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  #2  
9th November 2015, 10:06 AM
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Join Date: Apr 2013
Re: ONGC Recruitment Papers for Mechanical

Here I am providing sample question papers for ONGC Recruitment for B.Tech Mechanical Engineering Degree Holders:

ONGC Mechanical Engineering Paper 1
1 What is the difference between isotropic and anisotropic materials?
Ans If a material exhibits same mechanical properties regardless of loading direction, it is isotropic eg., homogeneous cast materials. Materials lacking this property are anisotropic

2 what are orthotropic materials
It is a special class of anisotropic materials which can be described by giving their properties in three perpendicular direction et wood composites

3 A plain carbon steel has BHN of 180 What are values of Rc, VHN and ultimate strength?
Ans Rc-RHN/10 18,VHN BHN 180

4 What properties need to be considered for applications calling for following requirement:
irigdity

strength for no plastic deformation under static load

wear resistance

reliability and safety

Ans Rigidity- elastic modules and yield strength

Strength for no plastic deformation under static loading-yield point

Wear resistance-Hardness

Reliability and safety-Endurance limit and yield point

5 Explain the effects of alloying chromium and nickel in stainless steel.
Addition of nickel and chromium increases the tensile strength and increase in resistance to corrosion takes place.

6 Mention two types of dislocation,
Dislocation refers to a break in the continuity of the lattice. In edge dislocation, one place of atoms gets squeezed out.In screw dislocation the lattice atoms move from their regular ideal positions.

7 What are the principal constituents of brass?
Principal constituents of brass are copper and zinc

8 what is curie point?
Curie point is te temperature at which ferromagnetic materials can no longer be magnetized by outside forces

9 Specific strength of materials is very high when they are in fiber size but lower when they are in bar form-Why?
Crystal structure has ordered, repeating arrangement of atoms, fibers are liable to maintain this and thus have high specific strength. As size increases, the condition of ordered and repeating arrangements cant be guaranteed because of several types of defects and dislocations and thus the specific strength gets lower

10 what is the percentage of carbon in cast iron?
2.5%

11 Which element is added in steel to increase resistance to corrosion?
Chromium

12 whether individual component material retain their characteristics or not
Yes

13 An elastomer is a polymer when its percentage elongation rate is
Greater than 100%

14 If % elongation of material is more tha 200% it is classed as
Rubber

15 Why is it that the maximum value which the residual stress can reach is the elastic limit of the material?
A stress in excess of elastic limit with no external force to oppose it will relieve itself by plastic deformation until it reaches the value of the yield stress

16 Why fatigue strength decreases as size of a part increase beyond around 10 mm?
Perfection of material conditions is possible at lower sizes and as size increases, it is not possible to attain uniform structure of the material

17 Distinguish between creep and fatigues
Creep is low and progressive deformation of a material with time under a constant stress at high temperature application. Fatigue is the reduced tendency of material to offer resistance to applied stress under repeated or fluctuating loading conditions?

18 While normal carbursing and nitriding surface treatments increase fatigue strength excessive treatment may decrease the fatigue strength Why
Normal carbursing/nitiriding treatments increase volume due to phase transformation at surface and introduce residual compressive surface stress and thus increase the fatigue strength, By excessive treatment the high compressive stresses are introduced but these are balanced by high internal tensile stresses of equal value and the subsurface fatigue cracks may develop in the regions of high tensile stress and lead to early fatigue failures

19 List at least two factors that promote transition form ductile to brittle fracture
Manner of loading and the rate of loading promote transition from ductile to brittle fracture, A machine member may have ductile failure under static loading but may fail in brittle fashion when the load is fluctuating Similarly a material may evidence ductile failure under tensile loading at ordinary testing speed but if load is applied at a high velocity then failure may be brittle

20 Which theories of failure are used for (a) ductile material and (b) brittle materials
For ductile materials theories of failure used are maximum shear stress theory, and maximum energy of distortion theory, while for brittle materials theory of maximum principal stress and maximum strain are used

21 what is stellite?

I t is a non ferrous cast alloy containing cobalt chromium and tungsten

22 Car tyres are usually made of
styrene butadine rubbe

23 What is the structure of pure iron and whether it is soft or hard?
Ferrite and it is soft

24 which elements increase the corrosion resistance of steel?
Chromium and nickel

25 Which rays are produced by cobalt 60 in industrial radiography?
Gamma rays

ONGC Mechanical Engineering Paper 2
1. Pascal-second is the unit of
a) pressure
b) kinematic viscosity
c) dynamic viscosity
d) surface tension
Ans: c

2. An ideal fluid is
a) one which obeys Newton,s law of viscosity
b) frictionless and incompressible
c) very viscous
d) frictionless and compressible
Ans: b

3. The unit of kinematic viscosity is
a) gm/cm-sec2
b) dyne-sec/cm2
c) gm/cm2-sec
d) cm2/sec
Ans: d

4. If the dynamic viscosity of a fluid is 0.5 poise and specific gravity is 0.5, then the kinematic viscosity of that fluid in stokes is
a) 0.25
b) 0.50
c) 1.0
d) none of the above
Ans: c

5. The viscosity of a gas
a) decreases with increase in temperature
b) increases with increase in temperature
c) is independent of temperature
d) is independent of pressure for very high pressure intensities
Ans: b

6. Newton,s law of viscosity relates
a) intensity of pressure and rate of angular deformation
b) shear stress and rate of angular deformation
c) shear stress, viscosity and temperature
d) viscosity and rate of angular deformation
Ans: b

7. An open tank contains 1 m deep water with 50 cm depth of oil of specific gravity 0.8 above it. The intensity of pressure at the bottom of tank will be
a) 4 kN/m2
b) 10 kN/m2
c) 12 kN/m2
d) 14 kN/m2
Ans: d

8. The position of center of pressure on a plane surface immersed vertically in a static mass of fluid is
a) at the centroid of the submerged area
b) always above the centroid of the area
c) always below the centroid of the area
d) none of the above
Ans: c

9. The total pressure on a plane surface inclined at an angle 9 with the horizontal is equal to
a) PA
b) pA sin 9
c) pA cos 9
d) pA tan 9
where p is pressure intensity at centroid of area and A is area of plane surface.
Ans: a

10. A vertical rectangular plane surface is submerged in water such that its top and bottom surfaces are 1.5 m and 6.0 m res-pectively below the free surface. The position of center of pressure below the free surface will be at a distance of
a) 3.75 m
b) 4.0 m
c) 4.2m
d) 4.5m
Ans: c

11. Centre of buoyancy always
a) coincides with the centre of gravity
b) coincides with the centroid of the volume of fluid displaced
c) remains above the centre of gravity
d) remains below the centre of gravity
Ans: b

12. If the weight of a body immersed in a fluid exceeds the buoyant force, then the body will
a) rise until its weight equals the buoyant force
b) tend to move downward and it may finally sink
c) float
d) none of the above
Ans: b

13. Metacentric height for small values of angle of heel is the distance between the
a) centre of gravity and centre of buoy-ancy
b) centre of gravity and metacentre
c) centre of buoyancy and metacentre
d) free surface and centre of buoyancy
Ans: b

14. A floating body is said to be in a state of stable equilibrium
a) when its metacentric height is zero
b) when the metacentre is above the centre of gravity
c) when the metacentre is below the centre of gravity
d) only when its centre of gravity is below its centre of buoyancy
Ans: b

15. The increase in meta centric height
i) increases stability
ii) decreases stability
iii) increases comfort for passengers
iv) decreases comfort for passengers
The correct answer is
a) (i) and (iii)
b) (i)and(iv)
c) (ii) and (iii)
d) (ii) and (iv)
Ans: b

16. A rectangular block 2 m long, 1 m wide and 1 m deep floats in water, the depth of immersion being 0.5 m. If water weighs 10 kN/m3, then the weight of the block is
a) 5kN
b) lOkN
c) 15 kN
d) 20 kN
Ans: b

17. The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as
a) center of gravity
b) center of buoyancy
c) center of pressure
d) metacentre
Ans: c

18. If a vessel containing liquid moves downward with a constant acceleration equal to ,g, then
a) the pressure throughout the liquid mass is atmospheric
b) there will be vacuum in the liquid
c) the pressure in the liquid mass is greater than hydrostatic pressure
d) none of the above
Ans: a

19. When a liquid rotates at a constant angular velocity about a vertical axis as a rigid body, the pressure intensity varies
a) linearly with radial distance
b) as the square of the radial distance
c) inversely as the square of the radial distance
d) inversely as the radial distance
Ans: b

20. An open cubical tank of 2 m side is filled with water. If the tank is rotated with an acceleration such that half of the water spills out, then the acceleration is equal to
a) g/3
b) g/2
c) 2g/3
d) g
Ans: d
  #3  
21st February 2020, 11:48 AM
Unregistered
Guest
 
Re: ONGC Recruitment Papers for Mechanical

I have completed B.Tech Degree with Mechanical Engineering Discipline. Now I want to start preparation for ONGC Recruitment Exam. So will you pls provide sample question papers for Mechanical Branch for ONGC Recruitment?


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