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HAL Placement Paper : HAL Placement Paper Aeronautical-Avionics-Aerospace 07 November 2012

HAL Aeronautical / Avionics / Aerospace Engineering questions
1. Air Fuel ratio in a jet engine will be of the order of:
(a) 10:1
(b) 15:1
(c) 20:1
(d) 60:1

2. Fighter bombers use following type of engine:
(a) Turbo-jet
(b) Turbo-propeller
(c) Rocket
(d) Ram-jet

3. Least shrinkage allowance is provided in the case of following:
(a) Brass
(b) Aluminium
(c) Cast Iron
(d) Steel

4. If V is the volume of metal in a casting and A its surface area, the time of solidification will be proportional to:
(a) V, 1/A
(b) V,1/A2
(c ) V2 ,1/A
(d) V2, 1/A2

5. Fire tube boilers are limited to a maximum design working pressure of :
(a) 1 kg/cm2
(b) 6 kg/cm2
(C) 17 kg/cm2
(d) 100 kg/cm2

What are the characteristics that keep solid and fluid different?

• When the force is applied tangentially on solid then it experiences a finite deformation and shear stress that is proportional to the deformation. Whereas, when the same shear stress is applied on the surface of fluid then it

experiences continuous increasing deformation where, the shear stress is proportional to the rate of change of deformation.
• The fluid dynamic is dividend in three different areas. They are as follows: Hydrodynamics (flow of liquids), Gas dynamics (flow of gases) and Aerodynamics (flow of air). Whereas, the state of, solid doesn’t represent any of

the stages.
What are the objectives of Aerodynamics?

Aerodynamics deals with the theory of flow of air and it has many practical applications in engineering. There are some objectives that are being used in aerodynamics and these are as follows:
• It is used to predict the forces, moments and heat transfer from the bodies that is moving through the liquid.
• It deals with the movement of wings or use of the wind force. This way it requires the calculations to be done for the aerodynamic heating of the flight vehicles and the hydrodynamic forces applied on the surface of the

• It is used to determine the flows that are moving internally through ducts. This way it makes the calculations and measurement of the flow properties that is inside the rocket and jet engines.
What are the sources involved in aerodynamics?

There are two sources that are involved in the case of aerodynamics forces and moments that are on the body. These forces are as follows:
• Pressure distribution: this is the distribution that is over the body surface
• Shear stress distribution: this is the distribution that is over the body surface
These sources are for the body shapes and it doesn’t matter how complex they are. The mechanism that is being used to communicate with the bodies that is moving through a fluid. Both the pressure (p) and shear stress (?)

having the dimension force per unit area. This helps the movement of the body through the fluid.
What are the conditions given for the two flows to be dynamically similar?

To measure the dynamicity of the two flows consider two different flow fields over two different bodies. This way the conditions that get generated are as follows:
• The streamlined pattern shouldn’t be geometrically similar.
• The distribution of the volume over change in volume (V/V8), pressure over change in pressure (p/p8), and time over change in time (T/T8). These changes take place throughout the flow of the field and they remain the

same against the common non-dimensional coordinates
• The force coefficient remains the same.
• There is a similarity in both the flows like the solid boundaries are geometrically similar for both flows.
What are the differences between continuum flow and free molecule flow?

• The flow that is moving over the body i.e. in a circular cylinder of diameter d is the continuum flow, whereas the flow that consists of individual molecules moving in random motion is the free molecule flow.
• The mean free path (?) defines the mean distance between the collisions of the molecule and if this path (?) is smaller than the scale of the body measured (d) then the flow of the body is considered as continuum flow.
• The path (?) that is of same order as the body scale then the gas molecules then the body surface will have an impact of the molecules and this is known as free molecular flow.
What are the differences between inviscid and viscous flow?

• Viscous flow is the flow in which the molecule moves in random fashion and transfers their mass, momentum and energy from one place to another in fluid. Whereas, an inviscid flow is the flow in which there is no

involvement of friction, thermal conduction or diffusion while the molecules are moving.
• Inviscid flow consists of the limited influence of friction, thermal conduction and diffusion that is limited to thin region that is limited to the body surface. Whereas, the viscous flows involve the flows that dominates the

aerodynamics of the blunt bodies like cylinder. In this the flow expands around front face of cylinder and it separates from the rear surface of it.

HAL Placement Paper : HAL Placement Paper Mechanical engineering 04 November 2012

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:


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?


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


12 whether individual component material retain their characteristics or not


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


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

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

21. A right circular cylinder open at the top is filled with liquid and rotated about its vertical axis at such a speed that half the liquid spills out, then the pressure intensity at the center of bottom is
a) zero
b) one-fourth its value when cylinder was full
c) one-half its value when cylinder was full
d) cannot be predicted from the given data
Ans: a

22. The horizontal component of force on a curved surface is equal to the
a) product of pressure intensity at its centroid and area
b) force on a vertical projection of the curved surface
c) weight of liquid vertically above the curved surface
d) force on the horizontal projection of the curved surface
Ans: b

23. A closed tank containing water is moving in a horizontal direction along a straight line at a constant speed. The tank also contains a steel ball and a bubble of air. If the tank is decelerated horizontally, then
i) the ball will move to the front
ii) the bubble will move to the front
iii) the ball will move to the rear
iv) the bubble will move to the rear Find out which of the above statements are correct ?
a) (i) and (ii)
b) (i)and(iv)
c) (ii) and (iii)
d) (iii) and (iv)
Ans: b

24. The eddy viscosity for turbulent flow is
a) a function of temperature only
b) a physical property of the fluid.
c) dependent on the flow
d) independent of the flow
Ans: c

25. Flow at constant rate through a tapering pipe is
i) steady flow
ii) uniform flow
iii) unsteady flow
iv) non-uniform flow
The correct answer is
a) (i) and (ii)
b) (i)and(iv)
c) (ii) and (iii)
d) (ii) and (iv)
Ans: b

26. In a two dimensional incompressible steady flow around an airfoil, the stream lines are 2 cm apart at a great distance from the airfoil, where the velocity is 30 m/sec. The velocity near the airfoil, where the stream lines are 1.5 cm apart, is
a) 22.5 m/sec.
b) 33 m/sec.
c) 40 m/sec.
d) 90 m/sec.
Ans: c

27. When the velocity distribution is uniform over the cross-section, the correction factor for momentum is
a) 0
b) 1
c) 4/3
d) 2
Ans: b

28. Least possible value of correction factor for
i) kinetic energy is zero
ii) kinetic energy is 1
iii) momentum is zero
iv) momentum is 1
The correct statements are
a) (i) and (iii)
b) (ii) and (iii)
c) (i) and (iv)
d) (ii) and (iv)
Ans: d

29. If the velocity is zero over half of the cross-sectional area and is uniform over the remaining half, then the momentum correction factor is
a) 1
b) 4/3
c) 2
d) 4
Ans: c

30. If velocity is zero over l/3rd of a cross-section and is uniform over remaining 2/3rd of the cross-section, then the correction factor for kinetic energy is
a) 4/3
b) 3/2
c) 9/4
d) 27/8
Ans: c

31. The continuity equation
pi V,A,= p2V2A2 is based on the following assumption regarding flow of fluid
a) steady flow
b) uniform flow
c) incompressible flow
d) frictionless flow
where pi and p2 are mass densities.
Ans: a

32. Which of the following velocity potentials satisfies continuity equation ?
a) x2y
b) x2-y2
c) cosx
d) x2 + y2
Ans: b

33. The motion of air mass in a tornado is a
a) free vortex motion
b) forced vortex motion
c) free vortex at center and forced vortex outside
d) forced vortex at center and free vortex outside
Ans: d

34. In a forced vortex motion, the velocity of flow is
a) directly proportional to its radial distance from axis of rotation
b) inversely proportional to its radial distance from the axis of rotation
c) inversely proportional to the square of its radial distance from the axis of rotation
d) directly proportional to the square of its radial distance from the axis of rotation
Ans: a

35. Stream lines and path lines always coincide in case of
a) steady flow
b) laminar flow
c) uniform flow
d) turbulent flow
Ans: a

36. Equation of continuity is based on the principle of conservation of
a) mass
b) energy
c) momentum
d) none of the above
Ans: a

37. In steady flow of a fluid, the total accele ration of any fluid particle
a) can be zero
b) is never zero
c) is always zero
d) is independent of coordinates
Ans: a

38. The pitot tube is used to measure
a) velocity at stagnation point
b) stagnation pressure
c) static pressure
d) dynamic pressure
Ans: b

39. Hot wire anemometer is used to measure
a) discharge
b) velocity of gas
c) pressure intensity of gas
d) pressure intensity of liquid
Ans: b

40. The theoretical value of coefficient of contraction of a sharp edged orifice is
a) 0.611
b) 0.85
c) 0.98
d) 1.00
Ans: a

41. Which of the following is used to measure the discharge ?
a) current meter
b) venturimeter
c) pitot tube
d) hotwire anemometer
Ans: b

42. Select the incorrect statement.
a) The pressure intensity at vena contracta is atmospheric.
b) Contraction is least at vena contracta.
c) Stream lines are parallel throughout the jet at vena contracta.
d) Coefficient of contraction is always less than one.
Ans: c

43. Size of a venturimeter is specified by
a) pipe diameter
b) throat diameter
c) angle of diverging section
d) both pipe diameter as well as throat diameter
Ans: a

44. Due to each end contraction, the discharge of rectangular sharp crested weir is reduced by
a) 5%
b) 10%
c) 15%
d) 20%
Ans: a

45. The discharge through a V- notch varies as
a) H1/2
b) H3,2
c) H5/2
d) H5,4 where H is head.
Ans: c

46. Which of the following is an incorrect statement ?
a) Coefficient of contraction of a venturimeter is unity.
b) Flow nozzle is cheaper than venturimeter but has higher energy loss.
c) Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined.
d) None of the above statement is correct.
Ans: d

47. Coefficient of velocity of venturimeter
a) is independent of Reynolds number
b) decreases with higher Reynolds number
c) is equal to the coefficient of discharge of venturimeter
d) none of the above
Ans: c

48. The pressure at the summit of a syphon is
a) equal to atmospheric
b) less than atmospheric
c) more than atmospheric
d) none of the above
Ans: b

49. Ay between two stream lines represents
a) velocity
b) discharge
c) head
d) pressure
Ans: b

50. Coefficient of velocity for Borda,s mouth piece running full is
a) 0.611
b) 0.707
c) 0.855
d) 1.00
Ans: b

51. Coefficient of discharge for a totally submerged orifice as compared to that for an orifice discharging free is
a) slightly less
b) slightly more
c) nearly half
d) equal
Ans: a

52. The major loss of energy in long pipes is due to
a) sudden enlargement
b) sudden contraction
c) gradual contraction or enlargement
d) friction
Ans: d

53. Coefficient of contraction for an external cylindrical mouthpiece is
a) 1.00
b) 0.855
c) 0.7H
d) 0.611
Ans: a

54. Which of the following has highest coefficient of discharge ?
a) sharp edged orifice
b) venturimeter
c) Borda,s mouthpiece running full
d) CipoUetti weir
Ans: b

55. In a Sutro weir, the discharge is proportional to
a) H1/2
b) H3/2
c) H5/2
d) H
where H is head.
Ans: d

56. The discharge over a broad crested weir is maximum when the depth of flow is
a) H/3
b) H/2
c) 2 H/5
d) 2 H/3
where H is the available head.
Ans: d

57. Which of the following statements is correct?
a) Lower critical Reynolds number is of no practical significance in pipe flow problems.
b) Upper critical Reynolds number is significant in pipe flow problems.
c) Lower critical Reynolds number has the value 2000 in pipe flow
d) Upper critical Reynolds number is the number at which turbulent flow changes to laminar flow.
Ans: a

58. For a sphere of radius 15 cm moving with a uniform velocity of 2 m/sec through a liquid of specific gravity 0.9 and dynamic viscosity 0.8 poise, the Reynolds number will be
a) 300
b) 337.5
c) 600
d) 675
Ans: d

59. The shear stress distribution for a fluid flowing in between the parallel plates, both at rest, is
a) constant over the cross section
b) parabolic distribution across the section
c) zero at the mid plane and varies linearly with distance from mid plane
d) zero at plates and increases linearly to midpoint
Ans: c

60. If x is the distance from leading edge, then the boundary layer thickness in laminar flow varies as
a) x
b) x
c) x
d) x/7
Ans: a

61. Stanton diagram is a
a) log-log plot of friction factor against Reynolds number
b) log-log plot of relative roughness against Reynolds number
c) semi-log plot of friction factor against Reynolds number
d) semi-log plot of friction factor against relative roughness
Ans: a

62. The depth ,d, below the free surface at which the point velocity is equal to the average velocity of flow for a uniform laminar flow with a free surface, will be
a) 0.423 D
b) 0.577 D
c) 0.223 D
d) 0.707 D
where D is the depth of flow.
Ans: b

63. The boundary layer thickness in turbulent flow varies as
a) x"7
b) x,/2
c) x4/5
d) x3/5
where x is the distance from leading edge.
Ans: c

64. The distance y from pipe boundary, at which the point velocity is equal to average velocity for turbulent flow, is
a) 0.223 R
b) 0.423 R
c) 0.577 R
d) 0.707 R
where R is radius of pipe.
Ans: a

65. If a sphere of diameter 1 cm falls in castor oil of kinematic viscosity 10 stokes, with a terminal velocity of 1.5 cm/sec, the coefficient of drag on the sphere is
a) less than 1
b) between 1 and 100
c) 160
d) 200
Ans: c

66. In case of an airfoil, the separation of flow occurs
a) at the extreme rear of body
b) at the extreme front of body
c) midway between rear and front of body
d) any where between rear and front of body depending upon Reynolds number
Ans: a

67. When an ideal fluid flows past a sphere,
a) highest intensity of pressure occurs around the circumference at right angles to flow
b) lowest pressure intensity occurs at front stagnation point
c) lowest pressure intensity occurs at rear stagnation point
d) total drag is zero
Ans: d

68. With the same cross-sectional area and immersed in same turbulent flow, the largest total drag will be on
a) a circular disc of plate held normal to flow
b) a sphere
c) a cylinder
d) a streamlined body
Ans: a

69. In which of the following the friction drag is generally larger than pressure drag?
a) a circular disc or plate held normal to flow
b) a sphere
c) a cylinder
d) an airfoil
Ans: d

70. For hydro-dynamically smooth boundary, the friction coefficient for turbulent flow is
a) constant
b) dependent only on Reynolds number
c) a function of Reynolds number and relative roughness
d) dependent on relative roughness only
Ans: b

71. The value of friction factor ,f, for smooth pipes for Reynolds number 106 is approximately equal to
a) 0.1
b) 0.01
c) 0.001
d) 0.0001
Ans: b

72. For laminar flow in a pipe of circular cross-section, the Darcy,s friction factor f is
a) directly proportional to Reynolds number and independent of pipe wall roughness
b) directly proportional to pipe wall roughness and independent of Reynolds number
c) inversely proportional to Reynolds number and indpendent of pipe wall roughness
d) inversely proportional to Reynolds number and directly proportional to pipe wall roughness
Ans: c

73. Separation of flow occurs when
a) the pressure intensity reaches a minimum
b) the cross-section of a channel is reduced
c) the boundary layer comes to rest
d) all of the above
Ans: c

74. The ratio of average velocity to maximum velocity for steady laminar flow in circular pipes is
a) 1/2
b) 2/3
c) 3/2
d) 2
Ans: a

75. The distance from pipe boundary, at which the turbulent shear stress is one-third die wall shear stress, is
a) 1/3 R
b) 1/2 R
c) 2/3 R
d) 3/4R
where R is the radius of pipe.
Ans: a

76. The discharge of a liquid of kinematic viscosity 4 cm2/sec through a 8 cm dia-meter pipe is 3200n cm7sec. The type of flow expected is
a) laminar flow
b) transition flow
c) turbulent flow
d) not predictable from the given data
Ans: a

77. The Prartdtl mixing length is
a) zero at the pipe wall
b) maximum at the pipe wall
c) independent of shear stress
d) none of the above
Ans: a

78. The velocity distribution for laminar flow through a circular tube
a) is constant over the cross-section
b) varies linearly from zero at walls to maximum at centre
c) varies parabolically with maximum at the centre
d) none of the above
Ans: c

79. A fluid of kinematic viscosity 0.4 cm2/sec flows through a 8 cm diameter pipe. The maximum velocity for laminar flow will be
a) less than 1 m/sec
b) 1 m/sec
c) 1.5 m/sec
d) 2 m/sec
Ans: b

80. The losses are more in
a) laminar flow
b) transition flow
c) turbulent flow
d) critical flow
Ans: c

81. The wake
a) always occurs before a separation point
b) always occurs after a separation point
c) is a region of high pressure intensity
d) none of the above
Ans: b

82. The maximum thickness of boundary layer in a pipe of radius r is
a) 0
b) r/2
c) r
d) 2r
Ans: c

83. The hydraulic grade line is
a) always above the centre line of pipe
b) never above the energy grade line
c) always sloping downward in the direction of flow
d) all of the above
Ans: b

84. Two pipe systems are said to be equivalent when
a) head loss and discharge are same in two systems
b) length of pipe and discharge are same in two systems
c) friction factor and length are same in two systems
d) length and diameter are same in two systems
Ans: a

85. In series-pipe problems
a) the head loss is same through each pipe
b) the discharge is same through each pipe
c) a trial solution is not necessary
d) the discharge through each pipe is added to obtain total discharge
Ans: b

86. Select the correct statement.
a) The absolute roughness of a pipe de-creases with time.
b) A pipe becomes smooth after using for long time.
c) The friction factor decreases with time.
d) The absolute roughness increases with time.
Ans: d

87. A valve is suddenly closed in a water main in wl.ich the velocity is 1 m/sec and velocity of pressure wave is 981 m/ sec. The inertia head at the valve will be
a) 1 m
b) 10m
c) 100m
d) none of the above
Ans: c

88. The speed of a pressure wave through a pipe depends upon
a) the length of pipe
b) the viscosity of fluid
c) the bulk modulus for the fluid
d) the original head
Ans: c

89. When time of closure tc = L/v0 (where L is length of pipe and v0 is speed of pressure wave), the portion of pipe length subjected to maximum head is
a) L/4
b) L/3
c) L/2
d) L
Ans: a

90. If the elevation of hydraulic grade line at the junction of three pipes is above the elevation of reservoirs B and C and below reservoir A, then the direction of flow will be
a) from reservoir A to reservoirs B and C
b) from reservoir B to reservoirs C and A
c) from reservoir C to reservoirs A and B
d) unpredictable
Ans: c

91. The length of a pipe is 1 km and its diameter is 20 cm. If the diameter of an equivalent pipe is 40 cm, then its length is
a) 32 km
b) 20 km
c) 8 km
d) 4 km
Ans: a

92. Two pipes of same length and diameters d and 2d respectively are connected in series. The diameter of an equivalent pipe of same length is
a) less than d
b) between d and 1.5 d
c) between 1.5 d and 2d
d) greater than 2d
Ans: a

93. The horse power transmitted through a pipe is maximum when the ratio of loss of head due to friction and total head supplied is
a) 1/3
b) 1/4
c) 1/2
d) 2/3
Ans: a

94. The boundary layer thickness at a distance of l m from the leading edge of a flat plate, kept at zero angle of incidence to the flow direction, is O.l cm. The velocity outside the boundary layer is 25 ml sec.
The boundary layer thickness at a distance of 4 m is
a) 0.40 cm
b) 0.20 cm
c) 0.10 cm
d) 0.05 cm
Assume that boundary layer is entirely laminar.
Ans: b

95. Drag force is a function of
i) projected area of the body
ii) mass density of the fluid
iii) velocity of the body
The correct answer is
a) (i) and (ii)
b) (i) and (iii)
c) (ii) and (iii)
d) (i), (ii) and (iii)
Ans: d

96. The correct relationship among displacement thickness d, momentum thickness m and energy thickness e is
a) d > m > e
b) d > e > m
c) e > m > d
d) e > d > m
Ans: d

97. For laminar flow in circular pipes, the Darcy,s friction factor f is equal to
a) 16/Re
b) 32/ Re
c) 64/ Re
d) none of the above where R,, is Reynolds number.
Ans: c

98. Surge wave in a rectangular channel is an example of
i) steady flow
ii) unsteady flow
iii) uniform flow
iv) non-uniform flow
The correct answer is
a) (i) and (iii)
b) (ii) and (iii)
c) (i) and (:v)
d) (ii) and (iv)
Ans: d

HAL Placement Paper : HAL Placement Paper Computer questions 04 November 2012

HAL Multiple Choice Questions

1. A computer derives its basic strength from

(a) speed

(b) accuracy

(c) memory

(d) all of the above (Ans)

(e) None of the above.

2. Modern computers compared to earlier computers are

(a) faster and larger

(b) less reliable

(c) larger and stronger

(d) slower but more reliable

(e) faster and smaller (Ans)

3. The use of computer for business applications is attractive because of its

(a) accuracy

(b) reliability

(c) speed

(d) secret code facility

(e) All of the above (Ans)

4. A computer is capable of performing almost any task, provided that it can be

(a) coded

(b) memorized

(c) analyzed

(d) reduced to a series of logical steps (Ans)

(e) changed top mathematics equation

5. A BIT represents a

(a) decimal digit

(b) octal digit

(c) binary digit (Ans)

(d) hexa decimal digit

6. A computer has very high speed, accuracy and reliability. Its intelligence quotient could be of the order of

(a) 100

(b) 0 (Ans)

(c) 50

(d) 200

(e) 99.99

7. Computer can not do anything without a

(a) chip

(b) memory

(c) output device

(d) program (Ans)

(e) None of the above

8. A computer possesses information

(a) as directed by the operator

(b) automatically (Ans)

(c) at once

(d) gradually and eventually

(e) by truncating

9. Pick up the false statement

(a) computer can manipulate both numeric and non-numeric symbols

(b) computer errors can usually be traced to faulty programs or inaccurate input data

(c) the facts or informational raw materials represented by numeric and non-numeric symbols are called information (Ans)

(d) the space in the primary storage section is divided into four areas: input, working, storage, output and program storage.

(e) Information is the relevant knowledge that results from the processing and arranging of data in an ordered and useful form.

10. Processors of all computers, whether micro, mini or mainframe must have

(a) ALU

(b) primary storage

(c) control Unit

(d) all of the above (Ans)

(e) None of the above.

11. Pick up the correct statement about computers

(a) computers process data with human intervention after the program has been fed

(b) all comparisons are made in the control section

(c) the arithmetic-logic section of the CPU selects, interprets and executes the program steps.

(d) the secondary storage devices are usually connected on line to the CPU but for accepting data from them or returning data to them, human intervention is required

(e) computers have the built-in ability to obey different types of instructions. (Ans)

12. Real time computing is possible because of the following characteristic of computer

(a) storage capability

(b) high speed (Ans)

(c) accuracy

(d) versatility

(e) automatic in execution

13. Pick out the wrong statement about modern computer systems

(a) these are simple and easy to take care of

(b) even beginners, untrained persons can safely handle them (Ans)

(c) they require a highly disciplined approach

(d) it is important to understand the proper overall procedures must be followed

(e) the negligent use of a computer system will almost always introduce time bombs into the system.

14. A collection of eight bits is called:

(a) byte (Ans)

(b) word

(c) record

(d) file

(e) None of the above

15. Choose the incorrect statement about micro computers, mini-computers, etc.

(a) a microcomputer can be placed on a single silicon chip

(b) a minicomputer can have more processing capability than a mainframe model

(c) a microcomputer chip performs the arithmetic-logic and control functions of a microcomputer

(d) ROM chips may be used in micros ;to permanently store program instruction

(e) most micros use rigid disk storage devices rather than floppy disk drives. (Ans)

16. Control Unit of a digital computer is often called the

(a) lock

(b) nerve center (Ans)

(c) ICs

(d) all of the above

(e) None of the above

17. Pick up the correct statement

(a) most mainframes are 48-bit machines

(b) thousands of super computers are currently being built

(c) super-computers are usually designed to process accounting applications

(d) mainframes may have multi-processor components that permit several tasks to be processed at the same instant in time (Ans)

(e) minicomputers can not use high speed buffer storage components and are thus always slower than mainframe models.

18. The following acronym recognizes the fact that "computer errors" can usually be traced to incorrect input data or unreliable programs

(a) IGO (Ans)

(b) FIFO

(c) LIFO

(d) DASD

(e) ROM

19. Group of instructions that directs a computer is called

(a) storage

(b) memory (Ans)

(c) logic

(d) program

(e) None of the above

20. Which of the following does not describe one or more characteristics of a computer?

(a) electronic

(b) external storage

(c) stored program

(d) program modification at execution (Ans)

(e) All of the above are characteristics.

21. Which of the following statements is true?

(a) the smart approach to using computers is to write programs

(b) knowledge of the system development life cycle is not important to operators who use computers without programming

(c) hands-on exposure to the computer is not helpful to those who write programs

(d) personal computer have been an important contributing factor in the movement towards using computers without programming (Ans)

(e) None of the above is true

22. Which can read data and convert them to a form that a computer can use?

(a) logic

(b) storage

(c) control

(d) input device (Ans)

(e) output device

23. Software instruction intended to satisfy a user,s specific processing needs are called

(a) system software

(b) a microcomputer

(c) documentation

(d) applications software (Ans)

(e) All of the above

24. Which kind of hardware is used the most in the input phase of a computer based information system?

(a) keyboard (Ans)

(b) printer

(c) monitor

(d) hard disk

(e) floppy disk

25. Which of the following is not a factor when categorizing a computer

(a) amount of main memory the CPU can use

(b) capacity of the storage devices

(c) cost of the system

(d) where it was purchased (Ans)

(e) speed of the output device

26. Which of the following is the most powerful type of computer?

(a) super micro

(b) super conductor

(c) microcomputer

(d) super computer (Ans)

(e) megaframe

27. Which of the following people probably has the least amount of technical knowledge ?

(a) programmer

(b) user (Ans)

(c) system analyst

(d) computer operator

(e) computer professional

28. Which kind of storage device cab be carried around?

(a) floppy disk (Ans)

(b) hard disk

(c) system cabinet

(d) hard disk drive

(e) floppy disk drive

29. Which of the following terms applies to communication between separate computer systems?

(a) computer literacy

(b) power supply

(c) applications software

(d) connectivity (Ans)

(e) None of the above

30. The Central Processing Unit (CPU) consists of:

(a) input, output and processing

(b) control unit, primary storage & secondary storage

(c) control unit, arithmetic-logic unit, primary storage (Ans)

(d) control unit, processing, primary storage

(e) None of the above

31. People typically interface with a computer based system when:

(a) information must be output

(b) data must be input

(c) information must be reviewed the computer needs a direction (or instruction) in order to process data

(d) All of the above

(Ans : e)

32. The principle advantage of the centralized approach to organizing a computer facility is :

(a) cost-effectiveness

(b) processing activities are easier to coordinate

(c) Processing activities are easier to control

(d) processing statements can be enforced

(e) All of the above (Ans)

33. The fifth generation digital computer will be

(a) extremely low cost

(b) very expensive

(c) versatility

(d) artificial intelligence (Ans)

(e) None of the above

34. To be information, data must be

(a) factual

(b) relevant

(c) news

(d) all of the above (Ans)

(e) None of the above

35. A data system for calculating measures used in statistical inference is an example of a

(a) teleprocessing system

(b) data management system

(c) computing system (Ans)

(d) All of the above

(e) None of the above

36. For the purposes of defining data needs, a responsibility area is

(a) marketing

(b) administration

(c) personal (Ans)

(d) all of the above

(e) None of the above

37. Which is widely used in academic testing?

(a) MICR

(b) POS

(c) OCR

(d) OMR (Ans)

(e) None of the above

38. Coded entries which are used to gain access to a computer system are called:

(a) entry codes

(b) passwords (Ans)

(c) security commands

(d) code words

39. A factor which might cause an individual to consider using a computer in criminal activities is :

(a) the computer,s access to large sums to money

(b) the speed with which the crime can be accomplished

(c) EFTS (Electronic Funds Transfer System)

(d) All of the above (Ans)

40. EBCDIC can code up to how may different characters ?

(a) 816

(b) 32

(c) 64

(d) 256

(Ans : e)

41. Which of the following statements is true?

(a) the installation of a computer is favorably received by all employees

(b) some form of training is necessary for employees who will work with computers (Ans)

(c) computers are portrayed solely as society,s benefactor

(d) a business person is only interested in the computer,s accuracy.

42. Which is considered a direct entry input device?

(a) optical scanner

(b) mouse

(c) light pen

(d) digitizer

(e) All of the above (Ans)

43. The daily processing of corrections to customer accounts best exemplifies the processing mode of :

(a) batch processing (Ans)

(b) real-time processing

(c) interactive processing

(d) All of the above

44. The data processing job expected to further decreases in the 1990s is that of :

(a) keypuncher (Ans)

(b) data entry clerk

(c) computer operator

(d) programmer

45. Which is a unit of measurement used with computer systems?

(a) byte

(b) kilobyte

(c) megabyte

(d) gigabyte

(e) All of the above (Ans)

46. Which of the following statements is true?

(a) analysts usually work alone and sometimes as part of a team

(b) most systems projects are completed in 6 12 weeks

(c) an analyst,s primary concern is the development of software

(d) analysts evaluate data flow through an organization (Ans)

47. In computer terminology, information means

(a) raw data

(b) data in more useful or intelligible form (Ans)

(c) alphanumeric data

(d) program

48. A computer programmer

(a) does all the thinking for a computer (Ans)

(b) can enter input data quickly

(c) can operate all types of computer equipment

(d) can draw only flowchart

49. A character is represented in EBCDIC by:

(a) one bit

(b) four bits

(c) eight bits (Ans)

(d) sixteen bits

(e) None of the above

50. Most of the errors blamed on computers are actually due to

(a) programming errors

(b) hardware fatique

(c) defects in floppy disks

(d) data entry errors (Ans)

51. Which is a secondary memory device ?

(a) CPU

(b) ALU

(c) Floppy disk (Ans)

(d) Mouse

(e) None of the above

52. Which is the most significant difference between a simple desk calculator and computer? Choose from the following (note that some of the following may not even be true).

(a) the computer is an electronic machine while the desk calculator may or may not be electronic

(b) the computer is useful in business applications while the desk calculator is not

(c) the computer can print its results, while the desk calculator can only show it on a display

(d) the computer is controlled by a program stored in its memory while calculator require step-by-step manual control (Ans)

(e) One has to know the method of calculation while using a calculator but a computer user can depend upon the computer to choose the method automatically.

53. A term associated with the comparison of processing speeds of different computer systems is :

(a) EFTS

(b) MPG

(c) MIPS (Ans)

(d) CPS

54. RAM is used as a short memory beacuse it

(a) is volatile (Ans)

(b) is very expensive

(c) has small capacity

(d) is programmable

(e) None of the above

55. General purpose computes are those that can be adopted to countless uses simply by changing its.

(a) keyboard

(b) printer

(c) program (Ans)

(d) display screen

(e) None of the above

56. Which is the computer memory that does not forget?

(a) ROM (Ans)

(b) RAM

(c) PROM

(d) All of the above

(e) None of the above

57. The Senta Clara Valley near Palo Alto, California is popularly known as Silicon Valley of America because

(a) huge deposits of silicon are found there

(b) many silicon chip manufacturing firms are located there (Ans)

(c) Santa Claus visits it every Christmas

(d) it is full of large grain sand

58. Computers are incapable of emotional feelings. However, some people attribute humanlike emotions to imitate objects including computers. What is it called?

(a) anthropogenesis

(b) anthropomorphism (Ans)

(c) anthroolatory

(d) cybernetics

59. According to you, which of the following statements is incorrect?

(a) generally, computers don,t make mistakes

(b) computers eliminate jobs

(c) computers can think (Ans)

(d) maths is necessary to understand computers

60. The most common binary code in use today is the 8 bit ASCII code. What do the letters ASCII stand for?

(a) American Standard Code for International Interchange

(b) American Standard Code for Information Interchange (Ans)

(c) American Standard Code for Intelligence interchange

(d) American Scientific Code for Information Interchange

(e) None of the above

HAL Placement Paper : HAL Placement Paper Electronics and Electrical 07 October 2012

HAL Management Trainee Written test Pattern
Written test mode : On line Test
Written Test Type-Objective
Time limit : 2 1/2 Hours
No of Questions :160
Total Parts-3
No of Questions-20 (General Awareness)
Part -2-
No of questions-40 (English and Reasoning)

No of Questions :100 (Concerned Discipline)

HAL electronics and electrical questions with answers

1. When length of a wire increases its resistance

a. doubles b. half c. remains same

Ans: ( a )

2. When a 50 Hz ,6-pole Induction Motor runs at 975rpm,the rotor emf frequency is

a. 12.5Hz b. 1.25Hz c. 4Hz

Ans: ( b )

3. When a 6 pole 50Hz Induction Motor runs at 1450 rpm , it’s working mode is

a. motoring b. braking c. generating

Ans: ( a )

4. Slips for Different modes of operation of Induction Motor are

answer: motoring -01

5. Damping ratio ( ξ ) is 0.75, natural frequency is 12 rad/s are given & asked to find peak time

6. In electrodynamo-meter type wattmeter

a. pressure coil is made fixed

b. current coil is made fixed

c. both the coils are made fixed

Ans: ( a )

7. In flux meter control torque is produced by

a. weights attached to it.

b. Springs

c. No control torque is there

Ans: ( c )

8. One question regarding hot wire instrument

9. In MI meters deflecting torque is proportional to

a. square of the current

b. square of the voltage

Ans: ( a )

10. In 3-Φ system total power is given by

a. √3V­LILcos Φ

b. 3V­LILcos Φ

c. V­LILcos Φ

Ans: ( a )

11. From supply one 3-Φ step-down transformer is drawing 10 A, the secondary current will be minimum when the transformer is

a. star-delta

b. delta-star

c. delta-delta

d. star-star

Ans: ( b )

12. Transformer rating is expressed in

a. KVA


c. KW

Ans: ( a )

13. Manganin is a

a. Insulator

b. Semi-conductor

c. Alloy

14. Dual scope oscilloscope has

a. two separate horizontal and two separate vertical plates

b. one horizontal and two separate vertical plates

c. two separate horizontal and one vertical plates

d. one horizontal and one vertical plates

15. Standard Cell voltage is measured by

a. MI meter

b. MC meter

c. Potentiometer

16. The input resistance of the CRO is of the order of

a. tens of ohm

b. mega ohm

c. kilo ohm

d. fraction of an ohm

Ans: ( b )

17. Errors are introduced in Wheatstone bridge due to

a. lead resistance

b. contact resistance

c. some thing is given

d. all of the above

18. HRC fuse and circuit-breaker combination is used CB operates for

a. low over-load currents

b. high over-load currents

c. combination is never used

19. G(s) = K / s(s+5)(s+1) is given to find the value of K for stable operation

20. By increasing gain of the system root locus will

a. moves away from poles

b. moves away from zeros

c. crosses imaginary axis

Ans: ( a )

21. When the load current is high while measuring power using wattmeter

a. current coil is connected near load

b. pressure coil is connected near load

22. C = 0.01µF and L = 1 mH and current is 10 A and asked to find the voltage drop

23. Transmission line is terminated by R and no reflection is there , then the value of R is _________

Ans: 400 ohm

24. One question regarding shunt ohm-meter and seriea ohm-meter

25. Inverted V curves are drawn between ________

Ans: field current Vs power factor

26. Conductor size is based on ?
a) depeding upon the transmission line distance

Ans: might be ,a,

27. Which of the following transformers can be connecte in parallel

a) delta-delta, delta-star
b) delta-star , star-star
c) delta-delta , star-star
d) delta-star, star-delta

28. Compensating coil is connected in wat way in lpf wattmeter

Ans: around CC and in series with the PC

29. The input impedance is in the range of ____ in Digital Volt Meter

Ans: in Mega Ohm

30. The input and output impedance of an ideal opamp

31. Two resistances are connected in series and parallel manner..and the values of overall series and parallel connections is given and then asked to find out the two resistances.

32. Question on finding the power angle when the input to the generator is increased

33. Ferranti effect is obtained when?

Ans: when the sending voltage is less than receiving voltage

34. Which type of logic family used in

Ans: Emitter coupled Logic

35. When the temperature of the room increased then the energy of semiconductor…

36. Power diode is generally made from: - Silicon/Germanium/Both/None of these

37. Thermionic Emission of electron is due to………….

38. When the both junction of NPN diode is reverse biased, then the diode is in which mode: -

a) Active b) Cutoff c) Saturation d) inverted

39. Which transistor mode gives the inverted output: -

a) Common Emitter b) Common Base c) Common Collector d) None of these

40. Which coupling gives the higher gain in case of amplifier: -

a) Capacitor coupling b) Impedance coupling c) Transformer coupling

41. Which distortion is least objectionable in audio amplification: -

a) Phase b) Frequency c) Harmonic d) Intermediation

42 A narrowband amplifier has a band pass nearly…………of central frequency:-

a) 33.3% b) 10% c) 50%

43 Frequency of wein bridge oscillator

44. Phase shift oscillator consists: -

a) RL b) RC c) RLC

45. Crystal oscillator frequency is very stable due to:-

46. Multivibrater Produces: -

a) Sine wave b) Square wave c) Smooth wave d) sawtooth

47. Convert the 101101 Binary number into octal no: -

a) 65 b) 55 c) 51 d) 45

48. 10 in BCD: -

a) 10100 b) 1100 c) 010111 d) None of these

49. Which PNP device has a terminal for synchronizing purpose:-

a) SCS b) Triac c) Diac d) SUS

50. In 3-Phase full converter, the output during overlap is equal to……………..

51. Addition of indium in semiconductor crystal makes: -

a) PNP b) NPN

52. Free electron exists in which band: -

a) 1 b) 2 c) 3 d) Conduction band

53. Ripple factor of half wave rectifier: -

a) 1.21 b) 0.48 c) 0.5

54. The input and output impedance of an ideal opamp

55. Efficiency of half wave rectifier: -

56. Finding the power angel in power system

57. The motor used in fruit juicer

58. LVDT is used in finding th displacement

59 Cross magnetization will come with wat pf

60. The type of converter used in HVDC

61. The relationship b/w the airgap and current in light

62. Corrona loss is less in which type of shaped conductor?( the question is asked 2 times)

Ans: circular

63.The motor used in low speed applications?

64. If the accuracy of an instrument is 5% for 100A current ,accuracy for 50A current?

65 A question on time constant of a coil(R-L) circuit!

66. Effect of line commutated inductance in inverter

a) increase current ripple
b) reduces current ripple
c) increases output voltage
d) reduces output voltage

67. The type of bridge is used for Low Q applications

ans: maxwells bridge

68. A question on PSM and TSM in power system

69. The advantage of PI controller over P controller

70. The power gain is highest in wat amplifier

Ans : common emitter

71. Power of a converter with ac input supply and dc output current


72. The element which has unchanged properties when current direction is reversed

Ans: b

73. The output voltage is high in wat rectifier

a) HWR
b) FWR

HAL Placement Paper : HAL Placement Paper Aeronautical Eng questions 25 April 2011

Hal Paper

Diploma Trainee (Electronics) Exam Held on 26th April 2011

General Knowledge :- 30 Questions

Electronics :- 70 Questions
I :- General Knowledge
1. Lucknow is popular for which fruit: -
a) Mango b) Orange c) Water fruit
2. Governor of utter Pradesh
3. President of India
4. In which district of UP a oil refinery is found
5. Pigeon is the indication of
6. The chemical Formula of salt
7. Republic day in India is celebrated on
8. The “Beating the retreat” hasn’t celebrated on republic day, what is its resion…
9. Lucknow city is located near which river
10. Firozabad is popular for
11. Renukot is popular for
12. The first prime minister of India
13. The first President of India
14. The birth day of Pandit Jawahar Lal Nehru is celebrated as:-
15. The writer of ‘Godan’
16. Word ‘Agfa’ is related to:--

II:- Electronics Questions.

1. When the temperature of the room increased then the energy of semiconductor…

2. Power diode is generally made from: - Silicon/Germanium/Both/None of these

3. Thermionic Emission of electron is due to………….

4. When the both junction of NPN diode is reverse biased, then the diode is in which mode: -
a) Active b) Cutoff c) Saturation d) inverted

5. Which transistor mode gives the inverted output: -
a) Common Emitter b) Common Base c) Common Collector d) None of these

6. Which coupling gives the higher gain in case of amplifier: -
a) Capacitor coupling b) Impedance coupling c) Transformer coupling

7. Which distortion is least objectionable in audio amplification: -
a) Phase b) Frequency c) Harmonic d) Intermediation

8. A narrowband amplifier has a band pass nearly…………of central frequency:-
a) 33.3% b) 10% c) 50%

9. Frequency of wein bridge oscillator

10. Phase shift oscillator consists: -
a) RL b) RC c) RLC

11. Crystal oscillator frequency is very stable due to:-

12. Multivibrater Produces: -
a) Sine wave b) Square wave c) Smooth wave d) sawtooth

13. Convert the 101101 Binary number into octal no: -
a) 65 b) 55 c) 51 d) 45

14. 10 in BCD: -
a) 10100 b) 1100 c) 010111 d) None of these

15. Which PNP device has a terminal for synchronizing purpose:-
a) SCS b) Triac c) Diac d) SUS

16. In 3-Phase full converter, the output during overlap is equal to……………..

17. Addition of indium in semiconductor crystal makes: -
a) PNP b) NPN

18. Free electron exists in which band: -
a) 1 b) 2 c) 3 d) Conduction band

19. Ripple factor of half wave rectifier: -
a) 1.21 b) 0.48 c) 0.5

20. Efficiency of half wave rectifier: -

21. Transistor that can be used in enhancement mode:-

21. Following contributes to harmonic distortion in Amplifier: -
a) +Ve feedback b) –Ve feedback c) Defective active device

22. High cutoff frequency: -
a) CB b) CC c) CE

23. Which is used as data selector?
a) Encoder b) Decoder c) modulator d) Demodulator

24. Read write capable memory: -
a) RAM b) ROM c) Both d) None of these

25. When modulation frequency is doubled, modulation index also doubled in case of: -
a) FM b) PM c) AM d) PM & FM

26. Term ’Noise temperature’ is used for

27. Video detector used in TV receiver is a….
a) Diode detector b) Ratio detector c) Phase detector

28. Which isn’t directly operated from mains: -
a) Half wave rectifier b) Centre tap rectifier c) Bridge rectifier d) Voltage doubler

29. In 3-Phase half wave rectifier each diode conducts for duration of: -
a) 30 Degree b) 45 Degree c) 60 Degree d) 180 Degree

30. If number of phase in a multiphase rectifier increased then: -
a) Output increased b) Output decreased c) Output smooth d) No change

31. Which output requires minimum filtration: -
a) Half wave rectifier b) full wave c) SCR half wave rectifier d) Voltage doubler

32. Identify the under circuit
a) Low pass filter b) High pass filter c) Band pass filter

33. Transistor is a following operated device: -
a) Low voltage & low current device
b) Low voltage & high current device
c) Low current & high voltage device
d) High current & high voltage device

HAL Placement Paper : Test Pattern


·         Kindly appear for the Written Test on the specified Date and  Time  at the allotted Test Venue.

·         Make sure that you occupy the allotted seat at the Test Venue by 0950 hours, which will be displayed on the Notice Board.

·         Candidates are required to bring  any proof of their identity having their photograph viz Passport, Voters’ ID Card, Driving License, ID Card issued by the Academic Institution last attended etc., for verification, when they come for the Written Test. The Admit Card shall be signed by the Candidates in the presence of the Invigilator. Candidates should affix their passport size photograph on the Admit Card.

·         Candidates have to ensure that they return the Admit Card, OMR Answer Sheet and the Question Booklet  to the Invigilator  after the Written Test, failing which their candidature shall be cancelled.

·         The Question Booklets  are  broadly classified into five Disciplines as indicated below: 

      1)    Aeronautical
2)     Mechanical and Production
3)    Metallurgy
4)    Electrical and Electronics
5)    Computer Science 

·         Each Question Booklet will have 160 Objective Type Questions, as indicated below: 

General Awareness

(15 Questions)

General Engineering

(25 Questions)

Questions specific to the respective Disciplines indicated above (120 Questions)


(160 Questions)

15 Marks

25 Marks

120 Marks

160 Marks


1.      The Question Booklet  for Mechanical and Production Disciplines will be the same and candidates will have to answer questions for both Mechanical and Production Branches.

2.      The Question Booklet  for Electrical and Electronics Disciplines will be the same and candidates will have to answer questions for both Electrical and Electronics Branches. 

·         There are no negative marks for incorrect answers.

·         Please use  the blank pages provided at the end of the Question Booklet only for any rough work.

·         If any Candidate is  found to be indulging in any kind of malpractice like copying, trying to talk to other candidates, exchanging information, carrying/passing on chits of paper or any other mode to communicate with others,  his/her candidature shall be cancelled.

·         Mobile Phones, Pagers, Beepers, any kind of Audio Devices, Digital Diaries, Organisers etc., shall not be permitted inside the Examination Hall.

·         Candidates will be required to appear for the Written Test at their own expense and will have to make their own arrangements for boarding and lodging at the place of the Examination.

·         Further consideration of the candidature after the Written Test  will be subject to:- 

1.      Candidates having passed the final Engineering Examination in the specified Branches of Engg. indicated in the Advertisement, from any recognised Institution/University, with 60% marks in the Aggregate of all Semesters for General/OBC and 50% Marks in the aggregate of all Semesters for SC/ST Candidates.

2.      Verification of  Qualifications, Marks scored, Age, Caste (for SC/ST/OBC      only), PWD   (Person with Disability) /Ex-Servicemen etc. 


Candidates must ensure that they are in possession of the following documents/items, when they report at the Examination Centre:

·         Admit Card (with Passport Size photograph duly affixed).

·         Proof of Identity having their photograph such as Passport, Voters’ ID Card, Driving License, ID Card issued by the Academic Institution last attended etc.,  for verification by the Invigilator.

·         HB Pencils, Eraser, Pen and  Calculator.


  1. Use only HB Pencil  to  mark the Ovals  in the Answer Sheet.  
  1. Use Ball Point Pen  to  fill the Boxes  (ie for the Question Booklet No., Roll Number, Date of Birth and Signature.) 
  1. Indicate  the Question Booklet Series and Question Booklet Serial Number in the  space  provided on the OMR Answer Sheet without fail.  
  2. Please mark the relevant Ovals against the columns like Series, Category, Quota and Main Branch of Engineering as applicable to you.
  3. Mark your answer only in the appropriate space against the Number corresponding to the question you are  answering. Darken the response for each question:  

                                                A        B          C            D

                                        (ie., if the  answer to the Question is option A , then it needs to be darkened )  

6.  Please ensure that the Ovals are completely darkened.

  1. In case of any mistake while marking, please erase the mark completely and fill the correct Oval  again. Do not leave stray marks/half filled Ovals on the Answer Sheet.
  2. Rough work must not be done on the Answer Sheet.  Use the blank pages  given at the end of the Question Booklet for rough work.   

HAL Placement Paper : General - other Manipal Learning Institute,Hyderabad - 25 November 2007


hi friends, the written test contains 160 q,20 on English,10 on aptitude ,10 on general awareness,remaining 120 related to subject.all r multiplechoice -ve marking.

mainly concentrate on "tense " and spellings,one passage is there,it is also some wht easy.

mostly from profit and loss,trains,avg.

3.general awareness:
1 .  who won the academy award in the year 2006?
2 . who played the role of Gandhi in the movie Mahatma Gandhi?
3. Agni-iii was launched in which year?

I am from mechanical engineering. mainly the questions r frm theory of machines(Gears,Gyroscopes,Cams),Thermodynamics(second law,heat transfer), manufacturung technology. so throughly prepare all these sub. i hav cleared written.

i attended interview in banglore on 8th dec.
In interview all questions r frm basics.
first they asked which sub u like most?
i said thermodynamics.
some of the quest...
1. wht is first law?
2.wht r various types of heat transfers? wht is convectoin?
3.wht is blackbody radiation?
4wht is absorbvity,emissivity?
5 wht is mechanism?
draw the fig of quick return mechanism?
6.some questions regarding gears

HAL Placement Paper : Whole Testpaper All Saints High Schol ,Hyderbad - 28 October 2007


Hi every i gave HAL written test in hyderbad in ELECTRONICS branch there are 145 technical questions and 15 general studies the very very very very very important thing for those who apearing for HAL exam in electronics is they are given most of the questions from DC MECHINES nearly 50 quetions from that subject today i was shocked to see ques,s from that subject,so pls concentrate more on dc mechines.

mostly they are given questions from these subjects
1.dc mechines(about 50)
3.instruments(5) electronics(30)
5.EDC & analog electronics (8)
6.control systems(2)
7.antenas,satillite commincation(5)
the paper is very hard i dont expect they will give question patern like this so plz concentrate more on mechines
some of questions i feel easy and i remember are 
1.what is weight of 5rupee coin??
2.who is below never a cheif justice of india ?
3.what is largest ISRO company in india?
4.who is player took 10 wikts in one test innings ?
(in the list anil kumble not given) 

techinical que,s:
1.binary number for 1001.1101?
2.decimal number for 19?
3.excess-3 code for 29?
4.speed-torque characterictics of dc motor?
(some figures given)
5.quantization noise occurs in??(repeated question 2 times given)
6.schering brige method used for measuring of??
7.prom based on networks are very very easy every body can calculate curent in one resistor if  10 resistors are connected in parall like that
8.if speed doubles,distance increases what is the torque in dc motor?
9.what is the value of  A,+1 ?
10.what is instrument used in MIC instrument?
 a)galvonometer b)ammeter like that....
11.question about dammping concept in PMMC
12.what is PAL full form??
13.what is the use for sweeping resistor in transistor??
14.quetion based on bootstraping concept.
15.rms current in half wave rectifier?
16.what is form factor?(some ratios are given)
17.prob on tree branches concept
18.range of radio telemetry...some frequencies given
so these are questins which are very very easy and i remembered
dont feel happy to see these questions in every exam these type easy questins they will give but
who gave corect answers to difficult questions he only will select in written do hard work better to learn concept clearly now a days this galgotia book also not useful for p.s.u,s
prepare test books more.....

HAL Placement Paper : HAL Paper General - other


HI friends i am ASHISH BHUIYA, done my BE from BHOPAL (ALL SAINTS, COLLEGE OF TECHNOLOGY). I  was appear for the post of magmt. tranee in last 20th may 2007,from the branch EC 


  1. Technical 100 question
  2. Apptitude 40 question
  3. Genral English 20 question
  • Dicription of technical paper-their was around 30 question from core elctronics on diod,transistor,amplifire,filters,dc characterstics of transistor,FET,MOSFET,JFET,rctifire eficiecny,op-amp-summer,diff.,integrator,que. on characterstic of op-amp,4-5 question on core communication AM,DSBSC,SSBSC,FSK,QPSK(probility of error),datarate of DM,que. on quantization error and some conceptiual que. and all this thing read from ELECTRONICS-sedra&smit, comm. system by simyon hakin,milman hallkas,sorry 4 spelling mistake
  • Discription of 10-15 questio from network analysis simple question,ask on abcd ,yparameter,z parameter,n/w theorem,initial condition,10-12 que. from 12th class physics basd on equipotentiol surface,dipole,columb rule
  • 10-12 que on digital ckt system based on nand,nor ,and gate,some direct question based on ADC&DAC around 3-4 que
  • 10-12 quetion based on control system from,gain,frequencyresponce,time response ie routharry,bode plot,rotlocus,plor plot,RELATION b/n physical and electic fn.
  • 10-12 question on 12th class maths including continuty,integration,diff. question.
  • 3-5 question on BE maths
  • question from section APPTITUDE is completly copyed from BS AGRAWAL each qus. from every topic don,t forgett to do it
  • eng from anseen passage,then question,synonims,opposite words.
  • 80% mark of theory paper,20% for interviwe so u hav to go for kill in written exam. friends.

HAL Placement Paper : HAL Paper Whole Testpaper Hyderabad - 20 May 2007


1 synchro tc and rx is

a )   two phase ac

b)    three phase ac

c)    dc only

d)    none


2 in 4 bit number one bit indicates sign of the number then the locations are from

a)      -8 to 8

b)      -7 to 7

c)      -16 to 16

d)      None


3  G(s) = 10/S(S+2) then the natural frequency of this transfer function is

a)      3.146

b)      4

c)      5

d)      2


4  In TV video amplifier is used for  =?


5) one block  contain one of the R L C element then the frequency of that one is 1 MHZ when the capacitor C= 0.1 uf is added to that block then the frequency becomes 2 MHZ then what is the element inside the block at first time

a) resistor

b) inductor

c) capacitor with 0.5 uf

d) none of these

ans : b


6) For unit step input they gave the input G(S)= - -- - - -,h(s)= -------then he ask the steady state error for that transfer fn


7)Avalanche photo diode is used when compared to PIN diode bcz

 a) larger band width      C)-------

 b) high sensitivity          d) --------


8)  some non zero DC voltage is      to RC low pass circuit then the DC voltage in the output contains

a)      Same as in input

b)      Higher than  input

c)      Zero

d)      Slightly increases

9) ifthe output of the gate is always high then the gates applied to this logic are

a)      NAND and EXOR

b)      Nand and NOR

c)      AND and XNOR

d)      OR and XOR

Ans ) a


10) For the voltage series feedback he gave input resistance and A  and beta value then find the output resistance ?


11)Signal to noise ratio =15 db Bandwidth =4KHZ then the channel capacity -?

Ans :                C= B Log (1+ s/n)   =16 log 2

12 ) Four  messages are given like this 0.5,0.25,0.125,0.125 ,entrophy value is =?

Ans:          Entrophy= Avg of all informations


13) Thermal Run away is not possible in FET bcz the flow of

a)      minority careers        c) _____

b)      Transconductance      d) none

Ans : FET is unipolar so there are no minority careers .Thermal run away occurs only minority careers


14)Gm= 10 ,Rd =20k,Rl =10 find the amplification factor -=?

Ans =  U= Gm Rd


15)  Two ideal voltage sourd=ces resistors are connected in series ,power of that one is 4W ,If one of the sorce is active other resistors are shorted .Calculate the power when both are active +/

a)      0W,8W

b)      8W,6W

c)      4W,0W

d)      None


16)   A TV braod cast tx uses which type of antenna =?

a) parabolic antenna b)=---

c)-----   d) -----

ans : a


17)   Electric field and equi potential lines are

a) parallel to each other

b) In Quadrature

ans : b

18 ) L1= ----- , L2 =  ---- k= _---- then mutual inductance of the coil is =?

Ans :    M=ksquare root of L!and L2


19 ) one cube some is there to find out the how many number of cubes are having single side ?


20)Two qs in verbal are ----- two statements are given for that the relation btwn those two

Totally there are 160 qs out of that 100 qs from technical and 60 qs from aptitudeand verbal

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