Company: Indian Space Research Organisation

Written Test for Scientist / Engineer_SC : [ Mechanical Engineering ]

Date: 09-12-2010 , Place: Hyderabad.

Question Pattern for Written Examination
Ø 80 Questions
Ø 2.00 hrs Duration
Ø ¼ Negative Marks
Ø All are Objective & Multiple choice Questions.

1. The concept of ———————————- derived from the “ZEROTH LAW OF
THERMODYNAMICS”.
TEMPERATURE

2. The concept of ————————————- derived from the “SECOND LAW OF
THERMODYNAMICS”.
ENTROPY

3. The expression for isentropic index [?] in terms of number of degrees of freedom
( n ) ————————
1+ [ 2 / n]

4. The critical Reynolds no upto which the viscous flow exists in pipe ——————-
2000

5. Two forces of equal magnitude P acts at right angles to each other and having same directions.
Find out the expression for their resultant [R ]——————–
[2]½ P

6. The angular frequency of handclock——————
?/30 rad/s

7. The equation for free torsional vibration—————————-
[1/2?] [q/I]½

8. A thin cylinder is subjected to longitudinal stress s0 and internal pressure P , findout the maximum
shearstress developed in it [ q max] ————————
0.5 s0

9. Rate of moment of momentum is equal to the ————————-
Torque applied by the body

10. The expression for loss of energy [he ] due to sudden enlargement of the pipe——–
he =[v1-
v2]²/2g

11. A spring of stiffness K is divided into “n” number of springs. Each spring having stiffness
—————————
nK

12. The non-dimensional number corresponds to
[inertia forcecompressibility
force]½—————————— Euler number

13. Equation for forced vortex flow—————————–
v/r = constant

14. The causes of cavitation
Metallic surfaces are damaged
Noise & vibrations

15. How to increase the thermal efficiency in Carnot cycle by——————————-
Decreasing low temperature

16. The slenderness ratio in columns can be obtained from the —————
Least radius of gyration

17. 50:1 gear reduction ratio possible in—————–
worm gear

18. Wire drawing property named as ————————-
ductility

19. One man is standing in the elevator and the elevator is moving in the upward direction. What type
of reading regarding the weight of man will we get from gauge—————
The weight of man shown by the gauge will more the actual weight
of the man.

20. LMTD for counterflow heat exchanger is compared to parallel to heat exchanger—–
More

21. The free damping equation 2yºº + 3yº +8y =0. Calculate damping factor (D.F )——–
3/8

22. The discharges for the two parallel pipes of same lengths are Q1 & Q2 respectively and their
diameters are 200 mm & 800 mm respectively. Calculate the ratio of discharge of smaller pipe to
larger pipe.
1/32

23. A compressor is used to compress the air from 5 bar to 10 bar .Calculate its critical pressure [ P
?]———————-
2.64 bar

24. Equivalent twisting moment——————————
Te = [T² + M²]½

25. The shear stress distribution in pipe flow —————————–
Centre is zero and linearly varying from the center to
the wall

26. The irrational component in x-y is————–
dv/dx = du/dy

27. The ratio kinetic viscosity/thermal diffusivity is ————-
Nusselt Number

28. The cylinder is subjected to insulations K & 2K at the outside surface to avoid heat transfer. In
order to arrest heat transfer effectively , which insulation should be provided first at the outer surface?
2K & K respectively

29. The maximum amplitude in this vibration equation y = 6 sin?t ——–
6

30. The thermal boundary layer in an ideal fluid flow is ————–
0

31. What does tend to stagnation point ———————–
The velocity is 0 at the stagnation point due to the increase in
pressure energy from the conversion of K.E into P.E.

32. Match the following:
i. subsonic nozzle : figure
ii. Supersonic nozzle : figure
iii. Subsonic diffuser : figure
iv. Centrifugal compressor : figure

33. The factor of safety subjected to number of cycles related to
Endurance limit

34. In composite beam , width is directly proportional to ———————————–
if the depth of the beam is kept constant.
a M

35. The heat transfer rate of hollow cylinder is inversly proportional to the following
——————————— r2/r1

36. A material at 300ºC is immersed in water at 30ºC such that it will take 170 seconds to become
150ºC .
A same material at 300ºC is put in air at 30ºC but it will take 200 seconds to become 150ºC. What is
the reason behind it ?
K of water is more compared to air

37. Radiation is —————————————— wave phenomenon
Electromagnetic without medium

38. The compression ratio[r] of petrol engine ranges from ——————-
6 to 10

39. ?dQ/T =0 and ?s=0 corresponds to —- irreversible & adiabatic

40. Cold working of metal increases ———————-
Tensile strength

41. The power absorbed in belt drive depends on———————–
Tension in tight side, Tension in slack side, coefficient of friction &
Radius of pulley.

42. The temperature loss related ————– hysteresis loss

43. The convergent pipe having entry and exit diameters are 100 and 50 mm respectively, find out
their velocity ratio from entry to exit…………..
1/4

44. They had given one composite circular pipe having 4 varying cross sections . They are 2D, 1.5D,
4D & D respectively. The water is entering at velocity V at section 1 and leaving at section 4. Find out
the pressure decreasing order……………
P4>P2>P1>P3

45. The bulb having weight 150N supported by two ropes and attached to the walls having angles 45º
& 60º. Findout the reaction forces in the ropes ?
This is related to Lamis theorem

46. A hollow sphere of radius r . A particle is moving with coefficient of friction 1/[3]½ inside the
sphere from wall . which height will it become rest?

47. The disc is resting on the rough wall by a rope tied at the center . The rope makes angle with the
wall around 30º. The tension in the string is ———-than the weight of the disc.
more

48. A railway wagon containing partially full of water. Which angle—————-

49. Findout the graph between discharge [Q] in the x-axis and head [H] in the yaxis———-

50. In welding pitch dimension is limited to———————-

51. The composition of inconel alloy——————-

52. There is a heat transfer between two walls having thickness and conductivities k1 & K2
respectively. The linear temperature profile of first wall is more steeper than the second wall . Findout
the ratio K1/K2 ———————
a) >0 b) <0 c)=0 d) the given data is insufficient 53. The max shear stress developed in solid circular shaet is 100 MPa . Calculate the max normal stress developed in it? ?????? 54. This question related to welding ------------- 55. Bearing liner------------------------- a) Babbit metal b) Gun metal 56. Electrical resistance material --------------Nichrome 57. This question related to radiation 58. A sun emits 1150K at 0.5µ. A furnace emits 300k from small door -------------- 59. In the simple pendulum , the maximum amplitude depends on ------------------- increase in length 60. The fuel flow increases if------------------------- a) exhaust valve burnt b) filter choke c) silencer choke 61. The jet propulsion depends on------------- a) jet velocity b) weight ratio 62. What is the condition for perfect frame------------------------------------- 63. Depth of cut can be increased by----------------------- 64. The workpiece can be held in----------------- 65. This is related toNucleate boiling 66. What is the expression for Reynolds number in terms of diameter of the pipe…………..Re =?VD/ µ 67. Air conditioning means--------------- a) cooling & heating b)dehumidifying c) removing impurities from air d)all 68. Fibrous fracture occurs in ------------------------ a)brittle fracture b) ductile fracture c)shear fracture d)none 69. In laser beam machining , the workpiece should be-------------- a)absorbed by all the rays b) reflected by all the rays 70. Foam and coke are good insulators. Why?----------------------- a)less density b) 71. Gold property------------------ a)good conductor b)good insulator 72. In lathe , the workpiece can be held in -------------------------------------- a) live center b)steady rest c)3-way chuck d)4-way chuck 73. The wall having conductivities K1 K2 Findout the equivalent conductivity of the material--------------------? INTERVIEW PATTERN I. Project Explanation II. Fluid Mechanics: i. Define laminar flow & Turbulent flow ii. What is the value of Reynolds no in pipe flow iii. What is the significance of Reynolds no iv. Head losses in pipe v. Define boundary layer in pipe flow & thickness of boundary layer vi. What is the variation of d in laminar & turbulent flow III. Strength of materials i. Draw the figure for spring damper system ii. Differential equation for spring damper system iii. Find out the deflection of spring damper system iv. Define stiffness and unit of stiffness IV. Material Science i. Ferrous materials ii. Non-ferrous materials iii. Define fatigue iv. Define fatigue resistance? v. Curve for fatigue vi. Fatigue limit