SSC-JE Mechanical (2016) SET-1-watermark.pdf-99

www.gradeup.co

1. The ___________ is a dimensionless quantity used 5. In regarding nucleate boiling __________.
Ans. in heat transfer calculations. A. The temperature of the surface is greater than
Sol: Ans. the saturation temperature of the liquid
A. Grashoff number B. Biot number Sol: B. Bubbles are created by expansion of entrapped
2. C. Stanton number D. Prandtl number 6. gas or vapour at small cavities in the surface
C. The temperature is greater than that of film
Ans. B Ans. boiling
Sol: simple index of the ratio of the heat transfer Sol: D. All options are correct
resistances inside of and at the surface of a body. C
Nucleate boiling is a type of boiling that takes place
Biot number is defined as- when the surface temperature is hotter than the
Bi = Lc×h saturated fluid temperature by a certain amount
but where the heat flux is below the critical heat
K flux.
Boundary layer is defined as __________.
h = film coefficient or heat transfer coefficient or A. A thin layer at the surface where gradients of
convective heat transfer coefficient both velocity and temperature are small
B. A thin layer at the surface where velocity and
Lc = characteristic length, which is commonly velocity gradients are large
defined as the volume of the body divided by the C. A thick layer at the surface where velocity and
surface area of the body temperature gradients are large
K = thermal conductivity of the body D. A thin layer at the surface where gradients of
both velocity and temperature are large
An ideal air compressor cycle (with clearance) on D
p-v diagram can be represented by ____
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
B

3. In a shell and tube heat exchanger, baffles are

Ans. provided on the shell side to ________.
Sol:
4. A. Prevent the stagnation of shell side fluid 7. Two insulating materials of thermal conductivity K

Ans. B. Improve heat transfer Ans. and 2K are available for lagging a pipe carrying a
Sol. Sol:
C. Provide support for tubes hot fluid. If the radial thickness of each material is

D. All options are correct the same _________.

D A. Material with higher thermal conductivity

Baffles are an integral part of the shell and tube should be sued for the inner layer and one with

heat exchanger design. A baffle is designed to layer and one with lower thermal conductivity for

support tube bundles and direct the flow the outer

of fluids for maximum efficiency. B. Material with lower thermal conductivity should

The ratio of the thickness of thermal boundary be used for the inner layer and one with higher

layer to the thickness of hydrodynamic boundary thermal conductivity for the outer

layer is equal to (Prandtl number)n, where n is C. It is immaterial in which sequence the

________. insulating materials are used

A. -1/3 B. -2/3 D. None of these

C. 1 D. -1 B

Critical thickness of insulation for Ist and IInd

A Material =

Dt - thermal boundary layer (rc1)  k , (rc )  2k
h h
D – Hydrodynamic boundary layer 2 Hence rc2=2rc1
−1
= ( ) 3

1|Page

www.gradeup.co

so the first material should be used inside and 14. If thermal conductivity of a material of wall varies
second material should be use outside because it Ans. as K_0 (1 + t), then the temperature at the
centre of the wall as compared to that in case of
has higher critical radius constant thermal conductivity, will be __________.

8. Critical thickness of insulation for spheres is given

Ans. by ______. A. More B. Less
Sol:
9. A. k/h B. k/4h C. Same D. Depend on other factors
Ans.
Sol: C. h/2k D. 2k/h A
D
10. It is no longer the case when the thermal
2k/h where k is the thermal conductivity of the conductivity changes with the temperature.
Ans.
Sol: insulation and h is the convection heat transfer
11.
coefficient on the outer surface.
Ans.
Sol: Which surface will have the least emissivity?

12. A. Smooth glass B. Plaster
Ans.
Sol: C. Aluminum foil D. Concrete

13. C

Ans. Emissivity is a measure of a material’s radiating
Sol: efficiency. An emissivity of 1.00 implies that the

material is 100% efficient at radiating energy. An

emissivity of 0.20 implies that the material radiates
only 20% of that which it is capable of radiating.

The process of heat transfer from one particle of

the body to another without the actual motion of

the particle, is known as _________.

A. Conduction B. Convection

C. Radiation D. All options are correct

A

Process of heat transfer from one molecule of the

body to another molecule without the motion of 15. With increase in temperature, thermal conductivity
Particle. Ans. of air _________.
Sol:
The process of heat transfer from a hot body to a A. Increases B. Decreases
16.
cold body is straight line, without affecting the Ans. C. Remains the same D. None of these
Sol:
intervening medium, is known as ________. A
17.
A. Conduction B. Convection Ans. As the temperature of air increases average kinetic
Sol: energy of the molecules increases, thus the
C. Radiation D. All options are correct average speed of molecules increases, thus the
collision rate of the molecules increases. In air the
C thermal (kinetic energy of molecules) energy
between the molecules is transported when they
Heat is carried through the atomic vibration & collide. So if the collision rate is more the rate of
transportation of thermal energy between the
electron motion. molecules is more. Thus the conductivity of air
increases with temperature.
Electromagnetic waves propagate rectilinearly, like

light.

Heat is transferred from an electric bulb by _____.

A. Conduction B. Convection

C. Radiation D. All options are correct

C Liquid metal having highest thermal conductivity is
of _________.
(i) filament is heated due to conduction

(ii) Then there’s convection, which drives a flow A. Sodium B. Potassium

inside the bulb transferring the heat from the C. Lead D. Mercury

filament throughout the bulb via the movement of A

fluids (in this case that’s argon gas). The most widespread liquid metals used in
engineering are alkali metals. Among them sodium
(iii) but finally in last, heat is transferred from an is first and foremost, used as a coolant of fast
reactors and a working fluid of high-temperature
electric bulb by radiation. heat pipes.

Assumption made in the Fourier’s law is that the

heat flow

A. Is in steady state Minimum thermal diffusivity is of ___________.

B. Though a solid medium in one dimension A. Aluminum B. Rubber

A. Only (A) B. Only (B) C. Iron D. Lead

C. Both (A) and (B) D. None of these B

C thermal diffusivity ∝ thermal conductivity

the time rate of heat transfer through a material Above this option thermal conductivity is low for
rubber, so thermal diffusivity will also be low.
is proportional to the negative gradient in the

temperature and to the area, at right angles to that

gradient, through which the heat flows

2|Page

www.gradeup.co

18. Critical radius of a hollow cylinder is defined as

Ans. ________.

19. A. Outer radius which gives maximum heat flow

Ans. B. Outer radius which gives minimum heat flow
Sol:
C. Inner radius which gives minimum heat flow
20.
Ans. D. Inner radius which gives maximum heat flow
Sol:
21. A

Ans. Critical radius of insulation depends on the thermal
Sol:
22. conductivity of the insulation k and the external

Ans. convection heat transfer coefficient h . The rate of
Sol:
heat transfer from the cylinder increases with the

addition of insulation for r2< rcr, reaches a 23. According to Kelvin-Plank’s statement, a perpetual

maximum when r2= rcr, and starts to decrease Ans. motion machine of ______.
for r2> rcr. Thus, insulating the pipe may actually Sol:
increase the rate of heat transfer from the pipe A. First kind is possible
24.
B. First kind is impossible
Ans.
instead of decreasing it when r2< rcr Sol: C. Second kind is impossible
Heat exchangers are used in 25.
D. Second kind is possible
Ans.
A. Condensers and boilers in steam plants Sol: C
26.
B. Radiators Perpetual motion machines of the second
Ans.
C. Intercoolers and preheaters Sol: kind violate the Second Law of Thermodynamics.
27.
D. Condensers and evaporators in refrigerators They convert thermal energy directly
Ans.
and air conditioners into mechanical work, with no exhaust heat being

A. Only A B. Only B emitted; this violates the rule of the production of

C. Only C D. A, B, C and D entropy that entropy in a system must always

D increase.

A heat exchanger is a device used to transfer heat According to kinetic theory of gases, at absolute

between a solid object and a fluid, or between two zero ___________.

or more fluids. The fluids may be separated by a A. Specific heat of molecules reduces to zero

solid wall to prevent mixing or they may be in B. Kinetic energy of molecules reduces to zero

direct contact. C. Volume of gas reduce to zero

Automobile radiator is a heat exchanger of D. Pressure of gas reduce to zero

________ type. B

A. Counter flow B. Parallel flow Absolute zero is the point where where all

C. Cross flow D. Regenerator molecules have no kinetic energy. It is a theoretical

C value (it has never been reached).

A tube bundle carries a heating or cooling fluid According to Gay-Lussac’s law for perfect gases,

(either gas or liquid), normally perpendicular to a the absolute pressure of given mass varies directly

gas flow which passes over the tubes and allows as ___________.

heat to be transferred between the fluids. A. Temperature

For a closed system, difference between the heat B. Absolute temperature

added to the system and work done by the gas, is C. Absolute temperature, if volume remains

equal to the change in ___________. constant

A. Enthalpy B. Entropy D. Product of absolute temperature and volume

C. Internal energy D. Temperature C

C P ∝ T, or

Q = ∆U + W P/T ∝ k, or

Or, ∆U = Q - W P1/T1 = P2/T2

The sequence of process that eventually returns Three states of matter are distinguished with

the working substance to its original state, is respect to molecules by the _________.

known as __________. A. Atoms in molecules

A. Event B. Number

B. Thermodynamic cycle C. Orientation

C. Thermodynamic property D. Character of motion

D. None of these D

B In solids, the particles are tightly packed together

A thermodynamic cycle is a series and and motion is limited to vibration. In liquids,

of thermodynamic processes which returns a the particles have more movement, while in gases,

system to its initial state. Properties depend only they are spread out.

on the thermodynamic state and thus do not Equal volume of all gases, at the same

change over a cycle. Variables such temperature and pressure, contain equal number

as heat and work are not zero over a cycle, but of molecules. This is according to ___________.

rather depend on the process. A. Charle’s law B. Avagardo’s law

C. Joule’s law D. Gay Lussac law

B

3|Page

www.gradeup.co

Sol: Avogadro's law states that the volume occupied by 33. Steady flow occurs when ___________.

28. an ideal gas is directly proportional to the number Ans. A. Pressure does not change along the flow
Ans. Sol:
Sol: of molecules of the gas present in the container. 34. B. Velocity does not change
29.
This gives rise to the molar volume of a gas, which Ans. C. Conditions change gradually with time
Ans. Sol:
Sol: at STP (273.15 K, 1 atm) is about 22.4 L. The D. Conditions do not change with time at any point
35.
30. relation is given by- D
Ans.
Ans. V1/n1 = V2/n2 Sol: steady flow is one in which the conditions (velocity,
Sol: Where V1 and V2 are volume 36.
31. pressure and cross-section) may differ from point
And n1 and n2 are no. of mole Ans.
Ans. Specific heat of a gas, Cp = Cv, at Sol: to point but DO NOT change with time.
Sol:
32. A. Absolute zero B. Critical temperature 37. If the particles of a fluid attain such velocities that

Ans. C. Triple point D. All temperature Ans. vary from point to point in magnitude and direction
Sol: Sol:
A 38. as well as from instant, the flow is _______.

Cp – Cv = -T[( )2at con. p/( )at con. pres.] Ans. A. Uniform flow B. Steady flow
Sol:
C. Turbulent flow D. Laminar flow

At absolute temperature (k=0) C

Cp – Cv = 0, or Turbulent flow is a type of fluid (gas or liquid) flow

Cp = Cv in which the fluid undergoes irregular fluctuations,
The specific heat at constant volume of solids
or mixing, in contrast to laminar flow. In turbulent
obeys Debye’s T3 law at _________.
flow the speed of the fluid at a point is
A. High temperatures continuously undergoing changes in both

B. Low temperatures magnitude and direction.

C. High pressures Flow occurring in a pipeline when a valve is being

D. All temperatures opened is _______.

D A. Steady B. Unsteady

It treats the vibrations of the atomic lattice (heat)

as phonons in a box, in contrast to the Einstein C. Laminar D Vortex

model, which treats the solid as many individual, B

non-interacting quantum harmonic oscillators. The flow will be steady after unsteady flow when valve

Debye model correctly predicts the low of pipeline is just open.

temperature dependence of the heat capacity, For measuring flow by Venturimeter, it should be

which is proportional to T3 -the Debye T3 law. installed in _________.

A reversible process _________. A. Vertical line

A. Must pass through a continuous series of B. Horizontal line

equilibrium states C. Inclined line with upward flow

B. Leaves no history of the events in surroundings D. In any direction and in any location

C. Must pass through the same states on the D

reversed path as on the forward path a pressure drop occurs between the entrance and
throat of the venturimeter. This pressure drop is
D. All options are correct

D measured using a differential pressure sensor if

a reversible process is a process whose direction potential head are not considered.

can be "reversed" by inducing infinitesimal changes A streamline is defined as the line __________.

to some property of the system via

its surroundings, with no increase in entropy A. Parallel to central axis flow

In Red Wood Viscometer _____________. B. Parallel to outer surface to pipe

A. Absolute value of viscosity is determined C. Of equal velocity in a flow

B. Part of the head of fluid is utilized in D. Along with the pressure drop is uniform

overcoming friction C

C. Fluid discharges through orifice with negligible A streamline is a line that is tangential to the

velocity instantaneous velocity direction (velocity is a
vector, and it has a magnitude and a direction).
D. Comparison of viscosity is done

A The purpose of surge tank in a pipe line is to

the value of viscosity of the liquid may be obtained _________.

by comparison with value of time for the liquid of A. Smoothen the flow of water

known viscosity. B. Compensate friction losses in pipe

a rotameter is a device used to measure C. Prevent occurrence of hydraulic jump

__________. D. Relieve pressure due to water hammer

A. Velocity of fluid in pipes

B. Velocity of gauges B/D

C. Votex flow A surge tank is a standpipe or storage reservoir at

D. Flow of fluids the downstream end of a closed aqueduct, feeder,

D dam, barrage pipe to absorb sudden rises of
pressure, as well as to quickly provide extra water
Rotameters (variable area meter) is a flow meter

that measures volumetric flow of liquids and gases during a brief drop in pressure.

in volume/sec.

4|Page

www.gradeup.co

39. The resultant upward pressure of a fluid on a Sol: Pressure drag (Form drag) arises due to the shape
floating body is equal to the weight of fluid of the object and depends on the flow separation
Ans. displaced by the body. This definition is according point.
Sol: to ___________. Friction drag arises due to the friction between the
A. Buoyancy fluid and surface of the object the flow is occurring
40. B. Equilibrium of a floating body around.
C. Archimedes’ principle
Ans. D. Bernoulli’s theorem 45. If one of the wall moves in the direction of flow
Sol: A
41. Buoyancy is the phenomena given by Archimedes Ans. with uniform velocity while the other wall is
which says the body experiences the upward force Sol: stationary, then the resulting flow between parallel
Ans. when it is partially or completely immersed in walls is called _________.
Sol: liquid. 46.
42. Buoyancy force = weight of displaced liquid. Ans. A. Plug flow B. Stoke’s flow
A balloon lifting in air follows the ____________. Sol:
Ans. A. Law of gravitation C. Couette flow D. Euler’s flow
Sol: B. Archimedes principle 47.
43. C. Principle of buoyancy A/C
Ans. D. All options are correct Ans.
Sol: D Sol: Couette flow is the flow of a viscous fluid in the
By comparing the weight of the object vs the
44. weight of this displaced volume of gas or liquid, it space between two surfaces, one of which is
can determine the object will float or sink moving tangentially relative to the other. The flow
Ans. Hydraulic grade line as compared to the centre line
of conduct _______. is driven by virtue of viscous drag force acting on
A. Should be always above
B. Should be always below the fluid, but may additionally be motivated by an
C. Should always be parallel applied pressure gradient in the flow direction.
D. May be above or below
A The ratio of the energy absorbed by the body to
The central line of the pipe will give only static
head but hydraulic gradient line will give static total energy falling on it is called _____.
head + pressure head
A Piezometer cannot be used for pressure A. absorptive power B. emissive power
measurement in pipes when ______.
A. Pressure difference is low C. emissivity D. None of these
B. Velocity is high
C. Fluid in the pipe is a gas A
D. Fluid is highly viscous
C absorptivepower,a= Amount of energy absorbed
It cannot be used for measuring the pressure of
gas because gas forms no free surface Amount of energy incident
A Hot Wire Anemometer is used for the
measurement of __________. The absorptive power of a black body is 1 because
A. Pressure of gases B. Velocity of gases
C. Viscosity of gases D. Viscosity of liquids it absorbs radiant energy of all wavelength
B incidents on it.
The technique depends on the convective heat loss
to the surrounding fluid from an electrically heated In a flow field, at the stagnation point _______.
sensing element or probe. If only the fluid velocity
varies, then the heat loss can be interpreted as a A. Pressure is zero
measure of that variable.
Friction drag is generally larger than the pressure B. velocity of fluid is zero
drag in _______.
A. Flow past a sphere C. Pressure head is equal to velocity
B. Flow past a cylinder
C. Flow past an airfoil D. All the velocity head is converted into pressure
D. Flow past a thin sheet head
B
B

a stagnation point is a point in a flow field where

the local velocity of the fluid is zero. Stagnation

points exist at the surface of objects in the flow
field, where the fluid is brought to rest by the
object.

5|Page

www.gradeup.co

48. Viscosity is the most important property in the 53. The locus of elevations that water will rise in a
__________.
Ans. series of pitot tube is called _________.
Sol:
A. Travel of a bullet through air A. Hydraulic grade line
54.
B. Water jet issuing from a fire air B. Pressure head
Ans.
C. Formation of soap bubbles Sol: C. Energy grade line

D. Flow of castor oil through a tube 55. D. head loss

Ans. C C

Sol: if viscosity will be more means fluid will be thick A line that represents the elevation of energy head

and formation of soap bubbles will difficult. (in feet or meters) of water flowing in a pipe,

49. If pressure at any point in the liquid approaches conduit, or channel. The line is drawn above the

the vapor pressure, liquid starts vaporizing and hydraulic grade line (gradient) a distance equal to

creates pockets or bubbles of dissolved gases and the velocity head (V2/2g) of the water flowing at
vapours. This phenomenon is ___________.
each section or point along the pipe or channel.

A. Surface tension B. Adhesion Pressure in Pascal at a depth of 1 m below the free

surface of a body of water will be equal to

C. Vaporisation D. Cavitation _________.

Ans. A A. 1 Pa B. 98.1 Pa

Sol: the tension of the surface film of a liquid caused by C. 981 Pa D. 9810 Pa

the attraction of the particles in the surface layer D

by the bulk of the liquid, which tends to minimize Pressure (p) = ρ ×g×h
surface area.
Density of water (ρ) = 1000kg/m^3

50. The fluid forces considered in the Navier-Strokes Gravitational acceleration (g) = 9.81 m^3/sec
equation are ________.
Depth (h) =1m

A. Gravity, pressure and viscous P=1000×9.81×1 = 9810Pa

B. Gravity, pressure and turbulent Water flows up a tapered pipe as shown in the

C. Pressure, viscous and turbulent figure. What is the magnitude of the deflection h of

D. Gravity, viscous and turbulent the differential mercury manometer corresponding

Ans. A to a discharge of 126 L/s?

Sol: forces considered in the Navier-Strokes equation- The friction in the pipe can be completely

1. Inertial forces neglected.

2. Pressure forces

3. Viscous forces

4. The external forces applied to the fluid

51. Hydraulic grade line for any flow system as

compared to energy line is _______.

A. Above B. Below

C. At same level D. Uncertain

Ans. B

Sol: The energy grade line (EGL) and the hydraulic grade

line (HGL) are defined as the height of the total

Bernoulli constant while HGL is the height to which

liquid would rise in a piezometric tube attached to

the pipe HGL is obtained as EGL minus the velocity

head . The fall of the EGL reflects the energy losses
in the system. EGL drops slowly due to friction

losses and it drops sharply due to a major loss (a

valve or transition) or due to work extraction (to a
turbine). The EGL can rise only if there is work

addition (as from a pump).

52. To avoid vaporization in the pipe line, the pipe line

over the ridge is laid such that t is not more than

____________. A. 16.28 cm B. 17.28 cm

A. 2.4 m above the hydraulic gradient C. 19.28 cm D. 25.28 cm

B. 6.4 m above the hydraulic gradient Ans. C/B
Sol:
C. 10.0 m above the hydraulic gradient P1= pressure at section 1

D. 5.0 m above the hydraulic gradient P2= pressure at section 2

Ans. A/B = density of water

Sol: In order to avoid vaporization in the pipe line, the = density of mercury
pipe line over the ridge is laid in such a way that it
=distance

is not more than 6.4 m above the hydraulic h =distance.

gradient S=Density of mercury

Consider Section 1 as datum line

6|Page

www.gradeup.co

1 2 58. For laminar flow in a pipe, V is equal to
+ + ℎ = + + ℎ + 0.8 Ans.
1 2 Sol: A. Umax B. 0.5 Umax
− − 0.8 = ( − 1)ℎ
= (13.6-1)h 59. C. 0.25 Umax D. 2 Umax

Ans. B
Sol:
= 12.6h 60. average velocity = (discharge/area of pipe)

By continuity Ans. Discharge   d 2u(max.)
Q = × 1^2 × 1 Sol: 4
Q = 4 × 2^2 × 2 61.
u (max) = maximum velocity
4 Ans.
Sol: Water at 20℃ flowing through a 20 cm diameter
D1=30cm
62.
D2=15cm pipe. Take kinematic viscosity of water at 20℃ is
Ans.
Hence Sol: equal to 0.0101 stoke. Assume that the changes
63.
V1=1.6977m/sec from lamina to turbulent at Re=2320. The critical
Ans.
V2=6.79m/sec velocity will be __________.

1 12 2 22 A. 1.117 cm/sec B. 11.17 cm/sec
+ 2 + 1 = + 2 + 2
C. 111.7 cm/sec D. 1.117 m/sec

1 p2 12 − 22 A

− + 0 − 0.8 = 2 Re= = 2320  .01011000 =1.1716cm/sec
20 1000
=6.792−1.69772

2×9.81 Surge wave is an example of ___________.

=2.2034

1 − 2 − 0.8 = 12.6ℎ=2.2034 A. Steady uniform flow

B. Steady non-uniform flow

h =0.175m C. Unsteady uniform flow

h=17.5cm

56. If a pump is handling water and its discharging a D. Unsteady non-uniform flow

Ans. certain flow Q at a constant total dynamic head D
Sol: Because surge wave have flow at varying rates
57. requiring a definite B.H.P., the same pump when through a duct of non-uniform cross-section.

Ans. handling a liquid of specific gravity 0.75 and
Sol:
viscosity nearly same as of water would discharge Quick return mechanism is an inversion of
__________.
A. same quantity of liquid

B. 0.75Q A. Four bar chain
B. Single slider crank chain
C. Q/0.75 C. Double slider crank chain

D. 1.5Q

A D. Crossed slider crank chain

If the discharge of water is Q at constant dynamic B

head and having definite B.H.P if a liquid is having The slider-crank mechanism is a particular four-bar
linkage configuration that converts linear motion to
specific gravity .75 rotational, or vice versa if it having single chain
then it is called single chain slide crank its vice
Then the discharge is 0.75Q because Q is depend versa is also called quick return mechanism

Specific gravity.

A 20cm diameter pipe 5000 metres long conveys

0.05 cumec of water which is to be pumped In gears, interference takes place when _______.
A. Tip of a tooth of a mating gear digs into the
through a height of 6 metres. What is the horse
portion between base and root circles
power required by the pump, if its efficiency is B. Gears do not move smoothly in the absence of

75%? (take 4f=0.006) lubrication

A. 74.2 HP B. 74 HP

C. 75 HP D. 50 HP

A C. Pitch of the gear is not same

Z2 – Z1 = 6m D. Gear teeth are undercut

Efficiency (n) =75% A

4f = 0.006 because interference take place due to frictional
forces in gear when tooth dig between the circle
Loss of head in the pipe line, between root and base it causes frictional force

hf = 4 2
3.0257 5
4×0.006×6×0.052 In a multiple V belt drive, when a single belt is
hf = 3.0257(02)5 damaged, it is preferable to change the complete
set to _______.
hf =77.46m

Head to be developed by the pump, A. Reduce vibration

h = 77.46 + 6 = 83.46m B. Reduce slip

ℎ
HP required = 75 C. Ensure uniform loading

HP required = 100 × 0.05 × 83.46 D. Ensure proper alignment

75 × 0.75 D/C
For uniform loading it is preferable to change the
=74.2HP complete set of V-belt drive.

7|Page

www.gradeup.co

64. The center of gravity of the coupler link in a 4-bar 69. The shock absorbing capacity of a bolt can be

Ans. mechanism would experience _______. Ans. increased by _______.
Sol: Sol:
A. No acceleration A. Tightening it properly
65. 70.
Ans. B. Only linear acceleration Ans. B. Increasing shank diameter
Sol: Sol:
C. Only angular acceleration C. Grinding the shank
71.
D. Both linear and angular accelerations D. Using washer
Ans.
D Sol: C
72.
A four-bar linkage, also called a four-bar, is the Ans. capacity of a the shank bolt is the shock absorbing
Sol:
simplest movable closed chain linkage. It consists increase by grinding
73.
of four bodies, called bars or links, connected in a Ans. Because if we turn down the shank it is subjected
Sol:
loop by four joints. Generally, the joints are to high stress that increases the strain absorbing
74.
configured so the links move in parallel planes, and Ans. capacity
Sol:
the assembly is called a planar four-bar linkage Which if the following key is under compression

and in such type of linkages the body moves in rather than in being shear when under load?

both linear and angular motions so it have both A. Saddle B. Barth

kind of velocities C. Feather D. Kennedy

The amplitude of underdamping a small damping B

varies with time as ________. The Barth key is a square key with bottom two

A. Linearly B. Arithmetically corners beveled. This double beveling ensures that

C. Geometrically D. Exponentially the key will fit tightly against the top of the keyway

D when the drive is in either direction and lessens the

tendency to twist.

Shaft is subjected to which of the following

stresses?

A. Bending

B. Torsional

C. Both bending and torsional

D. None of these

C

it is subjected both kind of stresses because shaft

66. Whirling speed of a shaft coincide with the natural is working under dynamic load and dynamic load

Ans. frequency of the ______. have both kind of stresses to
Sol:
67. A. Longitudinal vibration Which of the following is self-aligning bearing?

Ans. B. Transverse vibration A. Conical B. Spherical

68. C. Torsional vibration C. Rectangular D. None of these
Ans.
Sol: D. Coupled between torsional vibration B

B Self-aligning ball bearings have two rows of balls, a

Transverse vibrations because whirling of the shaft common sphered raceway in the outer ring and two

is dependent on the transverse vibration also it deep uninterrupted raceway grooves in the inner

may be rotational vibration. ring. They are available open or sealed. The

A mass of 1 kg is attached to the end of a spring bearings are insensitive to angular misalignment of

with stiffness 0.7 N/mm. The critical damping the shaft relative to the housing.

coefficient of this system is __________. Which of the following is Trapezoidal thread?

A. 1.40 Ns/m B. 18.522 Ns/m A. Acme B. Square

C. 52.92 Ns/m D. 529.20 Ns/m C. Buttress D. All options are correct

C A

K=0.7N/mm=700N/m Trapezoidal thread forms are screw thread

M=1kg profiles with trapezoidal outlines. They are the

Coefficient=2×Sqrt(KM). most common forms used for leadscrews (power

=2 × Sqrt (700*1). screws). They offer high strength and ease of

= 52.92 N-s/m manufacture. They are typically found where large

Rankine’s theory of failure is applicable for which of loads are required, as in a vise or the leadscrew of

the following type of materials? a lathe. Standardized variations include multiple-

A. Brittle B. Ductile start threads, left-hand threads, and self-centering

C. Elastic D. Plastic threads (which are less likely to bind under lateral

A forces).

(A) Rankine's Theory assumes that failure will The efficiency of self-locking screw is __________.

occur when the maximum principal stress at any A. More than 50% B. Less than 50%

point reaches a value equal to the tensile stress in C. Equal to 50% D. None of these

a simple tension specimen at failure. This theory B

does not take into account the effect of the other Efficiency of self-locking screws is less than 1/2 or

two principal stresses. Rankine's theory is 50%. If the efficiency is more than 50%, then the

satisfactory for brittle materials, and not applicable screw is said to be overhauling.

to ductile materials.

8|Page

www.gradeup.co

75. The most suitable bearing for carrying very heavy 80. When two mutually perpendicular principal stresses
Ans. are unequal but alike, the maximum shear is
Sol: loads with slow speed is _________. Ans. represented by __________.
76. Sol: A. The diameter of the Mohr’s circle
A. Hydrodynamic bearing B. Half the diameter of the Mohr’s circle
Ans. C. One-third the diameter of the Mohr’s circle
B. Ball bearing D. One-fourth the diameter of the Mohr’s circle
77. B
Ans. C. Roller bearing

D. Hydrostatic bearing

D

Hydrostatic bearings are externally pressurized

fluid bearings, where the fluid is usually oil, water

or air, and the pressurization is done by a pump.

The outside diameter of a hollow shaft is twice it’s

inside diameter. The ratio of its torque carrying

capacity to that of a solid shaft of the same

material and the same outside diameter is

__________.

A. 15/16 B. 3/4

C. 1/2 D. 1/16

A

The strength of a solid shaft in torsion is given by, Its half of the dia. Shows the maximum stress at

T1(solid shaft) = (π/16)*max stres×D^4 angle is 45° so radius of the circle shows the
T1= × × 4
maximum stress.
16
81. The plane of maximum shear stress has normal
T2 (hollow shaft)=(π/16)*(max stres)*(D^4- Ans.
Sol:
d^4)/D 82. stress that is _________.
. T2= × × (2 4 − 4)
Ans. A. Maximum B. Minimum
16 Sol:
C. Zero D. None of these
1= 15/16 83.
C
2 Ans.
Sol: because of maximum shear stress theory according
A solid shaft can resist a bending moment of 3

kNm, and a twisting moment of 4 kNm together, to it the plane at which the maximum shear stress

then the maximum torque that can be applied is acts then there will be no normal principle stresses.

__________. Consider the following theories of failure:

A. 7.0 kNm B. 3.5 kNm A. Maximum stress theory

C. 4.5 kNm D. 5.0 kNm B. Maximum strain theory

D C. Maximum shear stress theory

Equivalent Torque= D. Maximum energy or distortion theory

T0  M 2  T 2  32  42  5 kNm The most suitable for ductile material is

78. Under torsion, brittle materials generally fail A. A and B B. A and C
___________.
A. Along a plane perpendicular to its longitudinal C. A and D D. C and D
axis
B. In the direction of minimum tension D
C. Along surfaces forming a 45° angle with the
longitudinal axis 1. Maximum Principal Stress theory also known as
D. Not in any specific manner
RANKINE’S THEORY
Ans. C
Sol: because torsion take place at the principle axis of 2. Maximum Shear Stress theory or GUEST AND

specimen by the eular Bernoulli equtions TRESCA’S THEORY

3. Maximum Principal Strain theory also known as

St. VENANT’S THEORY

4. Total Strain Energy theory or HAIGH’S THEORY

5. Maximum Distortion Energy theory or

VONMISES AND HENCKY’S THEORY “c” and “d”

79. The shear stress distribution over a rectangular option is correct.
cross-section of a beam follows _______.
Ans. A. A straight line path B. A circular path For ductile materials, the most appropriate failure
Sol: C. A parabolic path D. An elliptical path
C theory is _______.

A. Maximum shear stress theory

B. Maximum principal stress theory

C. Maximum principal strain theory

D. Shear strain energy theory

A

“Ductile materials have typically equal strength in

tension and compression, whereas compressive

strength of brittle material is much higher than

tensile strength.”

Maximum shear stress theory assumes that yield

strength in tension is equal to yield strength in

compression hence this theory is best suited for

ductile material and not brittle material.

9|Page

www.gradeup.co

84. All the failure theories give nearly the same result 89. For an element under the effect of biaxial state of
Ans. normal stress, the normal stresses are on a 45°
Ans. _________. plane is equal to __________.
Sol: A. Difference of normal stresses
85. A. When one of the principal stresses at a point is B. Sum of normal stresses
C. Half of the sum of normal stresses
Ans. larger in comparison to the other D. Half of the difference of normal stresses
Sol: C
86. B. When shear stresses act

Ans. C. When both the principal stresses are

numerically equal

D. For all situations of stress

A

because situation reassemble the uniaxial tension

test

from the hypothesis given by Rankine, the criteria

for failure of brittle material is ______.

A. Maximum principal stress

B. Maximum strain energy

C. Maximum shear stress

D. Maximum shear strain energy  
2
A   x y when,  450

Maximum principal stress theory is best suited for

the brittle materials because brittle materials do 90. For a thin spherical shell subjected to internal
Ans.
not fail by yielding but they fail by fracture. pressure, the ratio of volumetric strain to
91.
In a closed helical spring subjected to an axial Ans. diametrical strain is ___________.
Sol:
load, other quantities remaining the same, if the A. 5 : 4 B. 3 : 2
92.
wire diameter is doubled and mean radius of the Ans. C. 2 : 1 D. 3 : 1
Sol:
coil is also doubled, then stiffness of spring when D

compared to original one will become __________.

A. Twice B. Four times Volume of sphere V=

C. Eight times D. Sixteen times Taking differential on both side

A V  3   d 2 d
6
spring stiffness: The stiffness is defined as the

load per unit deflection therefore V d
V d
 3

So, option D is correct.

Stud and projection welding belong to the following

category of welding ________.

A. gas welding B. arc welding

W = axial load C. resistance welding D. pressure welding

D = mean coil diameter,d = diameter of spring C
wire,n = number of active coils,C = spring index =
Stud welding, also known as "drawn arc stud
D / d For circular wires,l = length of spring wire,G welding", joins a stud and another piece of metal
together by heating both parts with an arc. The
= modulus of rigidity,x = deflection of spring stud is usually joined to a flat plate by using the
stud as one of the electrodes. The polarity used in
87. The Poisson’s ratio for most of the materials is stud welding depends on the type of metal being
used. Welding aluminum, for example, would
Ans. close to _________. usually require direct-current electrode positive
Sol: (DCEP). Welding steel would require direct-current
A. 1 : 2 B. 1 :3 electrode negative (DCEN).
88.
C. 1 : 4 D. 1 : 5
Ans.
Sol: B

This data is experimentally proved Electrode gets consumed in the following welding
For perfect isotropic Material, Poisson’s Ratio: 1:4,

but for most materials it lies between 0.28 to 0.33 process _______.

so Option B is correct A. gas B. resistance

True stress represents the ratio of ___________. C. thermit D. arc

A. Average load and average are D

B. Average load and maximum area electrode are useful in arc welding only.

C. Maximum load and maximum area One of the most common types of arc welding

D. Instantaneous load and instantaneous area is shielded metal arc welding (SMAW), which is also

D known as manual metal arc welding (MMAW) or

true stress is define as the ratio of instantaneous stick welding. An electric current is used to strike

force and instantaneous area an arc between the base material and a

consumable electrode rod or stick.

10 | P a g e

www.gradeup.co

93. The strength of a properly welded joint as Ans. A
Sol:
Ans. compared to base metal would be _____. because Foundry shop is the place where the
Sol: 98.
94. A. same B. more metal casting is prepared by melting and pouring
Ans.
Ans. C. less D. unpredictable Sol: the molten metal into moulds
Sol:
B Which of the following processes would produce
95.
The strength of weld bead that is the portion which strongest components?
Ans.
Sol: is welded is always higher and that is because of A. die casting B. hot rolling
96.
the Alloy formation. C. extrusion D. forging
Ans.
Oxygen to acetylene ratio in case of carburising A
97.
flame is _______. Die casting is a metal casting process that is

A. 0.5: 1 B. 0.9: 1 characterized by forcing molten metal under high

C. 1: 1 D. 1 : 1.2 pressure into a mold cavity. The mold cavity is

B created using two hardened tool steel dies which

In oxy-acetylene welding, a carburizing flame is have been machined into shape and work similarly

one with little oxygen, which produces a sooty, to an injection mold during the process. Most die

lower-temperature flame and oxygen to castings are made from non-ferrous metals,

acetylene ratio is 0.9:1 specifically zinc, copper, aluminium, magnesium, le

For steel castings, the following type of sand is ad, pewter and tin-based alloys. Depending on the

better ___________. type of metal being cast, a hot- or cold-chamber

A. fine-grain B. coarser-grain machine is used.

C. medium grain D. fine-grain, coarser-

grain and medium grain all are equally good 99. A sprue hole is ____________.

B A. a casting defect

because B. a hold made for riveting

Hot tear refers to _________. C. a blind hole in jigs

A. casting defect D. an opening in mould for pouring molten metal

B. process of fabrication Ans. D

C. process of heat treatment Sol: sprue: it is define as the passage by which molten

D. weathering of non-ferrous materials metal will pour into the mould cavity

A 100. Coining is the operation of __________.

It is a defect in which when the material in process A. cold forging B. hot forging

to solidify some crack are visible this is called hot C. cold extrusion D. piercing

tear it causes due to gases escape from the molten Ans. A

metals. Sol: Coining is a closed die forging process, in which

Slick in a foundry shop is used to ________. pressure is applied on the surface of the forging in

A. make and repair corners in a mould order to obtain closer tolerances, smoother

B. thoroughly mix up moulding sand surfaces and eliminate draft.

C. make venting holes in the mould

D. prepare gates

***

11 | P a g e