Can you please share the previous year question papers for DRDO Mechanical Engineering???

As per your request, here I am sharing the previous year question papers for DRDO Mechanical Engineering

1. A hydraulic press has a ram of 15 cm diameter and plunger of 1.5 cm.

It is required to lift a mass of 1000kg. The force required on plunger is

nearly equal to

a) 100N b) 1000N c) 10000N d) 1ON Ans.

2. If the stream function is given by Ψ= 3xy, then the velocity at a point

(2, 3) will be

a) 7.21 unit b) 18 unit c)10.82 unit d)54unit Ans.

3. The correct sequence of the centrifugal, pump components through

which the fluid flows is

a) Impeller, Suction pipe, Foot valve and strainer, Delivery pipe b) Foot valve and strainer, Suction pipe, Impeller, Deliverypipe c) Impeller, Suction pipe,Delivery pipe,Foot valve and strainer d) Suction pipe, Delivery pipe, Impeller,Foot valve and strainer Ans.

4. The relation p = constant, where y is the ratio of the specific heats of

ideal gas, is applicable to

a) Any adiabatic process b)Only reversible adiabatic process c) Only irreversible adiabatic process d) Only isothermal process Ans.

5. Across a normal shock

a) static pressure and the static temperature rise b) entropy remains constant c) velocity and static pressure decrease d) density and temperature decrease Ans.

6. A necessary precaution in selection of pumps for parallel operations is

that

a) H-Q characteristics of both should be identical b) Both pumps should be centrifugal type c) Both pumps should be identical d) There should not be change from positive to negative slope In H-Q curve Ans.

7. A metallic cube of side 10 cm, density 6.8 gm/cc is floating in liquid

mercury (density 13.6gm/cc), with 5 cm height of cube exposed above

the mercury level. Water (density 1 gm/cc) is filled over this, to

submerge the cube fully. The new height of cube exposed above mercury

level is

a) 4.6 cm b)5.4cm c) 5.0 cm d)5.8cm Ans.

8. The pressure drop for a relatively low Reynolds number flow in a 600

mm, 30 m long pipeline is 7OkPa. What is the wall shear stress?

a) 0 Pa b)1400 Pa c) 700 Pa d) 350 Pa Ans.

9. The radiative heat transfer rate per unit area (W/m2) between two

plane parallel grey surfaces (emissivity 0.9) maintained at 400 K and

300 K is (Stefan Boltzmann constant σ = 5.67 x 10 W/m2k4)

a) 1020 b)464 c)812 d)567 Ans.

10. At the eye tip of a centrifugal impeller, blade velocity is 200 m/s

while the uniform axial velocity at the inlet is 150 m/s. If the sonic

velocity is 300 m/s, then the inlet Mach number of the flow will be

a)0.75 b) 0.66 c) 0.90 d)0.83 Ans.

11. The transition Reynolds number for flow over a flat plate is 5* 105.

What is the distance from the leading edge at which transition will occur

for flow of water with a uniform velocity of 1 m/s? (For water. the

kinematic viscosity, v = 0.86* 10-6 m2/s)

a) 0.43m b) 1m c)43m d)103m Ans.

12. For a reciprocating water pump having cylinder dia d and crank

radius r, if W is the weight of water lifted, the coefficient of discharge is

a) 2 b) 2 2 c) 2 d) 2 Ans.

13. Both free vortex and forced vortex can be expressed mathematically

in terms of tangential velocity V at the corresponding radius r. Choose

the correct combination

Free vortex Forced vortex

a) V r xconst. Vr= const. b)V2x r = const. V = r x const. c)V x r = const. V2= r x const. d) V x r= const. V =r x const. Ans.

14. A bucket of water is hanging from a spring balance. An iron piece is

suspended into water without touching sides of bucket from another

support. The spring balance reading will

a)Remain same b)Decrease c) Increase d) Increase/decrease depending on depth of immersion Ans.

15. A single-stage impulse turbine with a diameter of 120 cm runs at

3000 rpm. If the blade speed ratio is 0.42 then, the inlet velocity of steam

will be

a) 79m/s b) 188m/s c) 450m/s d) 900m/s

Ans.

16. The critical point and triple point data for water are, Tc = 374°C, Pc =

22.1 Mpa, TT = 0.01°C. PT = 0.6 kPa Indicate the phase change that will

occur in following cases,

(i) ice at 0.5 kPa is heated isobarically

(ii) Water vapour at 400°C is compressed isothermally

a)(i)alongAB. (ii) alongCD b)(i)alongCD.(ii)along AB c) (i) alongOD.(ii) along

PR d) (i) along RD.(ii)alongOR Ans.

17. The ratio of specific heats of a gas is 1.4 and the value of specific heat

at constant pressure is 7.0 cal/mole° C. The difference between specific

heat at constant pressure and specific heat at constant volume will be (in

cal/mole° C)

a) 1.4 b) 1.7 c) 5.0 d) 2.0 Ans.

18. The coefficient of linear expansion of a solid is L. The volume V of a

cube of this solid on being heated by 1° C will change by a)VL b)3VL c)3L d)VL/3

Ans. 19. Two springs of equal length but having stiffness of 10 N/mm and 15

N/mm support a mass of 2 tonnes in series. Find the frequency of

vibration

a)12 √3Hz b)12 √10Hz c)12 √15Hz d)12 √2Hz Ans.

20. Ratio of pitch circle diameter in millimeters to the number of teeth, is

known as

a) Module b) Circular pitch c) Diametral pitch d) Clearance Ans.

21. Two particles with masses in the ratio 1:4 are moving with equal

kinetic energies. The magnitude of their linear momentums will conform

to the ratio

a)1:8 b) 1 :√2 c) √2:1 d)1:2 Ans.

22. Which of the following stresses are associated with the tightening of

a nut on a stud?

1. Tensile stresses due to stretching of stud

2. Bending stresses of stud

3. Transverse shear stresses across threads

4. Torsional shear stresses in threads due to frictional resistance

Select the correct answer using the codes given below:

a) 1,2 and 3 b) 1,2and 4 c) 1,3 and 4 d) 2,3 and 4 Ans.

23. A flywheel weighs kg and has a radius of gyration of 100 cm. It is

given a spin of 100 rpm about its horizontal axis. The whole assembly is

rotating about a vertical axis at 6 rad/sec. The gyroscopic couple

experienced will be

a)2,000 kgm b) 19,620 kgm c)20,000kgm d) 1,962kgm Ans.

24. Determine the diameter of solid shaft which will transmit 90kw at

160 rpm, if the shear stress in the shaft is limited to 60 N/mm2

a)50mm b)6Omm c)77mm d)7Omm Ans.

25. A roller of weight W is rolled over the wooden block shown in the

given figure. The pull required just to cause the said motion is

a) W/2 b)√3W c) W d) 2 W Ans.

26. For one-dimensional isentropic flow in. a diverging passage, if the

initial static pressure is P1, and the initial Mach number is M1 (M1 <1),

then for the downstream flow

a) M2< M1; P2

M1; P2>p1 c)M2p1 d)M2>M1; P2
27. In a furnace made of bricks,

Inside heat transfer coefficient 35 W/m2K

Outside heat transfer coefficient =25 W/m2K

Thermal conductivity of bricks (15 cm thick) = 0.15 W/mK

The overall heat transfer coefficient (in W/m2K) will be closer to the

a)Insideheat transfer coefficient b) Outside heat transfer coefficient c) Thermal conductivity of bricks d) Heat transfer coefficient based on the thermal conductivityof the bricks alone. Ans.

28. Two systems have the same wet bulb temperature of 200 C. System ‘A’

has Dry bulb temperature of 25°C since it has a relative humidity of 65%.

System ‘B’ has a relative humidity of 30%. What will be its dry bulb

temperature

a) 33°C b) 25°C c)27°C d) 22°C Ans.

29. Four rods with different radii r and length l are connected to two

reservoirs at different temperature. Which one of them will conduct

most heat?

a)r=2cm&l=2m b)r=lcm&l=1m c)r=2cm&l=½m d)r=½cm&l= ½m Ans. 30. A 1000 kg vehicle travelling at 80 m/s impacts a plunger attached to

a piston-cylinder arrangement. If all of the energy of the vehicle is

absorbed by the 20 kg of liquid contained in the cylinder, what is the

maximum temperature rise of the liquid? (The specific heat of the liquid

(I is 4.0 kJ/kg.°C) a)55°C b) 40°C c)45°C d)50°C Ans. 31. In the Van der Waal’s gas equation (ƿ+ )(v – b) = RT to constant ‘a’

is introduced to compensate for

a) Reductioninspecific volume b) Inter-molecular forces c) Reduction in specific heat d) All of the above Ans.

32. The centrifugal tension in belts

a) Increase power transmission upto certain speed and then decreases b) Increases power transmission c) Does not affectpowertransmission d) Reduces power transmission

Ans. 33. In nodular iron, graphite is in the form of a) Spheroids b) Nodular carbide c) Flakes d) Cementite Ans. 34. Corrosion resistance of steel increases by addition of a) Vanadium, aluminium b) Sulpher, phosphorus, lead c) Chromium and nickel d) Tugsten, molybdenum, vanadium, chromium Ans. 35. Phenomenon of progressive extension of material with time at

constant load is called a) Plasticity b) Creep c) Yield d) Breaking Ans. 36. Rivets are made of a) Soft material b) Ductile material c) Hard material d) Brittle material Ans. 37. Addition of copper to aluminium results in a) Precipitation hardening system b) Corrosion resistance c) Grain refinement d) High machinability Ans.

38. A Hooke’s joint is used to connect two

a) Coplanar & Nonparallel shafts b) Non coplanar & Nonparallel shafts c) Coplanar & Parallelshafts d) All the 3 above Ans. 39. In a hardness test, L is load in kg, D is diameter of ball in mm and d is

diameter of indentation in mm. Brincll Hardness Number is expressed

by the equation a) BIIN = ( − 2− 2 b)BIIN = 2 ( − 2− 2

c) BIIN = ( − 2− 2 d)BIIN = 2 ( − 2− 2 Ans.

40. Circumferential anti longitudinal strains in the cylindrical boiler

under internal steam pressure arc Є1 and Є2 respectively. Change in the

volume of the boiler cylinder per unit volume will be

a) Є12Є2 b) Є1Є22 c) 2Є1+ Є2 d) Є1+2Є2 Ans. 41. An overhung beam ABC of length 4m is supported at A and B 3m

apart. It is loaded with UDL of 5 kN/m along its entire length. Find the

value of load ‘P’ at C such that the reactions at A and B are equal and

opposite.

a)P10 kN b) P30kN c)P20kN d) P25kN

Ans. 42. If two gears have moment of inertias as I1 and 12 respectively and

mesh with a speed ratio ω2 / ω1 = n, then equivalent moment of inertia of

both gears referred to first one is

a)n2I1+I2 b)I1+ nI2 c)nI1+ I2 d)I1+n2I2 Ans.

43. A uniform circular ring of mass M and radius r is rotating with an

angular speed ω about an axis passing through its center and

perpendicular to the plane of the ring. Two identical beads, each of mass

m, somehow get attached at two diametrically opposite points. The

rotational speed of the ring will become

a) +2 b) + c) 2+2 d) ω Ans. 44. An electric lift is moving downward with an acceleration of g/3. the

vertical force between a passenger in the lift and its floor is equal to

a)3/4 of the passenger’s weight b) 2/3 of thepassenger’s weight c) Passenger’s weight d) 4/3 of thepassenger’s weight Ans. 45. A body of mass 10kg moving with a velocity of 1 m/s is acted upon by

a force of 50 N for two seconds. The final velocity of the body is

a) 22 m/sec b) 1m/sec c)√21m/sec d) 11 m/sec Ans.

46. Proof resilience may be defined as

a) Work done in strainingthe material b) Max. strain energy that can be storedin a material per unit volume c) Max. strain energy that can be storedina material under elastic condition d) Max. load which can be applied to amember Ans. 47. A plane intersects the co-ordinate axes at x = 2/3, y = 1/3, z = 1/2.

What is the Miller index of this plane?

a)(932) b)(432) c)(364) d)(423) Ans.

48. Relationship between modulus of elasticity E, modulus of rigidity G

and Poisson’s ratio μ is

a) G = E/2 (1 +μ) b) G=E (2-μ) c) E= G (1+μ) d) G=E/1+μ Ans.

49. A bar of Length L, area A and Young’s modulus E is subjected to a

pulling force P. The strain energy stored in the bar is

a) 2 b) 2 2 c) 2 2 d) 2

Ans.

50. What is the expression for crippling load for a column of length L,

with one end fixed and other end free?

a)P = π2EI/4L2 b)P=π2EI/L2 c)P=2π2EI/L d) 4π2El/L2 Ans.

51. A Mohr’s circle reduces to a point when the body is subjected to

a) Pure shear b) Uniaxial stress only c) Equal & opposite axial stresses on two mutually perpendicular planes, the planes being free of shear. d) Equal axial stresses are on two mutually perpendicular planes, the planes being free of shear. Ans.

52. Power screws are used to convert

a) Linear motion torotary motion b) None of these c) Both a & b d) Rotary motion intotranslatorymotion Ans. 53. Following gases are used in tungsten inert gas welding

a) CO2andll2 b)Argon and neon c) Argon and helium d) Helium and neon Ans.

54. The force required to punch a 25 mm hole in a mild steel plate 10

mm thick, when ultimate shear stress of the plate is 500 N/mm2 will be

nearly

a)78kN b) 393kN c) 98kN d) 158kN Ans.

55. One-half length of 50mm diameter steel rod is solid while the

remaining half is hollow having a bore of 5 mm. The rod is subjected to

equal and opposite torque at its ends. If the maximum shear stress in

solid portion is τ, the maximum shear stress in the hollow portion is: a)15 16 b) τ c)43

d)16 15 Ans. 56. Two metal plates of thickness ‘t’ & width ‘w’ arc joined by a fillet weld

of 450 as shown in fig. When subjected to a pulling force ‘F’ the stress

induced in the weld will be

a) b) 45 c) 45 d)2

Ans. 57. Ring rolling is used

a) To decrease the thickness and increase diameter b) To increase the thickness of a ring

c) For producing a seamless tube d) For producing large cylinder Ans.

58. A bar of 20mm dia is tested in tension. It is observed that when a load

of 38KN is applied the extension measured over a gauge length of

200mm is 0.12mm and contraction in diameter is 0.0036mm. Find the

Poisson’s ratio

a) 0.2 b) 0.3 c) 0.25 d) 0.33 Ans.

59. A perfect frame has N joints. The number of members should not be

less than

a) 2N-1 b) 2N-2 c) 2N-3 d) 2N-5 Ans.

60. A cantilever beam of rectangular cross section is subjected to load at

free end. If the depth of the beam is doubled and load is halved,

deflection of the free end as compared to original will be

a) 1/2 b) 1/8 c) 2 d) 1/16 Ans. 61. The kinematic planar chain Shown in the given figure is a

a) Structure b) Mechanism with 2 degreeof freedom c) Mechanism with 1degree of freedom d) Mechanism with more than 2 degree offreedom Ans.

62. The machining process in which the work piece is dissolved into an

electrolyte solution is called

a) Electro-chemical machining b) Ultrasonic machining c) Electro-discharge machining d) Laser machining Ans.

63. In the metal forming process, the stresses encountered are

a) Greater than yield strength but less than ultimate strength b) Less than yield strength of the material c) Greater than the ultimate strength of the material d) Less than the elastic limit Ans.

64. A grinding wheel is specified as 49 A 26 36 M 7 V 24. The number 36

stands for

a) Structure b) Grade c) Grit size d) Bond Ans.

65. In a fluid machinery, the relationship between saturation

temperature and pressure decides the process of

a) Flow separation b) Cavitation c) Turbulent mixing d) Water hammer Ans,.

66. Anodising is

a) A process of coating of zinc by hot dipping b) A zinc diffusion process c) A process used for makingthin phosphatecoatings on steel to act as a base orprimerfor enamels and paints d) An oxidizing process used for aluminiumand magnesium articles Ans.

67. The process layout is best suited where

a) Automation is employed b) Mass production is envisaged c) A few number of non-standardized unitsare to be produced d) Machines are arranged according tosequence of operation Ans. 68. The blank size of the gear of 3 mm module and 40 number of teeth is

a) 120mm b) 123 mm c)126 mm d)129 mm Ans.

69. A bag contains 7 white, 6 red and 9 black balls. Two balls are drawn

at random. The probability that both the balls will be black is a)111 b)12 77 c)577 d)977 Ans. 70. Match list—I (Machining Process) with list—II (Associated medium)

and select the correct answer using the codes given below the lists

List — I (Machining Process) List— II (Associated Medium)

A) Ultrasonic machining 1) kerosene

B) EDM 2) Abrasive slurry

C) ECM 3) Vacuum

D) FBM 4) Salt solution

A B C D a) 2 1 4 3 b) 2 3 4 1 c) 4 1 2 3 d) 4 3 2 1 Ans.

71. The rake angle of a cutting tool is 150, shear angle 45° and cutting

velocity 35 m/min. What is the velocity of chip along the tool face?

a)25.3m/min b)27.3m/min c)28.5m/min d)23.5m/min Ans.

72. The value of the determinant given below is 1 1 1 1+a 1 1 1 1 1 1 1 1 1−b 1 1 1+c a)–abc b) abc c) 1 d) 0 Ans. 73. The locus of the point Z satisfying the condition arg −+

= is a) x2-y2-2√3y = 0 b) x2+ y2= 1 c) x2-y2-2√3y-1 = 0 d) x2+ y2-2√3y-1 = 0 Ans. 74. In a simple micrometer with screw pitch 0.5 mm and divisions on

thimble 50, the reading corresponding to 5 divisions on barrel and 12

divisions on thimble is

a) 2.620mm b)2.512 mm c) 5.120 mm d) 5.012mm Ans.

75. It is required to cut screw threads of 2mm pitch on a lathe. The lead

screw has a pitch of 6 mm. If the spindle speed is 60 rpm, then the speed

of the lead screw will be

a) 10 rpm b) 20 rpm c) 120 rpm d) 180 rpm Ans.

76. If u = log (tan x + tan y), then sin 2x +sin 2y is

a)1 b)-2 c)2 d)-1 Ans. 77. The value of λ for which the equations 2λx — 3y + λ — 3 = 0, 3x— 2y

+ 1 = 0 and 4x — λy +2 = 0 are consistent is

a)3or 6 b) 1or3 c) 2 or 6 d) 2 or3 Ans.

78. 1f + + = 0 and ∣ ∣= 3, ∣ ∣= 5, ∣ ∣= 7, then the angle between and

is

a) 450 b)300 c) 900 d) 60° Ans.

79. The image of the point P(1,3,4) in the plane 2x — y + z -3 is

a)(-3,5,-2) b)(-3,-5,2) c)(3,-5,-2) d)(-3,5,2) Ans.

80. Find a particular integral of the differential equation (D2 – 4D + 3)y =

sin3xcos2x a)120(10cos5x–11sin5x) + 1 884(sin x–2cosx) b) 1 884(10cos5x–11sin5x) +120(sin x + 2cosx)

c)120(10cos5x–11sin5x)+ 1 884(sin x + 2cosx) d) 1 884(