i3619214IAS-Pre-Mechanical Engineering Previous Paper 2004

7/30/2019 i3619214IAS-Pre-Mechanical Engineering Previous Paper 2004

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1. Consider the cantilever loaded as shownbelow:

What is the ratio of the maximumcompressive to the maximum tensile

stress?a. 1.0b. 2.0c. 2.5d. 3.0

2. A closed coil helical spring has 15 coils. If five coils of this spring are removed bycutting, the stiffness of the modified springwilla. increase to 2.5 timesb. increase to 1.5 timesc. reduce to 0.66 timesd. remain unaffected

3. For 1 2 and 3 0 = , what is thephysical boundary for Ranking failuretheory?a. A rectangleb. An ellipsec. A squared. A parabola

4. What is the number of instantaneouscenters for an eight link mechanisms?a. 15b. 28c. 30d. 8

5. In an adiabatic process 6000 J of work isperformed on a system. In the non-adiabatic process by which the systemreturns to its original state. 1000 J of heatis added to the system. What is the work done during non-adiabatic process?a. + 7000 Jb. - 7000 J

c. + 5000 Jd. - 5000 J

6. Match List I (Applications) with List II(Choice of Bearings) and select the correctanswer using the codesList IA. Granite table of a coordinate

measuring machineB. Headstock spindle of a latheC. Crank shaft of a diesel engineD. Armature of 0.5 kW induction motorList II1. Hydrodynamic bearing

2. Deep groove ball bearing3. Hydrostatic bearing4. Taper roller bearingCodes;

A B C Da. 1 4 3 2b. 3 3 2 1c. 1 2 3 4d. 3 4 1 2

7. If k = 3 for ball bearings and k = 3.33 forroller bearings, which one of the followingcorrectly states the load (P) - Life (L)relationship for rolling contact bearings?

a. 1 12 2

k L P L P

=

b. 1

12 1

1 2

k L P L P

=

c. 2 11 2

k L P L P

=

d. 1

2 1

1 2

k L P L P

=

8. What is the purpose of a moderator in anuclear reactor?a. Moderate the fission temperatureb. Reduce the speed of fast moving

neutronsc. Reduce I and y raysd. Absorb excess neutrons in the reactor

9. Heat flows between two reservoirs havingtempera tures 1000 K and 500 K.respectively. If the entropy change of the

C.S.E-Pre 2004


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2 of 14cold reservoir is 10 kJ/K, then what is theentropy change for the hot reservoir?a. - 10 kJ/Kb. - 5 kJ/Kc. 5 kJ/Kd. 10 kJ/K

10.

For the rotor system shown in figure, themass required for its complete balancing isa. 1.5 kg at 2 m radius and at 225 from

referenceb. 3 kg at I m radius and at 45 from

reference

c.

8 kg at 1 m radius and at 225 fromreferenced. 4 kg at 2 m radius and at 45 from

reference11.

The figures given above show differentschemes suggested to transmit continuousrotary motion from axis A to axis B.Which of these schemes are notdynamically balanced?a. 1 and 3b. 2 and 3c. 1 and 2d. 1, 2 and 3

12. A spring-mass suspension has a naturalfrequency of 40 rad/s. What is thedamping ratio required if it is desired toreduce this frequency to 20 rad/s by addinga damper to it?a. 3 /2b. 1/2

c. 1/ 2 d. 1/4

13. What will be the maximum efficiency of the pipeline if one-third of the availablehead in flow through the pipeline isconsumed by friction?a. 33.33%b. 50.00%c. 66.66%d. 75.00%

14.

The four bar mechanism shown in thefigure (Given OA = 3 cm, AB = 5 cm, BC= 6 cm, DC = 7 cm) is aa. Double crank mechanismb. Double rocker mechanism

c. Crank rocker mechanismd. Single slider mechanism15. Steam flows at the rate of 10 kg/s through

a supersonic nozzle. Throat diameter is 50mm. Density ratio and velocity ratio withreference to throat and exit arerespectively 2.45 and 0.8. What is thediameter at the exit?a. 122.5 mmb. 59 mmc. 70 mmd. 62.5 mm

16. An attemparator is used in some utilityboilersa. ahead of super heater for initial

superheatingb. for optimizing team output from the

generatorc. to regulate steam pressured. to control degree of superheat

17. Speed reduction in a gear box is achievedusing a worm and worm wheel. The wormwheel has 30 teeth and a pitch diameter of


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3 of 14210 mm. If the pressure angle of the wormis 20, what is the axial pitch of the worm?a. 7 mmb. 22 mmc. 14 mmd. 63 mm

18.

In the figure shown, the sun wheel has 48teeth and the planet has 24 teeth. If the sunwheel is fixed, what is the angular velocityratio between the internal wheel and arm?a. 3.0b. 1.5c. 2.0d. 4.0

19. Which one of the following is satisfied if the flow is irrigational for a two-dimensional fluid element in the x - yplane?

a. v u

x y

=

b. v u x y

=

c. u v x y

=

d. u v x y

=

20. 100 kW power is supplied to the machinethrough a gear box which uses anepicyclical gear train. The power issupplied at 100 rad/s. The speed of theoutput shaft of the gear box is 10 rad/s in asense opposite to the input speed. What isthe holding torque on the fixed gear of thetrain?a. 8 kNmb. 9 kNmc. 10 kNmd. 11 kNm

21. Consider the following statements:In designing a plant layout, a ProductLayout should be preferred if

1. the variety of the products is low.2. the variety of the products is very

large.3. the quantity of production is very small

in each variety4. the quantity of production is very large

in each variety.

5.

the in-process inspection is maximum.6. the in-process inspection is minimum.Which of the statements given above arecorrect?a. 1, 3 and 6b. 1, 4 and 5c. 2, 3 and 4d. 1, 4 and 6

22. Transmissibility is unity at two points.Which one of the following is true forthese two points?a. / n is zero and 3 for all values of

dampingb. / n is zero and 2 for all values of

dampingc. / n is unity and 2 for all values of

dampingd. / n is unity and 3 for all values of

damping23. According to Stablers rule, in oblique

cutting the chip flow angle is equal to aconstant multiplied by tools

a.

angle of inclinationb. normal rake anglec. velocity rake angled. effective rake angle

24. Swiss type screw machines havea. turretsb. radial slidesc. spindle carriersd. tool posts

25. Match List I (Name of the CastingProcess) with List II (Process Definition)and select the correct answer using thecodes given below:List IA. Die castingB. Electroslag castingC. Centrifugal castingD. Precision castingList II1. This process involves use of a mould

made of dried silica sand and phenolicresin mixture


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4 of 142. In this process, molten metal is forced

by pressure into a metal mould3. This process employs a consumable

electrode4. This process involves rotating a mould

while the metal solidifies5. This process produces very smooth,

highly accurate castings from bothferrous and non-ferrous alloys

Codes;A B C D

a. 5 4 1 2b. 2 3 4 5c. 5 3 4 2d. 2 4 1 5

26. Match List I (Casting Defects) with List II(Explanation) and select the correct answerusing the codes given below:List I

A. Metallic projectionsB. CavitiesC. InclusionsD. DiscontinuitiesList II1. Consist of rounded or rough internal or

exposed cavities including blow holesand pin holes

2. Formed during melting, solidificationand moulding

3. Includes single folds, laps, scars

adhering sand layers and oxide scale4. Include cracks, cold or hot tearing andcold shuts

5. Consist of fins, flash or massiveprojections and rough surfaces

Codes;A B C D

a. 5 4 1 2b. 2 3 4 5c. 5 3 4 2d. 2 4 1 5

27. Which of the following are produced byslush castinga. Hollow castings with thick wallsb. Hollow castings with thin wasc. Thin castingsd. Thick castings

28. A liquid jet issues from a nozzle inclinedat an angle of 60 to the horizontal and isdirected upwards. If the velocity of the jetat the nozzle is 18 m/s, what shallapproximately be the maximum vertical

distance attained by the jet from the pointof exit of the nozzle?a. 4.2 mb. 12.4 mc. 14.3 md. 16.5 m

29. A bullet enters a plank of 30 mm thickness

with a velocity of 100 m/s and emerges outfrom the plank with a velocity of 50 m/s.What is the minimum thickness of theplank so that the bullet remains embeddedin the plank?a. 100 mmb. 80 mmc. 60 mmd. 40 mm

30. What is the work done if a bucket of waterweighing 10 N is pulled up from a well 20m deep by a rope weighing 1 N/m?

a. 200 N-mb. 400 N-mc. 500 N-md. 600 N-m

31. Which one of the following statements iscorrect?The work done in stretching an elasticstring variesa. as the square of the extensionb. as the square root of the extensionc. linearly with the extension

d.

as the cube root of the extension32. Which one of the following statements istrue for effective temperature, ET?a. ET increases with increase in level of

activity and it decreases with increasein air velocity

b. ET decreases with increase in level of activity and it increases with increasein air velocity

c. ET increases with increase in level of activity and it increases with increasein air velocity

d. ET decreases with increase in level of activity and decreases with increase inair velocity

33. A train of weight 200 10 4 N is runningon a horizontal track at a constant speed of 10 m/s, overcoming a constant frictionalforce of 20 10 3 N. What is the power of the engine driving the train?a. 800 kWb. 1200 kWc. 200 kW


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5 of 14d. 400 kW

34. Match List I (Types of Tests andMaterials) with List II (Types of Fractures)and select the correct answer using thecodes given below:List IA. Tensile test on CI

B.

Torsion test on MSC. Tensile test on MSD. Torsion test on CIList II1. Plain fracture on a transverse plane2. Granular helecoidal fracture3. Plain granular at 45 to the axis4. Cup and cone5. Granular fracture on a transverse planeCodes;

A B C Da. 4 2 3 1b. 5 1 4 2c. 4 1 3 2d. 5 2 4 1

35. Which one of the following is the correctdefinition of critical ratio in scheduling?a. Demand time/supply lead timeb. Supply lead time/demand timec. Demand time/manufacturing lead timed. Manufacturing lead time/demand time

36. What is the discharge for laminar flowthrough a pipe of diameter 40 mm having

centre-line velocity of 1.5 m/s?a. 33 /

59m s

b. 33 / 2,500

m s

c. 33 / 5,000

m s

d. 33 / 10,000

m s

37. Which one of the following is theexpression for momentum thickness of aboundary layer?

a. 00

1U

dyU

=

b. 2

00

1U

dyU

=

c. 0 00

1U U

dyU U

=

d. 2

0 00

1U U

dyU U

=

38. The displacement thickness at a section,

for an air stream ( = 1.2 kg/m 3) movingwith a velocity of 10 m/s over a flat plateis 0.5 mm. What is the loss of mass rate of flow of air due to boundary layerformation in kg per meter width of plateper second?a. 36 10 b. 56 10 c. 33 10 d. 32 10

39. In a simple impulse turbine, the nozzleangle at the entrance is 30. What is theblade-speed ratio (u/V) for maximumdiagram efficiency?a. 0.25b. 0.5c. 0 433d. 0.866

40. Which of the following are fertilematerials?a. U233 and Pu 239 b. U238 and Th 239 c. U238 and Th 232 d. U235 and Th 236

41. A simple supported beam of length l issubjected to a symmetrical uniformly

varying load with zero intensity at the endsand intensity w (load per unit length) at themid span. What is the maximum bendingmoment?a. 3w l2 /8b. wl2 /12c. w l2 /24d. 5w l2 /12

42. Which one of the following correctlyexpresses the specific speed of a turbineand a pump, respectively?

a. 3/4 5/4, N Q N P H H

b. 3/4 5/4,N Q N P

H H

c. 5/4 3/4,N Q N P

H H

d. 7/4 3/4,N Q N P

H H

43. In a laminar boundary layer over a flatplate, what would be the ratio of wall shearstress 1 and 2 at the two sections which


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6 of 14lie at distances x 1 = 30 cm and x 2 = 90 cmfrom the leading edge of the plate?a. 1 / 2 = 3.0b. 1 / 2 = 1/3c. 1 / 2 = (3.0) 1/2 d. 1 / 2 = (3.0) 1/3

44. Total enthalpy of stream at the inlet of a

nozzle is 2800 kJ while static enthalpy atthe exit is 2555 kJ. What is the steamvelocity at the exit if expansion isisentropic?a. 70 m/sb. 245 m/sc. 450 m/sd. 700 m/s

45.

The above figure shows characteristics of three centrifugal pumps A, B and C. If E =Efficiency, H = Head and P = Power, thenA, B and C respectively represent whichone of the following 7a. E, P, H

b.

P, E, Hc. P, H, Ed. H, P, E

46. Which one of the following is representedby the area of the S.F. diagram from oneend upto a given location on the beam?a. B.M. at the locationb. Load at the locationc. Slope at the locationd. Deflection at the location

47.

What is the thrust at the point A in lamppost shown in the figure?a. 0.866 kNb. 0.5 kNc. 1.366 kN

d. 1 kN48. Given that the, principal stresses 1 > 2 >

3 and e is the elastic limit stress insimple tension; which one of the followingmust be satisfied such that the elasticfailure does not occur in accordance withthe maximum principal strain theory?

a. 31 2e E E E E <

b. 31 2e E E E E

>

c. 31 2e E E E E

> + +

d. 31 2e E E E E

< + +

49. Which of the following is caused by theoccurrence of a normal shock in thediverging section of a convergentdivergent nozzle?1. Velocity jump2. Pressure jump3. Velocity drop4. Pressure dropSelect the correct answer using the codesgiven belowa. 1 onlyb. 1 and 2c. 2 and 3d. 1 and 4

50.

Velocity diagram shown above is for animpulse turbine stage. What are thetangential force and axial thrust per kg/s of steam, respectively?a. 450 N, 8 Nb. 560 N, 8 Nc. 680 N, 4 Nd. 910 N, 4 N

51. Which one of the following is the purposeof blow- down in a boiler?a. To control drum levelb. To control solid concentration in the

boiler waterc. To increase the steam temperatured. To lower the steam temperature


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7 of 1452. For which one of the following columns,

Euler buckling load =2

2

4?

EI l

a. Column with both hinged endsb. Column with one end fixed and other

end freec. Column with both ends fixed

d. Column with one end fixed and otherhinged53.

What is the value of K for which therelative damping of the closed loop systemshown above is equal to 0.5?

a. 2b. 3c. 4d. 5

54. Match List I (Mohrs Circles of Stress)with List II (Types of Loading) and selectthe correct answer using the codes givenbelow:A. List I

List II1. A shaft compressed all-round by a hub2. Bending moment applied at the free

end of a cantilever3. Shaft under torsion4. Thin cylinder under internal pressure5. Thin spherical shell under internal

pressureCodes;

A B C D

a. 5 4 3 2b. 2 4 1 3c. 4 3 2 5d. 2 3 1 5

55. A horizontal beam under bending has amaximum bending stress of 100 MPa anda maximum shear stress of 20 MPa. What

is the maximum principal stress in thebeam?a. 20b. 50c. 50 + 2900 d. 100

56. Consider the following statements for asimply supported beam subjected to acouple at its mid-span?1. Bending moment is zero at the ends

and maximum at the centre2. Bending moment is constant over the

entire length of the beam3. Shear force is constant over the entire

length of the beam4. Shear force is zero over the entire

length of the beam.Which of the statements given above arecorrect?a. 1, 3 and 4b. 2, 3 and 4c. 1 and 3d. 2 and 4

57. Which one of the following weldingprocesses consists of smaller HeatAffected Zone (HAZ)?a. Arc weldingb. Electron beam weldingc. MIG weldingd. Thermit welding

58. In which of the following operations,micro motion study technique is used?1. Short cycle operations lasting two

minutes or less2. Long cycle operations lasting more

than five minutes3. Medium cycle operations lasting

between two and five minutesSelect the correct answer using the codesgiven belowa. 1 onlyb. 1 and 2c. 2 and 3d. 1, 2 and 3

59. The following are the constituent steps inthe process of powder metallurgy


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8 of 141. Powder conditioning2. Sintering3. Production of metallic powder4. Pressing or compacting into the desired

shapeIdentify the correct order in which theyhave to be performed and select the correct

answer using the codes given belowa. 1, 2, 3, 4b. 3, 1, 4, 2c. 2, 4, 1, 3d. 4, 3, 2, 1

60. A cutter breaks while cutting gears and isremoved by the operator. Which of thefollowing represents this activity on theflow process chart?a. Delay Db. Operation Oc. Operation cum transportation Od. Inspection

61. Which of the following are thecharacteristics of the injection moulding of plastics?1. It is the most economical method of

mass producing a single item2. In most cases finished products are

obtained3. There is lot of waste of thermoplastic

since the runners and sprues can not bereused

Select the correct answer by using thefollowing codesa. 1 and 2b. 2 and 3c. 1 and 3d. 1, 2 and 3

62. Gear shaping is a process of manufacturing gears.Which one of the following principles isemployed by it?a. Font cutting with cutterb. Generating tooth form with a

reciprocating cutterc. Generating tooth form by a rotating

cutterd. Generating form with a reciprocating

and revolving cutter63. Match List I (Name of the Process) with

List II (Advantage) and select the correctanswer using the codes:List IA. Sand castingB. Ceramicmold casting

C. Die castingD. Centrifugal castingList II1. Large cylindrical parts with good

quality2. Excellent dimensional accuracy and

surface finish

3.

Intricate shapes and close toleranceparts4. Almost any metal is cast and there is

no limit to size, shape and weight5. Good dimensional accuracy, finish and

low porosityCodes

A B C Da. 2 3 5 1b. 4 1 2 3c. 2 1 5 3d. 4 3 2 1

64. Match List I with List II and select thecorrect answer using the codes givenbelow:List IA. Bottle filling of gasB. Nernst Simon statementC. Joule Thomson effectD. P dvList II1. Absolute zero temperature2. Variable flow

3. Quasistatic path4. Isenthalpic process5. Dissipative effect6. Low grade energy7. Process and temperature during phase

changeCodes;

A B C Da. 6 5 4 3b. 2 1 4 3c. 2 5 7 4d. 6 1 7 4

65. M1 kg of water at T 1 is isobaric ally andadiabatically mixed with M 2 kg of water atT2(T1 > T 2). The entropy change of theuniverse isa. Necessarily positiveb. Necessarily negativec. Always zerod. Negative or positive but not zero

66. A heat engine using lake water at 12C assource and the surrounding atmosphere at2C as sink executes 1080 cycles per mm.


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9 of 14If amount of heat supplied per cycle is 57J, what is the output of the engine?a. 66Wb. 56Wc. 46Wd. 36W

67. A reversible heat engine runs between

high temperatures T 1 arid lowtemperatures T 2. The work output of thisheat engine is used to run a reversiblerefrigeration cycle absorbing heat attemperature T 3 and rejecting attemperature T 2. What is the COP of thecombined system?

a. 31 21 2 3

T T T T T T

b. 2 321 2 3

T T T T T T

c. 311 2 2 3

T T T T T T

d. 3 11 3 2 1

T T T T T T

68. Match List I with List II and select thecorrect answer using the codes givenbelow:List IA. Reversible cycleB. Mechanical work C. Zeroth LawD. HeatList II1. Measurement of temperature2. Clapeyron equation3. Clausius Theorem4. High grade energy5. 3rd Law of thermodynamics6. Inexact differentialCodes;

A B C Da. 3 4 1 6b. 2 6 1 3c. 3 1 5 6d. 1 4 5 2

69. When a refrigeration plant is started, theevaporator temperature decreases fromroom temperature to the required value.During this period, how does thecompressor power requirement vary?a. It increases continuouslyb. It decreases and then becomes constant

c. It increases, reaches a peak and thendecreases

d. It remains constant70. To meet short range changes in demand of

a product, which of the followingstrategies can be considered?1. Overtime

2.

Subcontracting3. Building up inventory4. New investmentsSelect the correct answer from the codesgiven belowa. 1, 2 and 3b. 1, 3 and 4c. 2 and 3d. 1 and 2

71.

In the T-S diagram shown in the figure,which one of the following is representedby the area under the curve?a. Total work done during the processb. Total heat absorbed during the process

c. Total heat rejected during the processd. Degree of irreversibility72. A refrigerating machine working on

reversed Carnot cycle takes out 2 kW of heat from the system at 200 K whileworking between temperature limits of 300K and 200 K. COP. and power consumedby the cycle will, respectively, bea. 1 and 1 kWb. 1 and 2 kWc. 2 and 1 kWd. 2 and 2 kW

73. If a gas obeys van der Waals equation atthe critical point, then what does RTIPVequal to?a. zerob. unityc. 1.50d. 2.67

74. In a simple gas turbine power plantoperating on standard Brayton cycle powerneeded to drive the compressor is 175 kW,rate of heat supplied during constant


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10 of 14pressure heat addition process is 675 kW.Turbine output obtained during expansionis 425 kW. What is the rate of heatrejection during constant pressure heatrejection?a. 75 kWb. 425 kWc. 500 kWd. 925 kW

75. What is the efficiency of an idealregenerative Rankine cycle power plantusing saturated steam at 327C andpressure 135 bar at the inlet to the turbine,and condensing temperature of 27C(corresponding saturation pressure of 3.6kPa)?a. 92%b. 33%c. 50%d. 42%

76. Which of the following can be solved bythe Brown and Gibson procedure?a. Transportation problemb. CPM network c. Site location problemd. Product-mix problem

77. Consider the following1. Simplified production planning and

control systems2. Reduced material handling3. Flexibility of equipment and personnelThe advantages of flow-line layout in amanufacturing operation area. 1, 2 and 3b. 1 and 2c. 2 and 3d. 1 and 3

78. Several sequencing rules can be used tosequence jobs. The performance of theserules can be studied using severalperformance measures. Consider thefollowing sequencing rules

SPT (Shortest Processing Time)EDD (Expected Due Date)and the following performance measuresMFT (Mean Flow Time)ML (Mean Lateness)Which one of the following is not correct?a. SPT minimizes MFTb. EDD minimizes MFTc. EDD minimizes MLd. SPT minimizes ML

79. Which of the flowing factors necessitate achange in schedule?1. Change in Board of Directors2. Capacity modification3. Lack of capital4. Change in priority5. Unexpected rush orders

Select the correct answer using the codesgiven belowa. 2, 3 and 4b. 1, 2 and 5c. 2, 4 and 5d. 1, 3 and 4

80. For economic manufacture, the total

annual cost is given 3s 12 MD

PQ

+

;

whereM is number of parts made per month

P is processing cost per partWhich one of the following is representedby DIQ in the above expression?a. Setting up costb. Profit per partc. Bonusd. Setting up cost/part

81. Match List I with List II and select thecorrect answer using the codes givenbelow the lists:List I (Type of Chart)A. Outline process chartB. Multiple Activity chartC. SIMO chartD. Non-machine chartList II (Definition)1. It is used to record the activities of one

subject in relation to one or moreothers

2. It is a chart in which activities of themachine or machines are recorded inrelation to that of the operator

3. It records the main activities of the

process through the symbols of operation and inspection4. It is used to record the activities of the

hands of an operator5. It makes use of Therblig for charting

minute elements of an operationCodes;

A B C Da. 3 2 5 1b. 5 1 4 2c. 3 1 5 2


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11 of 14d. 5 2 4 1

82. Profit volume chart technique is aneffective tool of application for analysiswhen the Company is dealing witha. one product onlyb. a loss situationc. only turn-key assignments

d.

more than one product83. Standard material cost of a product is Rs.20/- @ Rs. 10 per kg. In one batch, on anaverage the consumption of material was1.8 kg and rate of material was Rs. 12 perkg. What is the material usage variance?a. Rs. 2/- adverseb. Rs. 2/- favorablec. Rs. 2.40 favorabled. Rs. 1 .60 adverse

84. Assertion (A) Angle of twist per unitlength of a uniform diameter shaft depends

upon its torsional rigidity.Reason (R): The shafts are subjected totorque only.a. Both A and R are individually true and

R is the correct explanation of Ab. Both A and R are individually true but

R is not the correct explanation of Ac. A is true but R is falsed. A is false but R is true

85. Assertion (A): Francis turbine may be usedas prime mover for hydraulic power plantwhen the head available is around 300 m.Reason (R): Francis turbine is a reactionturbine.a. Both A and R are individually true and



86. Assertion (A): For high head and low-discharge hydraulic power plant, Peltonwheel is used as prime mover.

Reason (R): The non-dimensional specificspeed of Pelton wheel at designed speed ishigh.a. Both A and R are individually true and



87. Assertion (A): A beam subjected only toend moments will be free from shearingforce.Reason (R): The bending momentvariation along the beam length is zero.a. Both A and R are individually true and



88. Assertion (A): Uniaxial stress normallygives rise to triaxial strain.Reason (R) Magnitude of strains in theperpendicular directions of applied stressis smaller than that in the direction of applied stress.a. Both A and R are individually true and

R is the correct explanation of A

b. Both A and R are individually true butR is not the correct explanation of A

c. A is true but R is falsed. A is false but R is true

89. Assertion (A): Spiral bevel gears designedto be used with an offset in their shafts arecalled Hypoid gears.Reason (R): The pitch surfaces of suchgears are hyperboloids of revolution.a. Both A and R are individually true and



90. Assertion (A): Hot working does notproduce strain hardening.Reason (R): Hot working is done abovethe recrystallization temperature.a. Both A and R are individually true and


R is not the correct explanation of A

c. A is true but R is falsed. A is false but R is true

91. Assertion (A): Rolling requires highfriction which increases forces and powerconsumption.Reason (R): To prevent damage to thesurface of the rolled products, lubricantsshould be used.a. Both A and R are individually true and

R is the correct explanation of A


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12 of 14b. Both A and R are individually true but


92. Assertion (A) Indirect extrusion operationcan be performed either by moving ram orby moving the container.

Reason (R): Advantage in indirectextrusion is less quantity of scrapcompared to direct extrusion.a. Both A and R are individually true and



93. Assertion (A): Power input per TR of arefrigeration system increases withdecrease in evaporator temperature.

Reason (R): COP. of refrigeration systemdecreases with decrease in evaporatortemperature.a. Both A and R are individually true and



94. Assertion (A): Coils of concentriccylindrical helical springs, used to providegreater spring force in a limited space, arewound in opposite directions.Reason (R): The winding of coils inopposite direction in case of concentricsprings prevents locking of two coilsduring misalignment or buckling.a. Both A and R are individually true and



95. Assertion (A): When the pressure ratio(p2 /p1) in a nozzle reaches critical pressureratio, the discharge becomes zero.Reason (R): The nozzle gets choked.a. Both A and R are individually true and



96. Which one of the following is true for thelast few teeth of a broach which are meantfor fine finishing?a. They have equal diameterb. They have increasing diameterc. They have decreasing diameterd. They have alternately increasing and

decreasing diameter97. The size effect refers to the increase inspecific cutting energy at low values of unreformed chip thickness. It is due towhich one of the following?a. Existence of ploughing forceb. Work hardeningc. High strain rated. Presence of high friction at chip-tool

interface98. Which one of the following gating systems

is best suited to obtain directional

solidification?a. Top gratingb. Part-line gratingc. Bottom gratingd. Stepped grating

99. Which one of the following is the purposeof a surge tank in a Pelton turbine station?a. It acts as a temporary storage during

load changesb. It prevents hydraulic jumpc. It prevents surges at the transformer

d.

It prevents water hammer due tosudden reduction in load100. 100. A log of length 20 m, diameter 2 m

and specific weight 500 N/m 3 rests on alevel ground. What is the work done (inNm) to make it to stand vertical?a. (12) (200) (50) (20)b. (12) (200) (50) (10)c. (12) (200) (50) (9)d. (12) (200) (50) (8)

101. Which one of the following helps inavoiding cavitations in centrifugal pumps?a. Low suction pressureb. High delivery pressurec. Low delivery pressured. High suction pressure

102. 102. Consider the following statementswith regard to the specific speeds of different types of turbine1. High specific speed implies that it is a

Pelton wheel2. Medium specific speed implies that it

is an axial flow turbine


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13 of 143. Low specific speed implies that it is a

Francis turbineWhich of these statements given aboveis/are correct?a. 1 onlyb. 2 onlyc. 3 only

d.

None103. A circular plate of 1.5 m diameter issubmerged in water with its greatest andleast depths below the water surface being2 m and 0.75 m respectively. What is theapproximate magnitude of the total thruston one face of the plate?a. 24 kNb. 28 kNc. 12 kNd. 16 kN

104. Which one of the following statements iscorrect?A steady flow of diverging straight streamlinesa. is a uniform flow with local

accelerationb. has convective normal accelerationc. has convective tangential accelerationd. has both convective normal and

tangential accelerations105. Which one of the following is the

expression of the rotational component fora two-dimensional fluid element in x-yplane?

a. 12 z

v u x y

=

b. 12 z

v u x y

= +

c. 12 z

u v x y

=

d. 12 z

u v x y

= +

106. What is the percentage error in theestimation of the discharge due to an errorof 2% in the measurement of the readingof a differential connected to an orificemeter?a. 4b. 3c. 2d. 1

107. Which one of the following is thecharacteristic of a fully developed laminarflow?a. The pressure drop in the flow direction

is zerob. The velocity profile changes uniformly

in the flow directionc. The velocity profile does not change in

the flow directiond. The Reynolds number for the flow is

critical108. Which one of the following is the correct

relation between the boundary layerthickness displacement thickness * andthe momentum thickness ?a. > * > b. * > > * c. > > * d. > * >

109. The thickness of turbulent boundary layerat a distance x from the leading edge on aflat plate varies asa. x4/5 b. x3/5 c. x1/2 d. x1/5

110. When a flat plate of 0.1 m 2 area is pulledat a constant velocity of 30 cm/s parallel toanother stationery plate located at adistance 0.01 cm from it and the space in

between is filled with a fluid of dynamicviscosity = 0.001 Ns/m 2, the force requiredto be applied isa. 0.3 Nb. 3 Nc. 10 Nd. 16 N

111. Which one of the following is thecontinuity equation in differential form?(The symbols have usual meanings)

a. dA dV d A V

+ + =constant

b. dA dV d A V

+ + =0

c. A V dA dV d

+ + =constant

d. 0 AdA VdV d + + = 112. In on-off control refrigeration system,

which one of the following expansiondevices is used ?a. Capillary tubeb. Thermostat


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14 of 14c. Automatic expansion valved. Float valve

113. When does L.P. cut-off occur in arefrigeration system?a. If the ambient temperature is lowb. If non-condensable gases are present in

the condenser

c.

If refrigerant charge is owld. If lubricating oil gets accumulated inthe condenser

114. Moist air exists at a pressure of 1.01 bar.The partial pressure and saturationpressure of water vapour are 0.01 bar and0.02 bar respectively. What are the relativehumidity and humidity ratio of the moistair, respectively?a. 50% and 0.00622b. 100%and0.0126c. 50% and 0.01 26d. 100% and 0.00622

115. In order to cool and dehumidify a streamof moist air, it must be passed over a coilat a temperaturea. which lies between the dry bulb and

wet bulb temperatures of the incomingstream

b. which lies between the wet bulb anddew point temperatures of theincoming stream

c. which is lower than the dew pointtemperature of the incoming stream

d. of adiabatic saturation of incomingstream

116. Which of the featuresd of expansionvalves in the following lists are correctlymatched?Expansion Device Feature1. Capillary tube : Choking2. Thermostatic expansion valve :

Constant temperature3. Automatic Expansion valve : Constatn

degree of superheat

4. Float valve : Mass flow rate of refrigerant is proportional to loadSelect the correct answer using the codesgiven belowa. 1 and 2b. 1 and 3c. 1 and 4d. 3 and 4

117. If moist air is sensibly cooled above itsdew point, which of the followingstatements are correct?

1. Relative humidity decreases2. Wet bulb temperature decreases3. Wet bulb temperature increases4. Humidity ratio remains constantSelect the correct answer using the codesgiven belowa. 1 and 2

b.

1 and 3c. 3 and 4d. 2 and 4

118. Water in an insulative evaporative coolerevaporates at the rate of 0.003 kg/s. Airflow rate is 1 kg/s. What is the airtemperature decrease if the specific heat of humid air is 1 kJ/kg K and latent heat of water is 2500 kJ/kg?a. 2.5 Cb. 3.0 Cc. 75 Cd. 10 C

119. Match List I with List II and select thecorrect answer using the codes givenbelow:List IA. Sulphur candle testB. Halide torch testC. Soap and water testD. Ammonia swab testList II1. Propane

2.

Ammonia3. Halocarbon refrigerants4. Sulphur dioxideCodes;

A B C Da. 2 3 1 4b. 4 1 3 2c. 2 1 3 4d. 4 3 1 2

120. In a stop-watch time study, the observedtime was 0.16 minute; the performancerating factor was 125 on the 100 normal(percentage scale). What is the standardtime in minutes if 10% allowances arepermitted?a. 0.180b. 0.200c. 0.220d. 0.240

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i3619214IAS-Pre-Mechanical Engineering Previous Paper 2004