SSC JE MECHANICAL PAPER

1 Define pure substance ?

ASubstance which is available in the purest form in nature
BSubstance with non-uniform composition
CA single substance without any mixture
DSubstance with fixed chemical composition throughout

2 The specific gravity of water at standard atmospheric conditions is ?

A1
Bgreater than 1
C0
Dless than 0

3 Which of the following statements is more relevant?

AIn the Eulerian method, control volume approach is not used.
BIn the Lagrangian approach, a fluid particle of fixed mass is considered.
CIn kinematics of fluid flow, pressure is a vector field.
DFluid kinematics deals with the action of the forces in producing or changing motion of fluid.

4 In a triple fluid vapour absorption refrigeration system, hydrogen gas is used to ?

Aimprove system performance
Bcirculate the refrigerant
Creduce partial pressure of refrigerant in evaporator
Dprovide vapour seal

5 In the context of aircraft refrigeration cycle, what is temperature of air at the exit

of cooling turbine in the absence of moisture condensation?

ADry air temperature (DAT)
BSuper-saturated temperature
CDry air rated temperature (DART)
DSaturated temperature

6 Which of the following statements is INCORRECT in the context of static fluid pressure?

AIt exerts force normal to the walls of the container.
BIt is independent of shape or area of the container.
CIt is directly proportional to depth of fluid.
DAt any particular depth. it changes with direction.

7 The fourth stage of the compression ignition process is ?

Aignition delay period
Bburning on the expansion stroke
Cperiod of rapid or uncontrolled combustion
Dperiod of controlled combustion

8 The refrigerant used in the VCR based refrigerant cycle rejects heat in _____ ?

Athe expansion valve
Bthe condenser
Cthe compressor
Dthe evaporator

9 For a Kaplan turbine, the value of speed ratio is _____ ?

A0.9
B0.5
C0.1
D2

10 While loading, _______ material undergoes fracture after large amount of deformation ?

Aisotropic
Bplastic
Cbrittle
Dductile

11 With respect to the first law of thermodynamics, which of the following statements is the most relevant?

AEnergy can be created or destroyed depending on the source of input
BEnergy is always conserved
CA process that involves transfer of heat energy is irreversible
DThere is a natural tendency for any system to degenerate into a disordered state

12 Which of the following helps to increase efficiency of the Rankine cycle?

AIncreasing the condenser pressure
BIncreasing average temperature at which heat is rejected from the working fluid
CIncreasing average temperature at which heat is transferred to the working fluid
DOperating at constant temperature

13 In Lancashire boilers, the feed water tube is ?

Athin conduit
Bopen channel type
Csolid
Dperforated

14 A fusible plug must be used primarily for safety purposes in which of the following types of boilers ?

AOil-fired boiler
BHigh-pressure boiler
CMarine type boiler
DFire-tube boiler

15 Which refrigeration system is driven by low-grade energy?

ASteam jet refrigeration
BVortex tube systems
CGas cycle refrigeration
DThermo-electric refrigeration

16 In the context of fluid mechanics, which of the following statements is INCORRECT?

AFluid cannot sustain any shear stress when at rest.
BFluid continues in motion under the application of shear stress.
CFluid does not deform continuously under shear stress.
DFluid deforms under very small shear stress.

17 For a static fluid, the increase of pressure at any point inside the fluid, in a vertically downward direction, must be equal to the product of the of the fluid and depth from the free surface ?

Aspecific gravity
Bdensity
Cviscosity
Dspecific weight

18 Which of the following is the working fluid in an air-cycle refrigeration system?

ASaturated air
BCompressed air
CAir at high Mach number
DGas

19 The benchmark pressure above which a boiler is considered to be a high- pressure boiler is ?

A70 bar
B60 bar
C80 bar
D50 bar

20 Which of the following is NOT considered as external loads?

AThose arising from fluid pressure
BThose arising from service conditions
CThose arising from cohesion of material
DThose arising from environment

21 ______ is also called spheroidal graphite cast iron ?

ADuctile cast iron
BMalleable cast iron
CWhite cast iron
DGray cast iron

For a carburising flame, the flow of ______ is kept higher ?

Aargon
Bnitrogen
Coxygen
Dacetylene

23 Under what condition of fluid flow does shear stress NOT exist?

ARelative motion exists between fluid layers
BFluid in low velocity motion
CNegligible viscosity
DFluid in high velocity motion

24 Another name for the Bell-Coleman cycle is ?

ACarnot cycle
Breversed Carnot cycle
Cideal reverse Brayton cycle
DRankme cycle

25 With respect to reaction turbines, which of the following statements is relevant?

AGoverning of reaction turbines is done by altering position of the guide vanes.
BFlow rate cannot be controlled by changing the gate openings to the runner.
CWater does not flow through a scroll casing.
DGuide blades are not connected to the regulating ring.

26 Which of the following is the best example of a thixotropic fluid?

AToothpaste
BMinerals in suspension
CFly ash
DPrinting ink

27 What happens when a fluid is at rest?

AFrictional force is present
BInternal deformation is considerable
CFluid element will not be subjected to normal and shear component
DThere is no shear component

28 Nominal volume generated by the working piston when travelling from one dead centre to the next is called ?

Aclearance volume
Bswept volume
Ctotal volume
Dstroke volume

29 What is the unit of surface tension?

AN/m
Bkg/m
CN
DN-m

30. Aircraft engines use ________ for cooling engines ?

Aan air-cooled system
Ba thermo-syphon cooling system
Ca water-cooled system
Da forced cooling system

31 Which of the following characteristics of a centrifugal pump is vital?

ASlip will decrease with the increase in flow rate
BThere will be no whirl component of velocity at the entry to impeller
CFluid is considered to have friction while flowing inside the pump
DFluid moves normal to the blade

32 What is radiant heating in the context of boilers?

AHeating process carried out using radiation effect
BSaturated steam is re-circulated and super-heated
CHeating done on external walls only by reflecting radiant energy
DHeating done on radial tubes

33 An appurtenance whose length generally does NOT exceed three times of its diameter is called ?

Aan orifice
Ba diffuser
Ca non-return valve
Da mouthpiece

34. In actual compressors, there is a clearance between the cylinder head and piston to take care of thermal expansion. Identify the correct expression from the given options, where C is the clearance (in mm) and L is the stoke length (in mm) ?

AC = (0.005L + 0.5)
BC = (0.05L + 0.05)
CC = (0.005 + 0.5L)
DC = (0.05L + 0.5)

35. The major function of a steam nozzle is to ?

Aproduce low viscosity steam
Bproduce low velocity jet of steam
Cproduce high viscosity steam
Dproduce high velocity jet of steam

36. A member of length 200 mm and diameter 25 mm is subjected to a tensile load of 20 kN. The final length of the member is found to be 220 mm. The percentage increase in the length of the member is ?

A1%
B10%
C5%
D20%

37. At sea level, under normal conditions, what is the atmospheric pressure?

A104.013 kPa
B100.043 kPa
C101.32 kPa
D100.1 kPa

38. How is a high-pressure boiler classified?

AWhen it operates, high amount of steam is required for the operation of the cycle
BWhen pressure > 50 bar
CWhen velocity of water is very low
DWhen pressure > 80 bar

39 Which of the following does NOT result in poor performance of boilers?

APoor combustion
BSurface fouling
CPoor water quality
DBoiler mounting

40. Which is the most practical fluid for the Rankine cycle?

AFuel
BAir
CAir-fuel mixture
DWater

41. What is a dilatant?

AIt is a shear thickening fluid.
BIt is a fluid with suspended colour pigments.
CIt is a fluid that sustains shear stress without ally deformation.
DIt is a shear thinning fluid

42. According to Kelvin-Planck’s statement of the second law of thermodynamics, which of the following statements is correct?

AIt restricts the thermal efficiency of the heat engine to be lesser than unity.
BHeat from a source should be rejected to a high temperature sink.
CIt restricts the mechanical efficiency of the heat engine to be lesser than unity.
DThermal efficiency of the heat engine will be unity.

43. Fans and blowers of turbo machines ?

Aa higher static pressure will prevail
Bdeliver air at a higher desired velocity
Cdeliver air at a lower mass flow rate
Dspiral casing decreases the static pressure

44. What is the function of a fly wheel in IC engines?

ATo absorb energy during suction stroke
BTo maintain constant speed
CTo increase the speed
DTo circulate air in the engine for cooling

45. What is a gauge pressure?

AIt is pressure measured relative to local atmospheric pressure.
BIt is an alternate name of datum pressure.
CIt is the same as local atmospheric pressure.
DIt is pressure measured relative to a perfect vacuum.

46. Which of the following is an inferential type of flow meter?

ARotameter
BMagnetic flowmeter
CLaser doppler
DPurge flow regulator

47. A single stage impulse turbine is also known as ?

Ade Laval turbine
BCurtis stage turbine
Creaction turbine
DRateau turbine

48. _______ is the ability of steel to resist stresses that are reversal in nature ?

AImpact strength
BToughness
CHardness
DFatigue strength

49. Which of the following statements is correct with reference to perpetual motion machines of the first kind?

AIt violates the second law of thermodynamics.
BIt produces heat without receiving work input.
CIt produces work without receiving heat.
DIt is a reversible process.

50. In a flow-measuring device, what is velocity head?

AFree rise of liquid column in an open-ended rube
BDifference in elevation in the flow direction
CVertical distance through which a column of the flowing liquid would rise in an open-ended tube
DFree fall of liquid column to attain a given velocity freely

51 For a single cylinder four-stroke oil engine, indicated power is 15 kW. calorific value of fuel is 40000 kJ/kg and fuel consumed is 0.001 kg/s. What will be the indicated thermal efficiency?

A62.5%
B40%
C75%
D37.5%

52 Identify the requirement of a good boiler from the following options ?

AIt should have more flexible joints.
BIt should be light in weight and compact.
CIt should be able to produce steam at minimum pressure.
DIt should use maximum refractory material.

53 Which of the following statements is INCORRECT with reference to the first law of thermodynamics?

AEnergy transfer to a system from its surroundings is a positive quantity
BWork done by a system on its surroundings is a positive quantity
CHeat interaction is a path function
DEnergy transfer is a point function

54 In air standard cycle analysis of IC engines, which of the following statements is correct?

ASpecific heats (Cp, Cv) of air vary with temperature.
BThere will be a sudden change in chemical equilibrium of the working fluid.
CThere are no intake or exhaust processes.
DCompression and expansion processes are considered as irreversible

55 When water is about to vapourise it is called?

Asub-cooled liquid
Bsuper-heated vapour
Csaturated vapour
Dsaturated liquid

56 Which of the following statements is more relevant in the context of IC engines?

ACompression Ignition (CI) engines have lesser weight than SI engines.
BCompression ratio for air is in the range of 16 to 20 for SI engines.
CWalls of the engine cylinder of SI engines need to be thicker than CI engines.
DCompression ratio of the fuel-air mixture is in the range of 6 to 10 in Spark Ignition (SI) engines.

57 The COP (coefficient of performance) of a heat pump is always _______ the COP of a refrigerator ?

Aless than or equal to
Bgreater than
Cless than
Dequal to

58 A thermoelectric refrigeration system requires ?

Alow voltage AC
Blow voltage DC input
Chigh voltage AC input
Dhigh voltage DC input

59 In a compressor, work is done by ?

Athe rotor on the fluid element
Ba static component known as impeller
Cthe fluid on the rotor
Dthe rotating part called stator

60 Under what condition is an inclined manometer used?

AWhen u-tube manometer is not available
BWhen surface of measurement is inclined
CIn high pressure range
DIn small pressure changes

61 With respect to head loss of flowing fluid, select the most appropriate statement ?

AIncrease in velocity in a flow induces large-scale turbulence
BEnergy loss is nor caused by change in velocity
CEnergy loss is not due to formation of eddies
DPortion of energy loss will not be dissipated as heat

62 Which of the following pairs is NOT an example of a lower pair?

APrismatic pair
BHelical and cylindrical pair
CRevolute pair
DRolling ball on a flat surface

63 In the context of the Reynolds transport theorem, which of the following statements is the most appropriate?

AIt uses deforming control volume.
BIt links system and control volume approaches.
CIt uses fixed control volume.
DIt does not use control volume approach.

64 If compression is achieved by trapping a refrigerant vapour in an enclosed space and then reducing its volume, then it is called ?

Aradial-flow type compressor
Bpositive-displacement type compressor
Copen type compressor
Droto-dynamic type compressor

65 Which of following is NOT a phase in steel?

AAustenite
BMartensite
CLimonite
DPearlite

66 Which of the following is NOT a projectile motion?

AA bullet fire d from a gun
BA stone thrown in any direction
CA stone thrown horizontally from a building
DA car moving in a straight line

67 In isentropic compression, similar to aircraft refrigeration cycle, what is ram efficiency?

ARatio of input to output ram pressure
BIt is proportional to mass flow rate
CRatio of actual pressure rise to isentropic pressure
DRatio of aircraft velocity to sonic velocity

68 Define a machine in terms of its basic objective ?

AA device to transform force.
BA device to transfer load to source.
CA device used to transfer force.
DA device to transfer and transform motion and force from source to load.

69 What is the unit of absolute viscosity?

ACentipoise
BSaybolt universal unit
CCentistoke
DViscosity index

70 Identify the method by which steel is NOT classified ?

AManufacturing method
BBased on notch toughness
CBased on heat treatment
DBased on chemical composition

71 Which of the following is NOT a water-tube boiler?

ALaMont boiler
BLoeffler boiler
CStirling boiler
DCornish boiler

72 What is a diffuser?

AIt is a type of nozzle
BIt is voltage regulator
CIt is a type of valve that decreases pressure
DIt is a duct which decreases the velocity and increases pressure.

73 What is the flow called if the velocity at a given instant is the same in both magnitude and direction throughout the flow domain?

ALaminar flow
BSteady flow
CTurbulent flow
DUniform flow

74 An ideal constant pressure gas turbine works on the ________ cycle ?

AStirling
BLenoir
CBrayton
DAtkinson

75 The air fuel ratios used in a compression ignition engine lie in the range of ?

A18 to 25
B6 to 14
C40 to 48
D28 to 36

76 Which of the following statements is INCORRECT with respect to water rube boilers?

AThey are smaller and lesser in weight
BThey are suitable for high steam pressure
CThey cannot handle high steam pressure
DThey are suitable for large gas flows

77 In the context of moving control volume, which of the following statements is more relevant?

AAbsolute velocity of fluid carries fluid a cross the control volume
BDifference between absolute and relative velocities of fluid is the velocity across moving control volume
CControl volume is considered as a fixed volume in space
DRelative velocity of fluid carries fluid across the control surface of moving control volume

78 _______ states that “pressure of a gas mixture is equal to the sum of the pressures each gas would exert if it existed alone at the mixture temperature and volume” ?

ADalton’s law of additive pressures
BIdeal gas law
CHooke’s law
DAmagat’s law of additive volumes

79 Lithium bromide is used as an absorbent in _______ ?

AElectrolux refrigerators
Bsteam jet refrigeration
Cvapour absorption refrigeration
Dvapou compression refrigeration

80 A continuity equation for two dimensional compressible flow is given by ?

81 Which of the following links does NOT undergo any deformation while transmitting motion?

AResistance link
BFlexible link
CRigid link
DFluid link

82 Identify the complete and correct statement of the first law of thermodynamics ?

AWhen a closed system executes a complete cycle, the sum of heat interactions is equal to the sum of work interactions.
BWhen a system undergoes a cycle, the integral of heat is equal to the integral of work.
CDifference between the heat and work interactions during a process, which is property of the system.
DDuring a process, extracting work without supplying heat, while sacrificing the energy of the system.

83 Which of the following is the characteristic of an isochoric process?

AProcess during which no mass is transferred
BProcess during which specific volume remains constant
CProcess applied to impure substances
DProcess during which no heat is transferred

84 Which of the following statements is relevant?

AFluid deforms under constant shear stress.
BFluid can sustain shear stress when at rest.
CFluid deforms continuously under the action of shear stress of even very low magnitude.
DFluid does not deform continuously under the action of shear stress.

85 Heat and work both are ?

Apoint functions
Bpoint and path functions both
Cpath functions
Dstate functions

86 With respect to the term kinematic viscosity, which of the following statements is more relevant?

AIt is an indicator of absolute tendency of the fluid.
BDenominator represents physical property of the fluid to maintain its momentum.
CDenominator represents propagation of disturbance.
DNumerator represents property of the fluid to maintain its momentum.

87 What is a degree-of-freedom in the context of kinematics?

AMaximum independent coordinates to describe the configuration
BMinimum dependent coordinates to describe the configuration
CMinimum independent variables specified to fix the configuration
DMaximum dependent variables specified to describe the configuration.

88 Which of the following is NOT a maintenance method of a boiler?

AShort-term lay-up
BChemical lay-up
CDry lay-up
DWet lay-up

89 Define strain energy ?

AIt refers to change in length of a ball.
BIt refers to external work done on a bar.
CIt is the potential energy stored by an elastic body when deformed
DIt is the energy released by a bar during loading process.

90 According to IBR regulations, boilers exceeding _______ need regular inspection and certification ?

Acapacity of more than 15 litres
Bcapacity of more than 50 gallons
Ccapacity of more than 5 gallons
Dcapacity lesser than 5 gallons

91 A centrifugal pump ?

Aflow is radially outwards in this pump
Bworks on the same principle as that of a Francis turbine
Cfluid gain is through constant head
Dflow is tangential in this pump

92 Intercooling in multistage compression reduces __ ?

Athe volume of free air delivered
Bthe work input to compressor
Cthe pressure of air at delivery
Dthe index of compression

93 Boilers in the Rankine cycle are used ?

Ato maintain heat in the process
Bto store working fluid
Cto allow expansion of steam
Dfor steam generation

94 The Rankine cycle is an ideal cycle for vapour power plants because?

Ait does not allow isentropic expansion
Bit includes reversible processes
Cwater enters the pump at unsaturated state
Dsteam is not condensed in the condenser

95 The compression ratio of a Compression Ignition (CI) engine is ?

A< 5
B12 to 22
C5 to 10
D10 to 15

96 Why do engines need to be cooled?

ATo regulate mass transfer
BTo improve compression volume
CTo reduce ignition temperature
DTo avoid pre-ignition and knocking

97 Select the most appropriate definition of a turbine from the following statements ?

AIt is a device where mechanical energy from moving parts is transferred to a fluid.
BIt is device in which kinetic energy held by a fluid is converted to mechanical energy of a rotating member.
CIt is a device where potential energy is transferred to a fluid.
DTurbine is a fluid machine.

98 One ton of refrigeration is equal to _______ kW ?

A1
B3.5
C2.5
D5

99 The Lagrangian description of fluid field is more computational because ?

Avelocity field is a continuous function distribution with position and time
Bvariation of velocity is expressed in Cartesian coordinates
Cit is required to track movement of a large number of fluid particles with time
Dvelocity of the fluid particle is the same as the local velocity

100 What is sonic speed?