length of
channel)
C. (wetted perimeter)/(total length of
channel)
D. (area od cross-section)/(total length of
channel)
Ans. B

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Sol: The hydraulic gradient is a vector
gradient between two or more hydraulic head
measurements over the length of the flow
path.
Hydraulic gradient = dh/dl
= (h2 – h1)/length of channel
h2 and h1 is hydraulic head at two point
57. A liquid jet from a nozzle exposed to
atmosphere traverses along _____.
A. a straight line B. a circular path
C. an elliptical path D. parabolic path
Ans. D
Sol: In this case jet follow projectile motion
which is parabolic.
58. Which of the following represents unsteady
uniform flow ___________.
A. flow through an expanding tube at an
increasing rate
B. flow through an expanding tube at
constant rate
C. flow through a long pipe at decreasing
rate
D. flow through a long pipe at constant rate
Ans. C
Sol: flow through a long pipe at decreasing rate
means velocity at any cross section is
decreases with time.
59. Turbulent flow generally occurs for cases
involving _______.
A. very slow motions
B. very viscous fluids
C. very narrow passages
D. None of the these
Ans. D
Sol: very slow motions, very viscous fluids and
very narrow passages are the case of laminar
flow.
For Turbulent flow high velocity and less
viscous fluid required.
60. Bernoulli’s theorem is applicable for
A. streamline flow
B. steady flow
C. turbulent flow
D. perfect incompressible fluid flowing in
continuous streams
Ans. D
Sol: Bernoulli’s theorem is applicable for ideal
fluid flow. In which non-compressible and
non viscous fluid is used.
61. In the case of an elastic bar fixed at upper and
loaded by a falling weight at lower end, the
shock load produced can be decreased by
A. decreasing the cross-section area of bar
B. increasing the cross-section area of bar
C. remain unaffected with cross-section area
D. would depend upon other factors
Ans. A
Sol: load = weight/ area
Load will be decrease if area increase
62. For a long and narrow cross section (i.e., ratio
of b/t, breadth b and thickness t above 10) bar
subjected to torsion T, the value of maximum
shear stress will be
A. T/bt2
B. T/(4bt2
)
C. 2T/bt2
D. None of these
Ans. D
Sol: 𝜏 = T/z
z is section modulus and z= bt2
/(3+1.8×
𝑡
𝑏
)
z = bt2
/3 (approx. equal)
𝜏 = 3T/bt2
63. Guest’s theory of failure is applicable for
following of materials
A. brittle B. ductile
C. elastic D. plastic
Ans. B
Sol: failure will occur in a material if the
maximum shear stress at a point due to a
given set of load exceeds the maximum shear
stress induced due to a uniaxial load at the
yield point. Yielding is a starting point of
ductility.
64. If a load W is applied instantaneously on a
bar of cross section A, then the stress induced
in the bar in worst case will be
A. W/A
B. W/2A
C. 2W/A
D. (2W/A) x (a factor greater than unity)
Ans. C
Sol: sudden applied force on a body is always
equal to the 2 times of a gradually increases
force of same value.
65. The output of a diesel engine can be
increased without increasing the engine
revolution or size in following way.
A. by feeding more fuel
B. by increasing flywheel size
C. by heating incoming air
D. by supercharging
Ans. D

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Sol: supercharging is a process to increases the
mass of fresh air (or density) in diesel engine
to burn fuel in proper way to produced more
amount of work from same input.
66. Resilience of a bolt may be increased by
A. increasing its length
B. increasing its shank diameter
C. increasing diameter of threaded portion
D. increasing head size
Ans. A
Sol: Resilience is define as strain energy per unit
volume. If length increase compare to
diameter, stress increases therefore resilience
increase.
67. As pump speed increases, its NPSH (net
positive suction head) requirement ____.
A. increases B. decreases
C. remains same D. unpredictable
Ans. A
Sol: NPSH = (ps / ρg + vs
2
/ 2 g ) - pv / ρg
if pump speed increase (vs
2
/ 2 g) term
increases therefore NPSH increases.
68. Wire ropes are used for applications
experiencing ____.
A. low speeds and low tension
B. low speeds and high tension
C. high speeds and low tension
D. high speed and high tension
Ans. B
Sol: low speed due to fatigue and high tension
because elastic limit is more.
69. The part of the tooth between the pitch circle
and dedendum circle is called ____.
A. half tooth B. flank
C. face D. upper tooth
Ans. B
Sol: The part of the tooth between the pitch circle
and dedendum circle is called flank
70. In skew bevel gears, the axes _________.
A. are non-parallel and non-intersecting, and
the teeth are curved
B. are non-parallel and non-intersecting and
teeth are straight
C. intersect, and the teeth are curved and
oblique
D. intersect, and the teeth are curved and can
be ground
Ans. B
Sol:
71. Strain is defined as the ratio of _____.
A. change in volume to original volume
B. change in length to original length
C. change in cross sectional area to original
cross-sectional area
D. All options are correct
Ans. D
Sol: → change in volume to original volume is
called volumetric strain.
→ change in length to original length is
called longitudinal strain.
→ change in cross sectional area to original
cross-sectional area is called lateral strain.
72. The unit of Young’s modulus is ______.
A. mm/mm B. kg/cm
C. kg D. Kg/cm2
Ans. D
Sol: E = stress/strain
Strain is dimensionless and unit of stress is
kilogram-force per square centimetre.
73. The materials having same elastic properties
in all directions are called:-
A. ideal materials
B. uniform materials
C. isotropic material
D. practical materials
Ans. C
Sol: Isotropic Material is defined as if its
mechanical and thermal properties are the
same in all directions.

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74. The ultimate tensile stress of mild steel
compared to ultimate compressive stress is
__________.
A. same
B. more
C. less
D. more or less depending on the other
factors
Ans. B
Sol: ultimate tensile stress of mild steel is of the
order of 840Mpa.
Ultimate compressive stress of mild steel is
of the the order of 180Mpa.
75. The Young’s modulus of a wire is defined as
the stress which will increase the length of
wire compared to its original length:-
A. half B. same amount
C. double D. one-fourth
Ans. B
Sol: same amount because Young’s modulus is
fixed for material.
76. During a tensile test on a specimen of 1 cm2
cross-section, maximum load observed was 8
tonnes and area of cross-section at neck was
0.5 cm2
. Ultimate tensile strength of
specimen is
A. 4 tonnes/cm2
B. 8 tonnes/cm2
C. 16 tonnes/cm2
D. 22 tonnes/cm2
Ans. B
Sol: Ultimate tensile strength is engineering stress
therefore area will be 1cm2
Ultimate tensile strength = 8 tonnes/1cm2
77. Which is the false statement about stress-
strain method?
A. It does not exist
B. It is more sensitive to changes in both
metallurgical and mechanical conditions
C. It gives a more accurate picture of the
ductility
D. It can be correlated with stress-strain
values in other tests like torsion, impact,
combined stress tests etc.,
Ans. A
Sol: Stress–strain analysis is an engineering
discipline that uses many methods to
determine the stresses and strains in materials
and structures subjected to forces.
78. Which of the following materials is most
elastic?
A. rubber B. plastic
C. brass D. steel
Ans. D
Sol: above all option value of elastic limit is more
in steel.
79. The total elongation produced in a bar of
uniform section hanging vertically
downwards due to its own weight is equal to
that produced by a weight
A. of same magnitude as that of bar and
applied at the lower end
B. half the weight of bar applied at the lower
end
C. half of the square of weight of bar applied
at the lower end
D. one-fourth of weight of bar applied at the
lower end
Ans. B
Sol: ∆L = WL/2E
(elongation due to self weight)
80. The property of a material which allows it to
be drawn into a smaller section is called:-
A. plasticity B. ductility
C. elasticity D. malleability
Ans. B
Sol: Ductility is a physical property of a material
associated with the ability to be hammered
thin or stretched into wire without breaking.
81. Joggled welded joints are used ___.
A. where longitudinal shear is present
B. where sever loading is encountered and
the upper surface of both pieces must be in
the same plane
C. to join two pieces of metal in the same
manner as rivet joint metals
D. there is nothing called Jogged welded
joint
Ans. B
Sol: joggled welded joints are similar to butt
joints
82. Plain and butt welds may be used on
materials upto approximately:-
A. 25 mm thick B. 40 mm thick
C. 50 mm thick D. 70 mm thick
Ans. A
Sol: if thickness increase extra support is needed
in case of butt joint.

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83. In arc welding, arc is created between the
electrode and work by:-
A. flow of current
B. voltage
C. material characteristics
D. contact resistance
Ans. D
Sol: if resistance will be less than welding will not
be proper.
84. Plug weld joint is used _________.
A. where longitudinal shear is present
B. where severe loading is encountered and
the upper surfaces of both pieces must be in
the same plane
C. to join two pieces of metal in the same
manner as rivet joint metals
D. there is nothing like plug weld joint
Ans. C
Sol:
85. The type of riveted joint shown in the figure
below is ________.
A. Double riveted lap joint
B. Double riveted butt joint
C. Quadruple riveted lap joint
D. Quadruple riveted butt joint
Ans. B
Soln:
Butt joint The two members to be connected
are placed end to end. Additional plate/plates
provided on either one or both sides, called
cover plates.
If the cover plates are provided on both the
sides of main plates it is called a double cover
butt joint.
86. The main advantage of shell moulding is
that:-
A. a metallic pattern is used
B. the moulds are stronger
C. thin sections can be easily obtained
D. highly complex sections can be easily
obtained
Ans. C
Sol: thin sections can be easily obtained because
there is no need to remove pattern
87. Strength and permeability of served sand are
related to:-
A. grain size B. clay-content
C. hardness D. moisture content
Ans. D
Sol: →strength is increase with moisture content
→ The moulding sand must be sufficiently
porous to allow the dissolved gases, which
are evolved when the metal freezes or
moisture present or generated within the
moulds to be removed freely when the
moulds are poured. This property of sand is
called porosity or permeability.
88. For grinding operation in which heat
generation must be kept minimum, the
following bond of wheel must be used:-
A. resinoid rubber B. silicate
C. vitrified D. shellac
Ans. B
Sol: Silicate bond releases the abrasive grains
more readily than vitrified bond. Silicate
bonded wheels are well suited for grinding
where heat must be kept to a minimum, such
as grinding edged cutting tools. It is not
suited for heavy-duty grinding. Thin cutoff
wheels are sometimes made with a shellac
bond because it provides fast cool cutting
89. The grit size of the abrasives used in the
grinding wheel is usually specified by the:-
A. hardness number
B. size of the wheel
C. softness or hardness of the abrasive
D. mesh number
Ans. D
Sol: Mesh size is the mesh number and its
relationship to the size of the openings in the
mesh and thus the size of particles that can
pass through these openings.
90. Which abrasive particle would you choose
for grinding tungsten carbide tool inserts?
A. silicon carbide
B. aluminium oxide
C. diamond
D. cubic boron carbide
Ans. C
Sol: tools can be nearly as hard as conventional
abrasives, therefore grinding of tools is done
by super abrasives like diamond and CBN

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91. Free acids in diesel oil for diesel engine lead
to __________.
A. production of highly corrosive gases
corroding the cylinder walls and exhaust
system
B. excessive engine wear
C. damaging of both the storage tank and the
engine
D. deposition on engine parts
Ans. C
Sol: free acid is the acidic form of a substance in
which all acidic groups are fully protonated.
92. Secondary forces in reciprocating mass on
engine frame are:-
A. of same frequency as of primary forces
B. twice the frequency as of primary forces
C. four times the frequency as of primary
forces
D. half the frequency as of primary forces
Ans. B
Soln:
primary force: reaches its maximum value
of mrω2
twice per revolution but secondary
force. It reaches its maximum value of mrω2
four times per revolution.
93. Partial balancing in locomotives results in:-
A. hammer blow, variation of tractive effort,
swaying couple
B. least wear
C. most smooth operation
D. better performance of engine
Ans. A
Soln: for partial balancing ,
1:Variation of Tractive force The resultant
unbalanced force due to the cylinders, along
the line of stroke, is known as tractive
force.
2: The couple has swaying effect about a
vertical axis, and tends to sway the engine
alternately in clock wise and anticlockwise
directions. Hence the couple is known as
swaying couple
3: The maximum magnitude of the
unbalanced force along the perpendicular to
the line of stroke is known as Hammer
blow.
94. In hydrostatic bearing, pressure to lubricant
is supplied by:-
A. external source
B. partially external and partially from
rotation of journal
C. not supplied by external source
D. shaft driven pump
Ans. A
Sol: A hydrostatic bearing employs a positive
pressure supply that maintains clearance
between the rotating and stationary elements.
With a hydrostatically-lubricated bearing, the
lubrication is introduced under pressure
between the moving surfaces.
The load support is a function of the pressure
drop across the bearing and the area of fluid
pressure action.
95. Purpose of using differential gear in
automobile is to:-
A. control speed
B. avoid jerks
C. help in turning
D. obtain rear movement
Ans. C
Sol: Differential gear provide different speed on
both wheel at time of turning.
96. In the figure given below a weight of 20 kg
is suspended at one end of cord and a weight
of 30 kg is suspended at other end of cord
passing over a pulley. Neglecting the weight
of rope and pulley, tension in cord will be:-
A. 30 N B. 20 N
C. 10 N D. None of these
Ans. D
Sol: for 30 kg
ma = mg – T
30a = 294.3 – T -A
for 20 kg
20a = T – 196.2
T = 20a + 196.2
Put in equation A
50a = 294.3 – 196.2
a = 1.962 put in equation A
T = 235.44 N

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97. Isothermal compression though most
efficient, but is not practicable because
A. it requires a 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
Ans. D
Sol: Isothermal compression is a reversible
processes.
98. A body weighing 1000 kg falls 8 cm and
strikes a 500 kg/cm spring. The
deformation of spring will be ____cm.
A. 8 B. 4
C. 16 D. 2
Ans. A
Sol: Potential energy of weight is equal to
spring energy after strike
mgh =
1
2
Kx2
1000×980×(8+x) =
1
2
×(500×980)x2
4(8+x) = x2
x2
– 4x – 32 = 0
x = 8cm
99. Which of the following is the unit of
energy?
A. Joule B. N-m
C. Electron volt D. All of these
Ans. D
Sol: 1N-m = Joule
1eV = 1.6×10-19
Joule
100. When a body slides down an inclined
surface, the acceleration (f) of the body is
given by:-
A. f = g B. f = g sin 𝜃
C. f = g cos 𝜃 D. f = g tan 𝜃
Ans. B
Sol: