136 TOP Engineering Mechanics - Mechanical Engineering Multiple choice Questions and Answers Latest Engineering Mechanics Questions and Answers List

Engineering Mechanics Objective type Questions and Answers

1. The unit of force in S.I. units is
(a) kilogram
(b) newton
(c) watt
(d) dyne
(e) joule.
Ans: b
2. The unit of work or energy in S.I. units is
(a) newton
(b) pascal
(c) kilogram meter
(d) watt
(e) joule.
Ans: e
3. The unit of power in S.I. units is
(a) newton meter
(b) watt
(c) joule
(d) kilogram meter/sec.
(e) pascal per sec.
Ans: b
4. Forces are called concurrent when their lines of
action meet in
(a) one point
(b) two points
(c) plane
(d) perpendicular planes
(e) different planes.
Ans: a
5. Forces are called coplanar when all of them
acting on body lie in
(a) one point
(b) one plane
(c) different planes
(d) perpendicular planes
(e) different points.
Ans: b
6. A force acting on a body may
(a) introduce internal stresses
(b) balance the other forces acting on it
(c) retard its motion
(d) change its motion
(e) all of the above.
Ans: e
7. Which is the correct statement about law of
polygon of forces ?
(a) if any number of forces acting at a point can be
represented by the sides
of a polygon taken in order, then the forces are in
equilibrium
(b) if any number of forces acting at a point can be
represented in direction and magnitude by the sides
of a polygon, then the forces are in equilibrium
(c) if a polygon representing forces acting at a point
is closed then forces are in equilibrium
(d) if any number of forces acting at a point can be
represented in direction and magnitude by the sides
of a polygon taken in order, then the forces are in
equilibrium
(e) none of the above.
Ans: d
8. Effect of a force on a body depends upon
(a) magnitude
(b) direction
(c) positionor line of action
(d) all of the above
(e) none of the above.
Ans: d
9. If a number of forces act simultaneously on
a particle, it is possible
(a) not a replace them by a single force
(b) to replace them by a single force
(c) to replace them by a single force through C.G.
(d) to replace them by a couple
(e) to replace them by a couple and a force.
Ans: b
11. A force is completely defined when we specify
(a) magnitude
(b) direction
(c) point of application
(d) all of the above
(e) none of the above.
Ans: d
12. If two equal forces of magnitude P act at an
angle 9°, their resultant will be
(a) P/2 cos 9/2
(b) IP sin 9/2
(c) 2P tan 9/2
(d) IP cos 9/2
(e) Psin 9/2.
Ans: d
13. The algebraic sum of the resolved parts of a
number of forces in a given direction is equal to the
resolved part of their resultant in the same
direction. This is as per the principle of
(a) forces
(b) independence of forces
(c) dependence of forces
(d) balance of force
(e) resolution of forces.
Ans: e
14. The resolved part of the resultant of two forces
inclined at an angle 9 in a given direction is equal to
(a) the algebraic sum of the resolved parts of the
forces in the given direction
(b) the sum of the resolved parts of the forces in
the given direction
(c) the difference of the forces multiplied by the
cosine of 9
(d) the sum of the forces multiplied by the sine of 9
(e) the sum of the forces multiplied by the tangent of
9.
Ans: a
15. Which of the following do not have identical
dimensions ?
(a) Momentum and impulse
(b) Torque and energy
(c) Torque and work
(d) Kinetic energy and potential energy
(e) Moment of a force and angular momentum.
Ans: e
16. Which of the following is not the unit of
distance ?
(a) angstrom
(b) light year
(c) micron
(d) millimetre
(e) milestone.
Ans: e
17. Which of the following is not the unit of power ?
(a) kW (kilowatt)
(b) hp (horse power)
(c) kcal/sec
(d) kg m/sec
(e) kcal/kg sec.
Ans: e
18. Which of the following is not the unit of work,
energy and heat ?
(a) kcal
(b) kg m
(c) kWhr
(d) hp
(e) hp hr.
Ans: d
19. Which of the following is not the unit of
pressure ?
(a) kg/cm
(b) ata
(c) atmosphere
(d) mm of wcl
(e) newton.
Ans: e
20. The weight of a body is due to
(a) centripetal force of earth
(b) gravitational pull exerted by the earth
(c) forces experienced by body in atmosphere
(d) force of attraction experienced by particles
(e) gravitational force of attraction towards the
center of the earth.
Ans: e
21. The forces, which meet at one point, but their
lines of action do not lie in a plane, are called
(a) coplanar non-concurrent forces
(b) non-coplanar concurrent forces
(c) non-coplanar non-concurrent forces
(d) intersecting forces
(e) none of the above.
Ans: b
22. When trying to turn a key into a lock, following is
applied
(a) coplanar force
(b) non-coplanar forces
(c) lever
(d) moment
(e) couple.
Ans: e
23. Which of the following is not a scalar quantity
(a) time
(b) mass
(c) volume
(d) density
(e) acceleration.
Ans: e
24. According to principle of transmissibility of
forces, the effect of a force upon a body is
(a) maximum when it acts at the center of gravity of
a body
(b) different at different points in its line of action
(c) the same at every point in its line of action
(d) minimum when it acts at the C.G. of the body
(e) none of the above.
Ans: c
25. Which of the following is a vector quantity
(a) energy
(b) mass
(c) momentum
(d) angle
(e) speed.
Ans: c
26. The magnitude of two forces, which when acting
at right angle produce resultant force of VlOkg and
when acting at 60° produce resultant of Vl3 kg.
These forces are
(a) 2 and V6
(b) 3 and 1 kg
(c) V5andV5
(d) 2 and 5
(e) none of the above.
Ans: c
27. A number of forces acting at a point will be in
equilibrium if
(a) their total sum is zero
(b) two resolved parts in two directions at right
angles are equal
(c) sum of resolved parts in any two per-pendicular
directions are both zero
(d) all of them are inclined equally
(e) none of the above.
Ans: c
28. Two non-collinear parallel equal forces acting in
opposite direction
(a) balance each other
(b) constitute a moment
(c) constitute a couple
(d) constitute a moment of couple
(e) constitute a resultant couple.
Ans: c
29. According to principle of moments
(a) if a system of coplanar forces is in equilibrium,
then their algebraic sum is zero
(b) if a system of coplanar forces is in equilibrium,
then the algebraic sum of their moments about any
point in their plane is zero
(c) the algebraic sum of the moments of any two
forces about any point is equal to moment of
theiwesultant about the same point
(d) positive and negative couples can be balanced
(e) none of the above.
Ans: b
30. Which of the following is not a vector quantity
(a) weight
(b) velocity
(c) acceleration
(d) force
(e) moment.
Ans: a
31. According to law of triangle of forces
(a) three forces acting at a point will be in
equilibrium
(b) three forces acting at a point can be represented
by a triangle, each side being proportional to force
(c) if three forces acting upon a patticle are
represented in magnitude and direction by the sides
of a triangle, taken in order, they will be in
equilibrium
(d) if three forces acting at a point are in
equilibrium, each force is proportional to the sine of
the angle between the other two
(e) none of the above.
Ans: c
33. If a rigid body is in equilibrium under the action
of three forces, then
(a) these forces are equal
(b) the lines of action of these forces meet in a point
(c) the lines of action of these forces are parallel
(d) (b) and (c) above
(e) none of the above.
Ans: d
34. D' Alembert's principle is used for
(a) reducing the problem of kinetics to equivalent
statics problem
(b) determining stresses in the truss
(c) stability of floating bodies
(d) designing safe structures
(e) solving kinematic problems.
Ans: a
35. A heavy ladder resting on floor and against a
vertical wall may not be in equilibrium, if
(a) the floor is smooth, the wall is rough
(b) the floor is rough, the wall is smooth
(c) the floor and wall both are smooth surfaces
(d) the floor and wall both are rough surfaces
(e) will be in equilibrium under all conditions.
Ans: c
38. According to Lami's theorem
(a) three forces acting at a point will be in
equilibrium
(b) three forces acting at a point can be represented
by a triangle, each side being proportional to force
(c) if three forces acting upon a particle are
represented in magnitude and
direction by the sides of a triangle, taken in order,
they will be in equilibrium
(d) if three forces acting at a point are in
equilibrium, each force is proportional to the sine of
the angle between the other two
(e) none of the above.
Ans: d
39. Two coplanar couples having equal and opposite
moments
(a) balance each other
(b) produce a couple and an unbalanced force
(c) are equivalent
(d) produce a moment of couple
(e) can not balance each other.
Ans: e
40. A framed structure is perfect if it contains
members equal to
(a) 2n-3
(b) n-l
(c) '2n-l
(d) n - 2
(e) 3n-2.
where n = number of joints in a frame
Ans: a
42. The product of either force of couple with the
arm of the couple is called
(a) resultant couple
(b) moment of the forces
(c) resulting couple
(d) moment of the couple
(e) none of the above.
Ans: d
43. In detennining stresses in frames by methods of
sections, the frame is divided into two parts by an
imaginary section drawn in such a way as not to cut
more than
(a) two members with unknown forces of the frame
(b) three members with unknown forces of the
frame
(c) four members with unknown forces of the frame
(d) three members with known forces of the frame
(e) four members with two known forces.
Ans: b
44. The center of gravity of a uniform lamina lies at
(a) the center of heavy portion
(b) the bottom surface
(c) the mid point of its axis
(d) all of the above
(e) none of the above.
Ans: c
45. Center of gravity of a solid cone lies on the axis
at the height
(a) one-fourth of the total height above base
(b) one-third of the total height above base
(c) one-half of the total height above base
(d) three-eighth of the total height above the base
(e) none of the above.
Ans: a
46. Center of percussion is
(a) the point of C.G.
(b) the point of metacentre
(c) the point of application of the resultant of all the
forces tending to cause a body to rotate about a
certain axis
(d) point of suspension
(e) the point in a body about which it can rotate
horizontally and oscillate under the influence of
gravity.
Ans: c
47. Center of gravity of a thin hollow cone lies on
the axis at a height of
(a) one-fourth of the total height above base
(b) one-third of the total height above base
(c) one-half of the total height above base
(d) three-eighth of the total height above the base
(e) none of the above.
Ans: b
48. The units of moment of inertia of an area are
(a) kg m2
(b) m4
(c) kg/m2
(d) m3
(e) kg/m4.
Ans: b
49. The center of percussion of the homogeneous
rod of length L suspended at the top will be
(a) L/2
(b) L/3
(c) 3L/4
(d) 2L/3
(e) 3L/8.
Ans: d
50. The center of gravity of a triangle lies at the
point of
(a) concurrence of the medians
(b) intersection of its altitudes
(c) intersection of bisector of angles
(d) intersection of diagonals
(e) all of the above.
Ans: a
51. The units of moment of inertia of mass are
(a) kg m2
(b) m4
(c) kg/m2
(d) kg/m
(e) m2/kg.
Ans: a
52. The possible loading in various members of
framed structures are
(a) compression or tension
(b) buckling or shear
(c) shear or tension
(d) all of the above
(e) bending.
Ans: a
53. A heavy string attached at two ends at same
horizontal level and when central dip is very small
approaches the following curve
(a) catenary
(b) parabola
(c) hyperbola
(d) elliptical
(e) circular arc.
Ans: b
54. A trolley wire weighs 1.2 kg per meter length.
The ends of the wire are attached to two poles 20
meters apart. If the horizontal tension is 1500 kg
find the dip in the middle of the span
(a) 2.5 cm
(b) 3.0 cm
(c) 4.0 cm
(d) 5.0 cm
(e) 2.0 cm.
Ans: c
55. From a circular plate of diameter 6 cm is cut out
a circle whose diameter is a radius of the plate.
Find the e.g. of the remainder from the center of
circular plate
(a) 0.5 cm
(b) 1.0 cm
(c) 1.5 cm
(d) 2.5 cm
(e) 0.25 cm.
Ans: a
58. Pick up the incorrect statement from the
following :
(a) The C.G. of a circle is at its center
(b) The C.G. of a triangle is at the intersection of
its medians
(c) The C.G. of a rectangle is at the inter-section of
its diagonals
(d) The C.G. of a semicircle is at a distance of r/2
from the center
(e) The C-G. of an ellipse is at its center.
Ans: d
59. The center of percussion of a solid cylinder of
radius r resting on a horizontal plane will be
(a) r/2
(b) 2r/3
(c) r/A
(d) 3r/2
(e) 3r/A.
Ans: d
62. In the equation of virtual work, following force is
neglected
(a) reaction of any smooth surface with which the
body is in contact
(b) reaction of a rough surface of a body which rolls
on it without slipping
(c) reaction at a point or an axis, fixed in space,
around which a body is con-strained to turn
(d) all of the above
(e) none of the above.
Ans: d
63. If a suspended body is struck at the center of
percussion, then the pressure on die axis passing
through the point of suspension will be
(a) maximum
(b) minimum
(c) zero
(d) infinity
(e) same as the force applied.
Ans: c
65. The resultant of the following three couples 20
kg force, 0.5 m arm, $ ve sense 30 kg force, 1 m
arm, - ve sense 40 kg force, 0.25 m arm, + ve
sense having arm of 0.5 m will be
(a) 20 kg, - ve sense
(b) 20 kg, + ve sense
(c) 10 kg, + ve sense
(d) 10 kg, - ve sense
(e) 45 kg, + ve sense.
Ans: a
68. Angle of friction is the
(a) angle between normal reaction and the
resultant of normal reaction and the limiting friction
(b) ratio of limiting friction and normal reaction
(c) the ratio of minimum friction force to the
friction force acting when the body is just about to
move
(d) the ratio of minimum friction force to friction
force acting when the body is in motion
(e) ratio of static and dynamic friction.
Ans: a
69. The coefficient of friction depends on
(a) area of contact
(b) shape of surfaces
(c) strength of surfaces
(d) nature of surface
(e) all of the above.
Ans: d
70. Least force required to draw a body up the
inclined plane is W sin (plane inclination + friction
angle) applied in the direction
(a) along the plane
(b) horizontally
(c) vertically
(d) at an angle equal to the angle of friction to the
inclined plane
(e) unpredictable.
Ans: d
71. The ratio of limiting friction and normal reaction
is known as
(a) coefficient of friction
(b) angle of friction
(c) angle of repose
(d) sliding friction
(e) friction resistance.
Ans: a
72. Which one of the following statements is not
correct
(a) the tangent of the angle of friction is equal to
coefficient of friction
(b) the angle of repose is equal to angle of friction
(c) the tangent of the angle of repose is equal to
coefficient of friction
(d) the sine of the angle of repose is equal to
coefficient to friction
(e) none of the above.
Ans: d
73. On a ladder resting on smooth ground and
leaning against vertical wall, the force of friction will
be
(a) towards the wall at its upper end
(b) away from the wall at its upper end
(c) upwards at its upper end
(d) downwards at its upper end
(e) none of the above.
Ans: c
74. On the ladder resting on the ground and leaning
against a smooth vertical wall, the force of friction
will be
(a) downwards at its upper end
(b) upwards at its upper end
(c) perpendicular to the wall at its upper end
(d) zero at its upper end
(e) none of the above.
Ans: d
76. Frictional force encountered after
commencement of motion is called
(a) post friction
(b) limiting friction
(c)  kinematic friction
(d) frictional resistance
(e) dynamic friction.
Ans: e
77. Coefficient of friction is the
(a) angle between normal reaction and the resultant
of normal reaction and the limiting friction
(b) ratio of limiting friction and normal reaction
(c) the friction force acting when the body is just
about to move
(d) the friction force acting when the body is in
motion
(e) tangent of angle of repose.
Ans: b
78. Pick up wrong statement about friction force for
dry surfaces. Friction force is
(a) proportional to normal load between the
surfaces
(b) dependent on the materials of contact surface
(c) proportional to velocity of sliding
(d) independent of the area of contact surfaces
(e) none of the above is wrong statement.
Ans: c
79. A body of weight W on inclined plane of a being
pulled up by a horizontal force P will be on the point
of motion up the plane when P is equal to
(a) W
(b) W sin (a + $)
(c) Wtan(a + <|))
(d) W\an(a-<t>)
(e) Wtana.
Ans: c
80. A particle moves along a straight line such that
distance (x) traversed in t seconds is given by x =
t2 (t - 4), the acceleration of the particle will be
given by the equation
(a) 3t2-lt
(b) 3t2+2t
(c) 6f-8
(d) 6f-4
(e) 6t2-8t.
Ans: c
81. If rain is falling in the opposite direction of the
movement of a pedestrain, he has to hold his
umbrella
(a) more inclined when moving
(b) less inclined when moving
(c) more inclined when standing
(d) less inclined when standing
(e) none of the above.
Ans: d
86. A projectile is fired at an angle 9 to the vertical.
Its horizontal range will be maximum when 9 is
(a) 0°
(b) 30°
(c) 45°
(d) 60°
(e) 90°.
Ans: c
88. Limiting force of friction is the
(a) tangent of angle between normal-reaction and
the resultant of normal reaction and limiting friction
(b) ratio of limiting friction and normal reaction
(c) the friction force acting when the body is just
about to move
(d) the friction force acting when the body is in
motion
(e) minimum force of friction.
Ans: c
89. Coulomb friction is the friction between
(a) bodies having relative motion
(b) two dry surfaces
(c) two lubricated surfaces
(d) solids and liquids
(e) electrically charged particles.
Ans: a
90. Dynamic friction as compared to static friction
is
(a) same
(b) more
(c) less
(d) may be less of more depending on nature of
surfaces and velocity
(e) has no correlation.
Ans: c
92. Tangent of angle of friction is equal to
(a) kinetic friction
(b) limiting friction
(c) angle of repose
(d) coefficient of friction
(e) friction force.
Ans: d
93. Kinetic friction is the
(a) tangent of angle between normal reaction and
the resultant of normal reaction and the limiting
friction
(b) ratio of limiting friction and normal reaction
(c) the friction force acting when the body is just
about to move
(d) the friction force acting when the body is in
motion
(e) dynamic friction.
Ans: d
95. The effort required to lift a load W on a screw
jack with helix angle a and angle of friction <j) is
equal to
(a) Wtan(a + <)>)
(b) Wtan(a-<)>)
(c) Wcos(a + <t>)
(d) Wsin(a + <(>)
(e) W (sin a + cos <j>).
Ans: a
96. A semi-circular disc rests on a horizontal
surface with its top flat surface horizontal and
circular portion touching down. The coefficient of
friction between semi-cricular disc and horizontal
surface is \i. This disc is to be pulled by a horizontal
force applied at one edge and it always remains
horizontal. When the disc is about to start moving,
its top horizontal force will
(a) remain horizontal
(b) slant up towards direction of pull
(c) slant down towards direction of pull
(d) unpredictable
(e) none of the above.
Ans: c
97. A particle inside a hollow sphere of radius r,
having coefficient of friction -rr can rest upto height
of
(a) r/2
(b) r/A
(c) r/%
(d) 0.134 r
(e) 3r/8.
Ans: d
98. The algebraic sum of moments of the forces
forming couple about any point in their plane is
(a) equal to the moment of the couple
(b) constant
(c) both of above are correct
(d) both of above are wrong
(e) none of the above.
Ans: a
99. A single force and a couple acting in the
same plane upon a rigid body
(a) balance each other
(b) cannot balance each other
(c) produce moment of a couple
(d) are equivalent
(e) none of the above.
Ans: b
100. If three forces acting in one plane upon a rigid
body, keep it in equilibrium, then they must either
(a) meet in a point
(b) be all parallel
(c) at least two of them must meet
(d) all the above are correct
(e) none of the above.
Ans: d
101. The maximum frictional force which comes
into play when a body just begins to slide over
another surface is called
(a) limiting friction
(b) sliding friction
(c) rolling friction
(d) kinematic friction
(e) dynamic friction.
Ans: a
102. The co-efficient of friction depends upon
(a) nature of surfaces
(b), area of contact
(c) shape of the surfaces
(d) ail of the above.
(e) (a) and (b) above.
Ans: a
104. The necessary condition for forces to be in
equilibrium is that these should be
(a) coplanar
(b) meet at one point ;
(c) both (a) and (b) above
(d) all be equal
(e) something else.
Ans: c
105. If three forces acting in different planes can be
represented by a triangle, these will be in
(a) non-equilibrium
(b) partial equilibrium
(c) full equilibrium
(d) unpredictable
(e) none of the above.
Ans: a
106. If n = number of members andy = number of
joints, then for a perfect frame, n =
(a) j-2
(b) 2j-l
(c) 2/-3
(d) 3/-2
(e) 2/ -4.
Ans: c
107. A body moves, from rest with a constant
acceleration of 5 m per sec. The distance covered
in 5 sec is most nearly
(a) 38 m
(b) 62.5 m
(C) 96 m
(d) 124 m
(e) 240 m.
Ans: b
108. A flywheel on a motor goes from rest to 1000
rpm in 6 sec. The number of revolutions made is
nearly equal to
(a) 25
(b) 50
(c) 100
(d) 250
(e) 500.
Ans: b
109. Which of the following is the locus of a point
that moves in such a manner that its distance from
a fixed point is equal to its distance from a fixed line
multiplied by a constant greater than one
(a) ellipse
(b) hyperbola
(c) parabola
(d) circle
(e) none of the above.
Ans: b
111. Which of the following is not the unit of energy
(a) kg m
(b) kcal
(c) wattr
(d) watt hours
(e) kg m x (m/sec)2.
Ans: c
112. A sample of metal weighs 219 gms in air, 180
gms in water, 120 gms in an unknown fluid. Then
which is correct statement about density of metal
(a) density of metal can't be determined
(b) metal is twice as dense as water
(c) metal will float in water
(d) metal is twice as dense as unknown fluid
(e) none of the above.
Ans: a
113. The C.G. of a solid hemisphere lies on the
central radius 3r
(a) at distance — from the plane base 3r
(b) at distance — from the plane base 3r
(c) at distance — from the plane base 3r
(d) at distance — from the plane base or
(e) at distance — from the plane base.
Ans: d
117. The C.G. of a plane lamina will not be at its
geometrical centre in the case of a
(a) right angled triangle
(b) equilateral triangle
(c) square
(d) circle
(e) rectangle.
Ans: a
119. The C.G. of a right circular solid cone of height
h lies at the following distance from the base
(a) h/2
(b) J/3
(c) h/6
(d) h/4
(e) 3/i/5.
Ans: d
122. The M.I. of hollow circular section about a
central axis perpendicular to section as compared
to its M.I. about horizontal axis is
(a) same
(b) double
(c) half
(d) four times
(e) one fourth.
Ans: b
126. Which of the following is the example of lever
of first order
(a) arm of man
(b) pair of scissors
(c) pair of clinical tongs
(d) all of the above
(e) none of the above.
Ans: d
127. A pair of smith's tongs is an example of the
lever of
(a) zeioth order
(b) first order
(c) second order
(d) third order
(e) fourth order.
Ans: c
128. In the lever of third order, load W, effort P and
fulcrum F are oriented as follows
(a) W between P and F
(b) F between W and P
(c) P between W and F
(d) W, P and F all on one side
(e) none of the above.
Ans: a
129. The angle which an inclined plane makes with
the horizontal when a body placed on it is about to
move down is known as angle of
(a) friction
(b) limiting friction
(c) repose
(d) kinematic friction
(e) static friction.
Ans: c
130. In actual machines
(a) mechanical advantage is greater than velocity
ratio
(b) mechanical advantage is equal to velocity ratio
(c) mechanical advantage is less than velocity ratio
(d) mechanical advantage is unity
(e) none of the above.
Ans: c
131. In ideal machines
(a) mechanical advantage is greater than velocity
ratio
(b) mechanical advantage is equal to velocity ratio
(c) mechanical advantage is less than velocity ratio
(d) mechanical advantage is unity
(e) none of the above.
Ans: b
136. A cable with a uniformly distributed load per
horizontal meter run will take the following shape
(a) straight line
(b) parabola
(c) hyperbola
(d) elliptical
(e) part of a circle.
Ans: b

Fluid Mechanics interviewquestions and answers

1. Why the Centrifugal Pump is called High Discharge pump?
Centrifugal pump is a kinetic device. The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller. The centrifugal action of the impeller accelerates the liquid to a high velocity, transferring mechanical (rotational) energy to the liquid. So it discharges the liquid in high rate. It is given in the following
formulae:
Centrifugal force F= (M*V2)/R.
Where, M-Mass;  V-Velocity; R-Radius

2. How Cavitation can be eliminated by Pump?
Cavitation means bubbles are forming in the liquid. ·
To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
To increase the pressure of the Suction Head, or  Decrease the Pump Speed.

3. Why Cavitation will occur in Centrifugal Pump and not in Displacement Pump?
The formation of cavities (or bubbles) is induced by flow separation, or non-uniform flow velocities, inside a pump casing. In centrifugal pumps the eye of the pump impeller is smaller than the flow area of pipe. This decrease in flow area of pump results in increase in flow rate. So pressure drop happened between pump suction and the vanes of the impeller. Here air bubbles or cavities are formed because of liquid vapour due to increase in temperature in impeller. This air bubbles are transmitted to pump which forms cavitation.

4. Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?

Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

5. Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?

The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.
Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change. One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

6. How Cavitation can be eliminated in a Pump?
Cavitation means bubbles are forming in the liquid.
· To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
· To increase the pressure of the Suction Head, or
· Decrease the Pump Speed.

7. Which pump is more efficient Centrifugal pump or Reciprocating pump?
Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

8. Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?
The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.  Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity  change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change. One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

9. What is a radial-flow turbine?
In a radial-flow turbine, steam flows outward from the shaft to the casing. The unit is usually a reaction unit, having both fixed and moving blades.

10. What are four types of turbine seals?
Carbon rings fitted in segments around the shaft and held together by garter or retainer springs. Labyrinth mated with shaft serration’s or shaft seal strips. Water seals where a shaft runner acts as a pump to create a ring of water around the shaft. Use only treated water to avoid shaft pitting. Stuffing box using woven or soft packing rings that are compressed with a gland to prevent leakage along the shaft.

11. What are two types of clearance in a turbine?
Radial – clearance at the tips of the rotor and casing.
Axial – the fore-and-aft clearance, at the sides of the rotor and the casing.

12. What is the function of a thrust bearing?
Thrust bearings keep the rotor in its correct axial position.

13. What is a stage in a steam turbine?  In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a "stage." A single Curtis stage may consist of two or more rows of moving blades.

14. What is a diaphragm?
Partitions between pressure stages in a turbine’s casing are called diaphragms. They hold the vane- shaped nozzles and seals between the stages. Usually labyrinth-type seals are used. One-half of the diaphragm is fitted into the top of the casing, the other half into the bottom.

15. What are the two basic types of steam turbines?
Impulse type. Reaction type.

16. What are topping and superposed turbines?Topping and superposed turbines arc high- pressure, non-condensing units that can be added to an older, moderate-pressure plant. Topping turbines receive high-pressure steam from new high-pressure boilers. The exhaust steam of the new turbine has the same pressure as the old boilers and is used to supply the old turbines.

17. What is a combination thrust and radial bearing?
This unit has the ends of the Babbitt bearing extended radically over the end of the shell. Collars on the rotor face these thrust pads, and the journal is supported in the bearing between the thrust collars.

Production Technology Objective type Questions and Answers

1. Work study is concerned with
(a) improving present method and finding
standard time
(b) motivation of workers
(c) improving production capability
(d) improving production planning and control
(e) all of the above.
Ans: a
2. Basic tool in work study is
(a) graph paper
(b) process chart
(c) planning chart
(d) stop watch
(e) analytical mind.
Ans: d
3. What does symbol 'O' imply in work study
(a) operation
(b) inspection
(c) transport
(d) delay/temporary storage
(e) none of the above.
Ans: a
4. What does symbol 'D' imply in work study
(a) inspection
(b) transport
(c) delay/temporary storage
(d) permanent storage
(e) none of the above.
Ans: c
5. What does symbol 'V' employ in work study
(a) operation
(b) inspection
(c) delay/ temporary Storage
(d) permanent storage
(e) none of the above.
Ans: d
6. Material handling in automobile industry is done
by
(a) overhead crane
(b) trolley
(c) belt conveyor
(d) all of the above
(e) none of the above.
Ans: a
7. String diagram is used when
(a) team of workers is working at a place
(b) material handling is to be done
(c) idle time is to be reduced
(d) all of the above
(e) none of the above.
Ans: a
8. Work study is most useful
(a) where production activities are involved
(b) in judging the rating of machines
(c) in improving industrial relations
(d) in judging the output of a man and improving it
(e) where men are biggest contributor to success of
a project.
Ans: a
9. Micromotion study is
(a) enlarged view of motion study
(b) analysis of one stage of motion study
(c) minute and detailed motion study
(d) subdivision of an operation into therbligs and
their analysis
(e) motion study of small components upto mirco-
seconds.
Ans: d
10. In micromotion study, therblig is described by
(a) a symbol
(b) an event
(c) an activity
(d) micro motions
(e) standard symbol and colour.
Ans: e
11. The allowed time for a job equals standard time
plus
(a) policy allowance
(b) interference allowance
(c) process allowance
(d) learning allowance
(e) unforeseen allowance.
Ans: a
12. Micromotion study involves following number of
fundamental hand motions
(a) 8
(b) 12
(c) 16
(d) 20
(e) 24
Ans: c
13. The standard time for a job is
(a) total work content
(b) base time + relaxation time
(c) total work content + basic time
(d) total work content + delay contingency
allowance
(e) total work content + relaxation time.
Ans: d
14. Work study is done with the help of
(a) process chart
(b) material handling
(c) stop watch
(d) all of the above
(e) none of the above.
Ans: c
15. Scheduling gives information about
(a) when work should start and how much work
should be completed during a certain period
(b) when work should complete
(c) that how idle time can be minimized
(d) proper utilisation of machines
(e) none of the above.
Ans: a
16. Expediting function consists in keeping a watch
on
(a) operator's activity
(b) flow of material and in case of trouble locate
source of trouble
(c) minimising the delays
(d) making efficient despatching
(e) none of the above.
Ans: b
17. Choose the wrong statement Time study is used
to
(a) determine overhead expenses
(b) provide a basis for setting piece prices or
incentive wages
(c) determine standard costs
(d) determine the capability of an operator to handle
the number of machines
(e) compare alternative methods.
Ans: a
18. Job evaluation is the method-of determining the
(a) relative worth of jobs
(b) skills required by a worker
(c) contribution of a worker
(d) contribution of a job
(e) effectiveness of various alternatives.
Ans: a
19. Micromotion study is
(a) analysis of a man-work method by using a
motion picture camera with a timing device in the
field of view
(b) motion study* observed on enhanced time
intervals
(c) motion study of a sequence of operations
conducted systematically
(d) study of man and machine conducted
simultaneously
(e) scientific, analytically procedure for
determining optimum work method.
Ans: a
20. Per cent idle time for men or machines is found
by
(a) work sampling
(b) time study
(c) method study
(d) work study
(e) ABC analysis.
Ans: a
21. TMU in method time measurement stands for
(a) time motion unit
(b) time measurement unit
(c) time movement unit
(d) technique measurement unit
(e) time method unit.
Ans: b
22. Time study is
(a) the appraisal, in terms of time, of the value of
work involving human effort
(b) machine setting time
(c) time taken by workers to do a job
(d) method of fixing time for workers
(e) method of determining the personnel
Requirement.
Ans: a
23. Work sampling observations are taken on the
basis of
(a) detailed calculations
(b) convenience
(c) table of random numbers
(d) past experience
(e) fixed percentage of daily production.
Ans: c
24. One time measurement unit (TMU) in method
time measurement system equals
(a) 0.0001 minute
(b) 0.0006 minute
(c) 0.006 minute
(d) 0.001 minute
(e) 0.06 minute.
Ans: b
25. Basic motion time study gives times for basic
motions in ten thousandths of
(a) second
(b) minute
(c) hour
(d) day
(e) none of the above.
Ans: b
26. Choose the wrong statement. Motion study is
used for
(a) improving a work method
(b) improvising a work method
(c) designing a work method
(d) providing a schematic framework
(e) reducing inventory costs.
Ans: e
27. Gnatt chart provides information about the
(a) material handling
(b) proper utilisation of manpower
(c) production schedule
(d) efficient working of machine
(e) all of the above.
Ans: c
28. ABC analysis deals with
(a) analysis of process chart
(b) flow of material
(c) ordering schedule of job
(d) controlling inventory costs money
(e) all of the above.
Ans: d
29. Process layout is employed for
(a) batch production
(b) continuous type of product
(c) effective utilisation of machines
(d) all of the above
(e) none of the above.
Ans: a
30. For a product layout the material handling
equipment must
(a) have full flexibility
(b) employ conveyor belts, trucks, tractors etc.
(c) be a general purpose type
(d) be designed as special purpose for a particular
application
(e) arranging shops according to specialization of
duties.
Ans: d
31. Travel charts provide
(a) an idea of the flow of materials at various stages
(b) a compact estimate of the handling which must
be done between various work sections
(c) the information for changes required in
rearranging material handling equipment
(d) an approximate estimate of the handling which
must be done at a particular station
(g) solution to handling techniques to achieve
most optimum^ results.
Ans: b
32. Product layout is employed for
(a) batch production
(b) continuous production
(c) effective utilization of machine
(d) all of the above
(e) none of the above.
Ans: b
33. The most important objective behind plant layout
is
(a) overall simplification, safety of integration
(b) economy in space
(c) maximum travel time in plant
(d) to provide conveniently located shops
(e) to avoid any bottlenecks.
Ans: a
34. The process layout is best suited where
(a) specialisation exists
(b) machines are arranged according to sequence of
operation
(c) few number of non-standardised units are to be
produced
(d) mass production is envisaged
(e) bought out items are more.
Ans: c
35. A low unit cost can be obtained by following
(a) product layout
(b) functional layout
(c) automatic material handling equipment
(d) specialisation of operation
(e) minimum travel time plan and com¬pact layout.
Ans: a
36. Military organisation is known as
(a) line organisation
(b) line and staff organisation
(c) functional organisation
(d) all of the above
(e) none of the above.
Ans: a
37. The main disadvantage of line organisation is
(a) top level executives have to do excessive work
(b) structure is rigid
(c) communication delays occur
(d) all of the above
(e) none of the above.
Ans: d
38. The main advantage of line organisation is its
(a) effective command and control
(b) defined responsibilities at all levels
(c) rigid discipline in the organisation
(d) ability of quick decision at all levels
(e) all of the above.
Ans: e
39. Frederick W. Taylor introduced a system of
working known as
(a) line organisation
(b) line and staff organisation
(c) functional organisation
(d) effective organisation
(e) none of the above.
Ans: c
40. The salient feature of functional organisation is
(a) strict adherence to specification
(b) separation of planning and design part
(c) each individual maintains functional efficiency
(d) work is properly planned and distributed
(e) all of the above.
Ans: e
41. The most popular type of organisation used for
Civil Engineering Constructions is
(a) line organisation
(b) line and staff organisation
(c) functional organisation
(d) effective organisation
(e) none of the above.
Ans: a
42. Templates are used for
(a) a planning layout
(b) flow of material
(c) advancing a programme in automatic machines
(d) copying complicated profiles
(e) none of the above.
Ans: a
43. In steel plant the most important system for
materials handling is
(a) conveyors
(b) cranes and hoists
(c) trucks
(d) locos
(e) none of the above.
Ans: d
44. Routing prescribes the
(a) flow of material in the plant
(b) proper utilization of man power
(c) proper utilization of machines
(d) inspection of final product
(e) none of the above.
Ans: a
45. Queuing theory deals with problems of
(a) material handling
(b) reducing the waiting time or idle Jajme
(c) better utilization of man services
(d) effective use of machines
(e) none of the above.
Ans: b
46. Standard time is defined as
(a) normal time + allowances
(b) normal time + idle time + allowances
(c) normal time + idle time
(d) only normal time for an operation
(e) none of the above.
Ans: a
47. Father of industrial engineering is
(a) Jeck Gilberth
(b) Gnatt
(c) Taylor
(d) Newton
(e) none of the above.
Ans: b
48. The grouping of activities into organisational
units is called
(a) corporate plans
(b) higher level management
(c) functional authority
(d) departmentatidn
(e) company policy.
Ans: d
49. Which of the following organisation is preferred
in automobile industry
(a) functional organisation
(b) line organisation
(c) staff organisation
(d) line and staff organisations
(e) scalar organisation.
Ans: d
50. Which of the following organisations is best
suited for steel plants
(a) functional organisation
(b) line organisation
(c) staff organisation
(d) line, staff and functional organisations
(e) scalar organisation.
Ans: d
51. The wastage of material in the store is taken
into account by the following method in the
evaluation of the material issued from the store
(a) inflated system
(b) primary cost method
(c) current value method
(d) fixed price method
(e) variable price method.
Ans: a
52. Which of the following is independent of sales
forecast
(a) productivity
(b) inventory control
(c) production planning
(d) production control
(e) capital budgeting.
Ans: a
53. Gnatt charts are used for
(a) forecasting sales
(b) production schedule
(c) scheduling and routing
(d) linear programming
(e) none of the above.
Ans: b
54. Inventory management consists of
(a) effective running of stores
(b) state of merchandise methods of stroing and
maintenance etc.
(c) stock control system
(d) all of the above
(e) none of the above.
Ans: d
55. Gnatt charts provide information about
(a) break even point analysis
(b) production schedule
(c) material handling layout
(d) determining selling price
(e) value analysis.
Ans: b
56. Inventory control in production, planning and
control aims at
(a) achieving optimisation
(b) ensuring against market fluctuations
(c) acceptable customer service at low capital
investment in inventory
(d) discounts allowed in bulk purchase
(e) regulate supply and demand.
Ans: c
57. In inventory control, the economic order quantity
is the
(a) optimum lot size
(b) highest level of inventory
(c) lot corresponding to break-even point
(d) capability of a plant to produce
(e) none of the above.
Ans: a
58. Statistical quality control techniques are based
on the theory of
(a) quality
(b) statistics
(c) probability
(d) all of the above
(e) none of the above.
Ans: c
59. The appellate authority for an industrial dispute
is
(a) management
(b) labour court
(c) high court/supreme court
(d) board of directors
(e) president.
Ans: c
60. Under the Apprenticeship Act
(a) all industries have to necessarily train the
apprentices
(b) industries have to train apprentices ac-cording
to their requirement
(c) all industries employing more than 100 workers
have to recruit apprentices
(d) only industries employing more than 500
workers have to recruit apprentices
(e) all industries other than small scale industries
have to train apprentices.
Ans: d
61. Standing orders which are statutory are
applicable to
(a) all industries
(b) all process industries and thermal power plants
(c) only major industries
(d) only key industries
(e) all industries employing more than 100 workers.
Ans: e
62. Acceptance sampling is widely used in
(a) batch production
(b) job production
(c) mass production
(d) all of the above
(e) none of the above.
Ans: c
63. The technique of value analysis can be applied
to
(a) complicated items only
(b) simple items only
(c) crash programmer items only
(d) cost consciousness items only
(e) any item.
Ans: e
64. The term 'value' in value engineering refers to
(a) total cost of the product
(b) selling price of the product
(c) utility of the product
(d) manufactured cost of the product
(e) depreciation value.
Ans: c
65. Value engineering aims at finding out the
(a) depreciation value of a product
(b) resale value of a product
(c) major function of the item and accomplishing the
same at least cost without change in quality
(d) break even point when machine re-quires
change
(e) selling price of an item.
Ans: c
66. In the perpetual inventory control, the material
is checked when it reaches its
(a) minimum value
(b) maximum value
(c) average value
(d) alarming value
(e) original value.
Ans: a
67. According to MAPI formula, the old machine
should be replaced by new one when
(a) CAM < DAM
(b) CAM > DAM
(c) CAM = DAM
(d) there is no such criterion
(e) none of the above.
(CAM = Challenger's Adverse minimum DAM =
Defender's Adverse minimum)
Ans: a
68. Merit Rating is the method of determining worth
of
(a) a job
(b) an individual employee
(c) a particular division in workshop
(d) machine
(e) overall quality.
Ans: b
69. Material handling and plant location is analysed
by
(a) Gnatt chart
(b) bin chart
(c) Emerson chart
(d) travel chart
(e) activity chart.
Ans: d
70. Works cost implies
(a) primary cost
(b) factory cost
(c) factory expenses
(d) primary cost + factory expenses
(e) none of the above.
Ans: d
71. Motion study involves analysis of
(a) actions of operator
(b) layout of work place
(c) tooling and equipment
(d) all of the above
(e) none of the above.
Ans: a
72. Standard time as compared to normal time is
(a) greater
(b) smaller
(c) equal
(d) there is no such correlation
(e) none of the above.
Ans: a
73. Pick up the incorrect statement about
advantages of work sampling
(a) permits a fine breakdown of activities and
delays
(b) simultaneous study of many operators may be
made by a single observer
(c) calculations are easier, method is economical
and less time consuming
(d) no time measuring devices are generally
needed
(e) as operators are not watched for long periods,
chances of obtaining misleading results are less.
Ans: a
74. In which of the following layouts, the lines need
to the balanced
(a) process layout
(b) product layout
(c) fixed position layout
(d) plant layout
(e) functional layout.
Ans: b
75. Which of the following layouts is suited for mass
production
(a) process layout
(b) product layout
(c) fixed position layout
(d) plant layout
(e) functional layout.
Ans: b
76. Which of the following layouts is suited to job
production
(a) process layout
(b) product layout
(c) fixed position layout
(d) plant layout
(e) functional layout.
Ans: a
77. The employees provident fund act is applicable
to
(a) all industries
(b) all industries other than small and medium
industries
(c) volunteers
(d) the industries notified by Government
(e) all major industries.
Ans: d
78. The amount deducted from the salary of
workers towards employees provident fund is
(a) credited into reserves of company
(b) deposited in nationalised bank
(c) deposited in post office
(d) deposited in the account of worker with
employer or Reserve Bank of India
(e) deposited in the account of worker with
Provident Fund Commissioner.
Ans: e
79. The deductions for, employees provident fund
start
(a) immediately on joining the service
(b) after 60 days of joining the service
(c) after 100 days of joining the service
(d) after 240 days of joining the service
(e) after one year of joining the service.
Ans: d
80. Father of time study was
(a) F.W. Taylor
(b) H.L. Gantt
(c) F.B. Gilberfh
(d) R.M. Barnes
(e) H.B. Maynord.
Ans: a
81. Tick the odd man out
(a) Taylor
(b) Drucker
(c) McGregor
(d) Galileo
(e) Parkinson.
Ans: d
82. Current assets include
(a) manufacturing plant
(b) manufacturing plant and equipment
(c) inventories
(d) common stock held by the firm
(e) all of the above.
Ans: a
83. The objective of time study is to determine the
time required to complete a job by
(a) fast worker
(b) average worker
(c) slow worker
(d) new entrant
(e) any one of the above.
Ans: b
84. Job enrichment technique is applied to
(a) reduce labour monotony
(b) overcome boring and demotivating work
(c) make people happy
(d) all of the above
(e) none of the above.
Ans: d
85. For ship vessel industry the following layout is
best suited
(a) process layout
(b) product layout
(c) fixed position layout
(d) plant layout
(e) functional layout.
Ans: c
86. In Halsey 50-50 plan, output standards are
established
(a) by time study
(b) from previous production records
(c) from one's judgement
(d) all of the above
(e) none of the above.
Ans: b
87. Routing is essential in the following type of
industry
(a) assembly industry
(b) process industry
(c) job order industry
(d) mass production industry
(e) steel industry.
Ans: a
88. An optimum project schedule implies
(a) optimum utilization of men, machines and
materials
(b) lowest possible cost and shortest possible time
for project
(c) timely execution of project
(d) to produce best results under given constraints
(e) realistic execution time, minimum cost and
maximum profits.
Ans: b
89. Graphical method, simplex method, and
transportation method are concerned with
(a) break-even analysis
(b) value analysis
(c) linear programming
(d) queing theory
(e) tnaterial handling.
Ans: c
90. Which one of the following represents a group
incentive plan ?
(a) Scanlon Plan
(b) Rowan Plan
(c) Bedaux Plan
(d) Taylor Differential Piece Rate System
(e) Halsey Premium Plan.
Ans: a
91. In the Halsey 50-50 plan, the following are
rewarded more
(a) past good workers
(b) past poor workers
(c) past average workers
(d) all of the above
(e) none of the above.
Ans: b
92. In the Halsey system of wage incentive plan, a
worker is
(a) paid as per efficiency
(b) ensured of minimum wages
(c) not paid any bonus till his efficiency
(d) never a loser
(e) induced to do more work.
Ans: b
93. 'Value' for value engineering and analysis
purposes is defined as
(a) purchase value
(b) saleable value
(c) depreciated value
(d) present worth
(e) function/cost.
Ans: e
94. Break-even analysis can be used for
(a) short run analysis
(b) long run analysis
(c) average of above two run analysis
(d) there is no such criterion
(e) none of the above.
Ans: a
95. CPM has following time estimate
(a) one time estimate
(b) two time estimate
(c) three time estimate
(d) four time estimate
(e) nil time estimate.
Ans: a
96. PERT has following time estimate
(a) one time estimate
(b) two time estimate
(c) three time estimate
(d) four time estimate
(e) nil time estimate.
Ans: c
97. In Lincoln plan (one type of group incentive plan)
, the amount of the profit which an .employee
receives in addition to the guaranteed basic pay/
wages, is based on :
(a) a standard rating system
(b) a merit rating system
(c) a job evaluation system
(d) his individual performance
(e) all of the above.
Ans: b
98. Which of the following incentive plansrensures a
part of the swing to the worker and rest to the
employer
(a) Emerson efficiency plan
(b) Taylor plan
(c) Halsey premium plan
(e) Gilberth plan.
Ans: c
99. Which of the following is not wage incentive plan
(a) differential piece rate system
(b) Rowan plan
(c) Emerson plan
(d) Taylor plan
(e) Halsey plan.
Ans: d
100. Which of the following plans motivates
supervisors by paying a premium on time saved by
workers
(a) Halsey plan
(b) Rowan plan
(c) Haynes plan
(d) Emerson's plan
(e) Taylor's plan.
Ans: c
101. The time required to complete a task is
established and a bonus is paid to the worker for
every hour he saves from the established time
required. This type of incentive plan is known as
(a) Rowan Plan
(b) Bedaux Plan
(c) Taylor Differential Piece rate system
(d) Halsey Premium plan
(e) Day work plan.
Ans: d
102. One of the basic essentials of an incentive plan
is that
(a) a differential piece rate system should exist
(b) minimum wages should be guaranteed
(c) provide incentive to group efficiency
performance
(d) all standards should be based on optimum
standards of production
(e) all standards should be based on time studies.
Ans: e
103. In the Emerson efficiency plan, a worker
receives only his daily wage and no bonus is paid
till his efficiency reaches
(a) 50%
(b) 661%
(c) 75%
(d) 80%
(e) 90%.
Ans: b
104. According to Rowan plan, if H = hourly rate, A =
actual time and S = standard time, then wages will
be
(a) HA
(b) HA + (S~A) HA
(c) HA + ^^-H
(d) HA + ^^-H
(e) HA + ^^-HA.
Ans: b
105. If a worker gets a daily wage of Rs HA, then
according to Rowan plan, his maximum daily
earnings can be
(a) 2 HA
(b) 1.33 HA
(c) 1.5 HA
(d) 1.15 HA
(e) 2.5 HA.
Ans: a
106. In A-B-C control policy, maximum attention is
given to
(a) those items which consume money
(b) those items which are not readily available
(c) those x items which are in more demand
(d) those items which consume more money
(e) proper quality assurance program-mes.
Ans: d
107. Which one of the following represents a group
incentive plan ?
(a) Halsey Premium Plan
(b) Bedaux Plan
(c) Lincoln Plan
(d) Rowan Plan
(e) Taylor Plan.
Ans: c
108. The mathematical technique for finding the best
use of limited resources in an optimum manner is
known as
(a) operation research
(b) linear programming
(c) network analysis
(d) queuing theory
(e) break-even analysis.
Ans: b
109. In order that linear programming techniques
provide valid results
(a) relations between factors must be linear
(positive)
(b) relations between factors must be linear
(negative)
(c) (a) or (b)
(d) only one factor should change at a time, others
remaining constant
(e) none of the above.
Ans: c
110. The linear programming techniques can be
applied successfully to industries like
(a) iron and steel
(b) food processing
(c) oil and chemical
(d) banking
(e) all of the above.
Ans: e
111. The simplex method is the basic method for
(a) value analysis
(b) operation research
(c) linear programming
(d) model analysis
(e) none of the above.
Ans: c
112. The two-bin system is concerned with
(a) ordering procedure
(b) forecasting sales
(c) production planning
(d) despatching and expediting
(e) none of the above.
Ans: a
113. The time required to complete a job is
established and a bonus is paid to the worker based
on the exact % of time
saved. This type of incentive plan is known as
(a) Dry work Plan
(b) Halsey Premium Plan
(c) Taylor Plan
(d) Bedaux Plan
(e) Rowan Plan.
Ans: e
114. Replacement studies are made on the fol-
lowing basis:
(a) annual cost method
(b) rate of return method
(c) total life average method
(d) present worth method
(e) any one of the above.
Ans: e
115. String diagram is used
(a) for checking the relative values of various
layouts
(b) when a group of workers are working at a place
(c) where processes require the operator to be
moved from one place to another
(d) all of the above
(e) none of the above.
Ans: d
116. Which of the following depreciation system
ensures that the interest be charged on the cost of
machine asset every year on the book value, but
the rate of depreciation every year remains
constant
(a) sinking fund method
(b) straight line method
(c) A-B-C charging method
(d) annuity charging method
(e) diminishing balance method.
Ans: d
117. Bin card is used in
(a) administrative wing
(b) workshop
(c) foundry shop
(d) stores
(e) assembly shop.
Ans: d
118. Slack represents the difference between the
(a) latest allowable time and the normal expected
time
(b) latest allowable time and the earliest expected
time
(c) proposed allowable time and the earliest
expected time
(d) normal allowable time and the latest expected
time
(e) project initiation tune and actual starting time.
Ans: b
119. PERT and CPM are
(a) techniques to determine project status
(b) decision making techniques
(c) charts which increase aesthetic appearance of
rooms
(d) aids to determine cost implications of project
(e) aids to the decision maker.
Ans: e
120. A big advantage of PERT over Gantt charts is
that in the former case
(a) activities and events are clearly shown
(b) early start and late finish of an activity are
clearly marked
(c) activity times are clear
(d) critical path can be easily determined
(e) inter-relationship among activities is clearly
shown.
Ans: e
121. CPM is the
(a) time oriented technique
(b) event oriented technique
(c) activity oriented technique
(d) target oriented technique
(e) work oriented technique.
Ans: c
122. PMTP (predetermined motion time systems)
include
(a) MTM (method time measurement)
(b) WFS (work factor systems)
(c) BNTS (basic motion time study)
(d) all of the above
(e) none of the above
Ans: d
123. Work study comprises following main
techniques
(a) method study and work measurement
(b) method study and time study
(c) time study and work measurement
(d) method study and job evaluation
(e) value analysis and work measurement.
Ans: a
124. Which of the following equations is not in
conformity with others
(a) organisation performance x motivation = profits
(b) knowledge x skill = ability
(c) ability x motivation = performance
(d) attitude x situation = motivation
(e) performance x resources
Ans: a
125. PERT is the
(a) time oriented technique
(b) event oriented technique
(c) activity oriented technique
(d) target oriented technique
(e) work oriented technique.
Ans: b
126. The basic difference between PERT and CPM
is that
(a) PERT deals with events and CPM with activities
(b) critical path is determined in PERT only
(c) costs are considered on CPM only and not in
PERT
(d) guessed times are used in PERT and evaluated
times in CPM
(e) PERT is used in workshops and CPM in plants.
Ans: d
127. PERT stands for k (fit) project evaluation and
review technique
(b) project examination and review technique
(c) project evaluation and reporting technique
(d) process execution and reporting technology
(e) project execution and results technique.
Ans: a
128. Queuing theory is used for
(a) inventory problems
(b) traffic congestion studies
(c) job-shop scheduling
(d) all of the above
(e) none of the above.
Ans: d
129. In queuing theory, the nature of the waiting
situation can be studied and analysed
mathematically if
(a) complete details'of items in, waiting line are
known
(b) arrival and waiting times are known and can be
grouped to form a waiting line model
(c) all variables and constants are known and form
a linear equation
(d) the laws governing arrivals, service times, and
the order in which the arriving units are taken into
source are known
(e) all of the above.
Ans: d
130. Queuing theory is associated with
(a) sales
(b) inspection time
(c) waiting time
(d) production time
(e) inventory.
Ans: c
131. The reasons which are basically responsible
for the formation of a queue should be that
(a) the average service rate Hess than the average
arrival rate
(b) output rate is linearly proportional to input
(c) output rate is constant and the input varies in a
random manner
(d) all of the above
(e) none of the above.
Ans: d
132. Monte Carlo solutions in queuing theory are
extremely useful in queuing problems
(a) that can't be analysed mathematically
(b) involving multistage queuing
(c) to verify mathematical results
(d) all of the above
(e) none of the above.
Ans: a
133. In perpetual inventory control, the material is
checked as it reaches its
(a) minimum value
(b) maximum value
(c) average value
(d) middle value
(e) alarming value.
Ans: a
134. A milestone chart
(a) shows the inter dependences of various jobs
(b) depicts the delay of jobs, if any
(c) points outgoing ahead of schedule of jobs, if any
(d) all of the above
(e) none of the above.
Ans: e
135. Bar charts are suitable for
(a) minor works
(b) major works
(c) large projects
(d) all of the above
(e) none of the above.
Ans: a
136. The first method invented for planning projects
was
(a) bar chart method
(b) milestone chart
(c) critical path method (CPM)
(d) programme evaluation and review technique
(PERT)
(e) none of the above.
Ans: a
137. Pick up the correct statement from the
following
(a) programmer evaluation and review technique is
event oriented
(b) programmer evaluation and review technique is
not event oriented
(c) critical path method is event oriented
(d) critical.path method is not activity oriented
(e) none of the above.
Ans: e
138. Pick up the correct statement from the
following
(a) critical path method is an improvement upon bar
chart method
(b) critical path method provides a realistic
approach to the daily problems
(c) critical path method avoids delays which are
very common in bar chart
(d) critical path method was invented by Morgan R.
Walker of Dupot and James E. Kelley of Remington
U.S.A in 1957
(e) all of the above.
Ans: e
139. Pick up the correct step used for scheduling a
project by C.P.M.
(a) a project is divided into various activities
(b) required time for each activity is established
(c) sequence of various activities is made
according to their importance
(d) network is drawn by connecting the activities
and the events
(e) all of the above.
Ans: e
140. The time of completing a project in network
analysis is given by following time of the critical
activity meeting at the finalitiode
(a) early finish
(b) early start
(c) late start
(d) late finish
(e) none of the above.
Ans: a
141. The disadvantage of product layout is
(a) high initial investment for the specialized
facilities
(b) skilled labour to operate machines
(c) production time is longer, requiring more goods
in inventory
(d) high cost of inspection
(e) costly and complex production control.
Ans: a
142. Emergency rush order can be pushed more
effectively in
(a) job production
(b) automatic production
(c) continuous production
(d) intermittent production
(e) none of the above.
Ans: d
143. Routing assists engineers in deciding in
advance
(a) the flow of material in the plant
(b) the methods of proper utilization of manpower
(c) the methods of proper utilization of machines
(d) the layout of factory facilities
(e) normal route of workers through the plant.
Ans: c
144. The performance of a specific task in CPM is
known as
(a) dummy
(b) event
(c) activity
(d) contract
(e) none of the above.
Ans: c
145. Pick up the incorrect statement from the
following
(a) an activity of the project is denoted by an arrow
on the net work
(b) the tail of the arrow indicates the start of the
activity
(c) the head of the arrow indicates the end of,the
activity!
(d) the arrows are drawn (to scale from) left to right
(e) each activity consumes a given time
Ans: d
146. The artificial activity; which indicates that an
activity following it cannot be started unless, the
preceding activity is complete, is known as
(a) event
(b) free float
(c) artificial
(d) constraint
(e) dummy.
Ans: e
147. A dummy activity
(a) is artificially introduced
(b) is represented by a dotted line
(c) does not require any time
(d) all of the above
(e) none of the above.
Ans: d
148. If E is the duration, ES and EF are die earliest
start and finish times, LS and LF are latest start
and finish times, then the following relation holds
good
(a) EF=ES+D
(b) LS=LF-D
(c) LF = LS + D
(d) D = EF-ES
(e) all of the above.
Ans: e
149. The difference between the time available to do
the job and the time required to do the job, is known
as
(a) event
(b) float
(c) duration
(d) constraint
(e) none of the above.
Ans: b
150. The probability distribution of activity times in
PERT follows following distribution
(a) normal
(b) binomial
(c) beta
(d) exponential
(e) Gaussian.
Ans: c
151. The probability distribution of project
completion in PERT follows following distribution
(a) normal
(b) binomial
(c) beta
(d) exponential
(e) Gaussian.
Ans: e
152. If TL is the largest allowable event occurrence
time, total activity slack (s) is equal to
(a) latest start time - earliest start time
(b) latest finish time - earliest finish time (EFT)
(c) TL-EFT
(d) all of the above
(e) none of the above.
Ans: d
153. The critical activity has
(a) maximum float
(p) minimum float
(c) zero float,
(d) average float
(e) none of these.
Ans: c
154. The time by which the activity completion time
can be delayed without affecting the start of
succeeding activities, is Known as
(a) duration
(b) total float
(c) free float
(d) interfering float
(e) none of the above.
Ans: c
155. The critical path of a network represents
(a) the minimum time required for completion of
project
(b) the maximum time required for completion of
project
(c) maximum cost required for completion of project
(d) minimum cost required for completion of project
(e) none of the above.
Ans: a
156. Pick up the correct statement from the
following
(a) the float may be positive, zero or negative
(b) if the float is positive and the activity is delayed
by a period equal to its total float, the completion of
project in not delayed
(c) if the float of an activity is negative, delay in its
performance is bound to delay the completion of
project
(d) if the float of an activity is zero, the activity is
critical and any delay in its performance will delay
the whole project
(e) all of the above.
Ans: e
157. Critical path moves along the activities having
total float of
(a) positive value
(b) negative value
(c) zero value
(d) same value
(e) none of the above.
Ans: c
158. Critical Path Net Work helps an engineer
(a) to concentrate his attention on critical activities
(b) to divert the resources from non-critical
advanced activities to critical activities
(c) to be cautious for avoiding any delay in the
critical activities to avoid delay of the whole project
(d) all of the above
(e) none of the above.
Ans: d
159. Pick up the correct statement about
relationship between various floats
(a) free float = total float
(b) independent float = total float
(c) independent float > free float
(d) free float > total float
(e) independent float < free float.
Ans: e
160. The time which results in the least possible
direct cost of an activity is known as
(a) normal time
(b) slow time
(c) crash time
(d) standard time
(e) none of the above.
Ans: b
161. The technique for establishing and maintaining
priorities among the various jobs of any project is
known as
(a) event flow scheduling technique
(b) critical ratio scheduling
(c) slotting technique for scheduling
(d) short interval scheduling
(e) none of the above.
Ans: b
162. Pick up the incorrect statement from the
following. A critical ratio scheduling
(a) establishes the relative priorities among various
activities on a common basis
(b) determines the status of each activity
(c) adjusts automatically changes in activity
progress
(d) is a dynamic system
(e) none of the above.
Ans: e
163. PERT is
(a) an analytic tool in concept
(b) limit up of event oriented diagrams
(c) used for research and development projects
(d) based on three time estimates for activities
linking up two events
(e) all of the above.
Ans: e
164. CPMis
(a) synthesising in concepts
(b) is built of activities oriented program-mes
(c) is, based on one time eytimate
(d) is used for repetitive works
(e) all of the above.
Ans: e
165. A CPM family includes
(a) CPA (Critical Path Analysis)
(b) CPP (Critical Path Plotted)
(c) MCE (Minimum Cost Expenditure)
(d) CPS (Critical Path Scheduling)
(e) all of the above.
Ans: e
166. PERT/CPM, techniques can be used for
following applications
(a) once through project
(b) maintenance jobs
(c) research and development
(d) all non-technical jobs
(e) all of the above.
Ans: e
167. PERT analysis is based on
(a) optimistic time
(b) pessimistic time
(c) most likely time
(d) all of the above
(e) none of the above.
Ans: d
168. Descripancies of bar chart techniques are
(a) consequential effects of lack in one activity on
omer
(b) consequential effects of lack in one activity on
the finish date
(c) free time available for an activity can't be
predicted
(d) effective monitoring/controlling can't be done
(e) all of the above.
Ans: e
169. O on a PERT/CPM chart represents
(a) an ordinary event
(b) a significant event representing some mile-
stone
(c) an event to be transferred to other network
chart
(d) dangling event
(e) dummy event.
Ans: a
170. Pick up the correct statement. Dummy activity
on a PERT/CPM chart means, it
(a) consumes time, but no resources
(b) consumes resources but no time
(c) consumes neither time nor resources
(d) is a dangling event
(e) consumes both resources and time.
Ans: c
171. Criticalpath on PERT/CPM chart is obtained by
joining the events having
(a) maximum slack
(b) minimum slack
(c) average slack
(d) no slack
(e) judgement and experience.
Ans: b
172. Slack of various events on the critical path in
PERT/CPM chart
(a) increases continuously
(b) decreases continuously
(c) remains constant
(d) may increase or decrease depending on various
factors
(e) unpredictable.
Ans: c
173. The assumption in PERT is
(a) a project will always be behind schedule, if left
uncorrected
(b) cost of project will always be more than the
estimated cost, if no timely corrections are taken
(c) a project can be subdivided into a set of
predictable, independent activities
(d) activities are fixed and can't be changed ,
(e) commissioning time can be changed, if activities
are behind schedule.
Ans: c
174. Activity s,lack or float of any event on a PERT/
CPM chart is represented by
(a) latest start time of succeeding event -earliest
finish time of preceding event activity time
(b) latest start time of the event - earliest start time
of the event
(c) latest finish time of event - earliest finish time of
the event
(d) anyone of the above
(e) none of the above.
Ans: d
175. The important file in making a PERT is
(a) an event can't be accomplished until activities
leading to it are completed
(b) no activity from any event can be started from
preceding event till it is completed
(c) length of arrow has nothing to do with time
(d) every activity must be completed before end
point is reached
(e) all of the above.
Ans: e
176. An event is indicated on the network by
(a) a straight line
(b) a number enclosed in a circle or a square
(c) a straight line with circles at the ends
(d) a dotted line
(e) an arrow.
Ans: b
177. In a PERT chart
(a) all activities should be numbered
(b) only important activities should be numbered
(c) only critical activities are numbered
(d) only selected activities are numbered
(e) no activity is numbered.
Ans: a
178. Positive slack on a PERT indicates that project
is
(a) ahead of schedule
(b) beyond schedule
(c) as per schedule
(d) on critical path
(e) none of the above.
Ans: a
179. Pessimistic time is
(a) the maximum time which an activity might
require
(b) the average time required for a job
(c) the most probable time considering all conditions
(d) the minimum time in which an activity can
possibly be accomplished
(e) the earliest finish.
Ans: a
180. In PERT analysis, critical path is obtained by
joining events having
(a) +ve slack
(b) -ve slack
(c) zero sldck
(d) dummy activities
(e) critical activities.
Ans: c

Heat Transfer - Mechanical Engineering Multiple Choice Questions and Answers List Latest Heat Transfer Questions and Answers pdf free download

Heat Transfer -
Mechanical Engineering Multiple
Choice Questions and Answers
List

1. Unit of thermal conductivity in M.K.S. units is
(a) kcal/kg m2 °C
(b) kcal-m/hr m2 °C
(c) kcal/hr m2 °C
(d) kcal-m/hr °C
(e) kcal-m/m2 °C.
Ans: b
2. Unit of thermal conductivity in S.I. units is
(a) J/m2 sec
(b) J/m °K sec
(c) W/m °K
(d) (a) and (c) above
(e) (b) and (c) above.
Ans: e
3. Thermal conductivity of solid metals with rise
in temperature normally
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease depending on
temperature
(e) unpredictable.
Ans: b
4. Thermal conductivity of non-metallic amorphous
solids with decrease in temperature
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease depending on
temperature
(e) unpredictable.
Ans: b
5. Heat transfer takes place as per -
(a) zeroth law of thermodynamics
(b) first law of thermodynamic
(c) second law of the thermodynamics
(d) Kirchoff's law (e) Stefan's law.
Ans: c
6. When heat is transferred from one particle of hot
body to another by actual motion of the heated
particles, it is referred to as heat transfer by
(a) conduction
(b) convection
(c) radiation
(d) conduction and convection
(e) convection and radiation.
Ans: a
7. When heat is transferred form hot body to cold
body, in a straight line, without affecting the
intervening medium, it is referred as heat transfer
by
(a) conduction
(b) convection
(c) radiation
(d) conduction and convection
(e) convection and radiation.
Ans: c
8. Sensible heat is the heat required to
(a) change vapour into liquid
(b) change liquid into vapour
(c) increase the temperature of a liquid of vapour
(d) convert water into steam and superheat it
(e) convert saturated steam into dry steam.
Ans: c
9. The insulation ability of an insulator with the
presence of moisture would
(a) increase
(b) decrease
(c) remain unaffected
(d) may increase/decrease depending  on
temperature and thickness of insulation
(e) none of the above.
Ans: b
10. When heat is Transferred by molecular collision,
it is referred to as heat transfer by
(a) conduction
(b) convection
(c) radiation
(d) scattering
(e) convection and radiation.
Ans: b
11. Heat transfer in liquid and gases takes place by
(a) conduction
(b) convection
(c) radiation
(d) conduction and convection
(e) convection and radiation.
Ans: b
12. Which of the following is the case of heat
transfer by radiation
(a) blast furnace
(b) heating of building
(c) cooling of parts in furnace
(d) heat received by a person from fireplace
(e) all of the above.
Ans: d
13. Heat is closely related with
(a) liquids
(b) energy
(c) temperature
(d) entropy
(e) enthalpy.
Ans: c
14. Pick up the wrong case. Heat flowing from one
side to other depends directly on
(a) face area
(b) time
(c) thickness
(d) temperature difference
(e) thermal conductivity.
Ans: c
15. Metals are good conductors of heat because
(a) their atoms collide frequently
(b) their atoms-are relatively far apart
(c) they contain free electrons
(d) they have high density
(e) all of the above.
Ans: a
16.  Which of the following is a case of steady state
heat transfer
(a) I.C. engine
(b) air preheaters
(c) heating of building in winter
(d) all of the above
(e) none of the above.
Ans: e
17. Total heat is the heat required to
(a) change vapour into liquid
(b) change liquid into vapour
(c) increase the temperature of a liquid or vapour
(d) convert water into steam and superheat it
(e) convert saturated steam into dry steam.
Ans: d
18. Cork is a good insulator because it has
(a) free electrons
(b) atoms colliding frequency
(c) low density
(d) porous body
(e) all of the above.
Ans: d
19. Thermal conductivity of water in general with
rise in temperature
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease depending on
temperature
(e) none of the above.
Ans: d
20. Thermal conductivity of water at 20°C is of the
order of
(a) 0.1
(b) 0.23
(c) 0.42
(d) 0.51
(e) 0.64.
Ans: d
21. Temperature of steam at around 540°C can be
measured by
(a) thermometer
(b) radiatiouv pyrometer
(c) thermistor
(d) thermocouple
(e) thermopile.
Ans: d
22. Thermal conductivity of air at room temperature
in kcal/m hr °C is of the order of
(a) 0.002
(b) 0.02
(c) 0.01
(d) 0.1
(e) 0.5.
Ans: b
23. The time constant of a thermocouple is
(a) the time taken to attain the final
temperature to be measured
(b) the time taken to attain 50% of the value of initial
temperature difference
(c) the time taken to attain 63.2% of the value of
initial temperature difference
(d) determined by the time taken to reach 100°C
from 0°C
(e) none of the above.
Ans: c
24. Thermal conductivity of air with rise in
temperature
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease depending on
temperature
(e) none of the above.
Ans: a
25. Heat flows from one body to other when they
have
(a) different heat contents
(b) different specific heat
(c) different atomic structure
(d) different temperatures
(e) none of the above.
Ans: d
26. The concept of overall coefficient of heat
transfer is used in heat transfer problems of
(a) conduction
(b) convection
(c) radiation
(d) all the three combined
(e) conduction and comte_ction.
Ans: e
27. In heat transfer, conductance equals
conductivity (kcal/hr/sqm/°C/cm) divided by
(a) hr (time)
(b) sqm (area)
(c) °C (temperature)
(d) cm (thickness)
(e) kcal (heat).
Ans: d
28. The amount of heat flow through a body by
conduction is
(a) directly proportional to the surface area of the
body
(b) directly proportional to the temperature
difference on the two faces of the body
(c) dependent upon the material of the body
(d) inversely proportional to the thickness of the
body
(e) all of the above.
Ans: e
29. Which of the following has least value of
conductivity
(a) glass
(b) water
(c) plastic
(d) rubber
(e) air.
Ans: e
30.  Which of the following is expected to have
highest thermal conductivity
(a) steam
(b) solid ice
(c) melting ice
(d) water
(e) boiling water.
Ans: b
6-31. Thermal conductivity of glass-wool varies
from sample to sample because of variation in
(a) composition
(b) density
(c) porosity
(d) structure
(e) all of the above.
Ans: e
32. Thermal conductivity of a material may be
defined as the
(a) quantity of heat flowing in one second through
one cm cube of material when opposite faces ^re
maintained at a temperature difference of 1°C
(b) quantity of heat flowing in one second through a
slab of the material of area one cm square,
thickness 1 cm when its faces differ in temperature
by 1°C
(c) heat conducted in unit time across unit area
through unit thickness when a temperature
difference of unity is maintained between opposite
faces
(d) all of the above
(e) none of the above.
Ans: d
33. Which of the following has maximum value of
thermal conductivity
(a) aluminium
(b) steel
(c) brass
(d) copper
(e) lead.
Ans: a
34. Moisture would find its way into insulation by
vapour pressure unless it is prevented by
(a) high thickness of insulation
(b) high vapour pressure
(c) less thermal conductivity insulator
(d) a vapour seal
(e) all of the above.
Ans: d
35. Heat is transferred by all three modes of
transfer, viz, conduction, convection and radiation
in
(a) electric heater
(b) steam condenser
(c) melting of ice
(d) refrigerator condenser coils
(e) boiler.
Ans: e
36. According to Prevost theory of heat exchange
(a) it is impossible to transfer heat from low
temperature source to t high temperature source
(b) heat transfer by radiation requires no medium
(c) all bodies above absolute zero emit radiation
(d) heat transfer in most of the cases takes place
by combination of conduction, convection and
radiation
(e) rate of heat transfer depends on thermal
conductivity and temperature difference.
Ans: c
37. The ratio of heat flow Q1/Q2 from two walls of
same thickness having their thermal conductivities
as ATj - 2K2 will be
(a) I
(b) 0.5
(c) 2
(d) 0.25
(e) 4.0
Ans: c
38. Heat transfer by radiation mainly depends upon
(a) its temperature
(b) nature of the body
(c) kind and extent of its surface
(d) all of the above
(e) none of the above.
Ans: d
39. Thermal diffusivity is
(a) a dimensionless parameter
(b) function of temperature
(c) used as mathematical model
(d) a physical property of the material
(e) useful in case of heat transfer by radiation.
Ans: d
40. Thermal diffusivity of a substance is .
(a) proportional of thermal  conductivity
(b) inversely proportional to k
(c) proportional to (k)
(d) inversely proportional to k2
(e) none of the above.
Ans: a
41. Unit of thermal diffusivity is
(a) m2/hr
(b) m2/hr°C
(c) kcal/m2 hr
(d) kcal/m.hr°C
(e) kcal/m2 hr°C.
Ans: a
43. Thermal conductivity of wood depends on
(a) moisture
(b) density
(c) temperature
(d) all of the above
(e) none of the above.
Ans: d
44. In convection heat transfer from hot flue gases
to water tube, even though flow may be turbulent, a
laminar flow region (boundary layer of film) exists
close to the tube. The heat transfer through this film
takes place by
(a) convection
(b) radiation
(c) conduction
(d) both convection and conduction
(e) none of the above.
Ans: c
45. Film coefficient is defined as Inside diameter of
tube
(a) Equivalent thickness of film
(b) Thermal conductivity Equivalent thickness of film
Specific heat x Viscocity
(c) Thermal conductivity Molecular diffusivity of
momentum Thermal diffusivity
(d) Film coefficient x Inside diameter
Thermalconductivity
(e) none of the above.
Ans: b
46. Heat conducted througfi unit area and unit thick
face per unit time when temperature difference
between opposite faces is unity,is called
(a) thermal resistance
(b) thermal coefficient
(c) temperature gradient
(d) thermal conductivity
(e) heat-transfer.
Ans: d
49. The rate of energy emission from unit surface
area through unit solid angle, along a normal to the
surface, is known as
(a) emissivity
(b) transmissivity
(c) reflectivity
(d) intensity of radiation
(e) absorptivity.
Ans: d
50. Emissivity of a white polished body in
comparison to a black body is
(a) higher
(b) lower
(c) same
(d) depends upon the shape of body
(e) none of the above.
Ans: b
51. A grey body is one whose absorptivity
(a) varies with temperature
(b) varies with wavelength of the incident ray
(c) is equal to its emissivity
(d) does not vary with temperature and. wavelength
of the incident ray
(e) none of the above.
Ans: c
53. Two balls of same material and finish have their
diameters in the ratio of 2 : 1 and both are heated to
same temperature and allowed to cool by radiation.
Rate of cooling by big ball as compared to smaller
one will be in the ratio of
(a)  1 :1
(b)  2: 1
(c)  1 : 2
(d)  4 : 1
(e)  1 : 4.
Ans: c
55. A non-dimensional number generally associated
with natural convection heat transfer is
(a) Grashoff number
(b) Nusselt number
(c) Weber number
(d) Prandtl number
(e) Reynold number.
Ans: a
56. LMTD in case of counter flow heat exchanger as
compared-to parallel flow heat exchanger is
(a) higher
(b) lower
(c) same
(d) depends on the area of heat exchanger
(e) depends on temperature conditions.
Ans: a
57. In heat exchangers, degree of approach is
defined as the difference between temperatures of
(a) cold water inlet and outlet
(b) hot medium inlet and outlet
(c) hot medium outlet and cold water inlet
(d) hot medium outlet and cold water outlet
(e) none of the above.
Ans: d
58. In counter flow heat exchangers
(a) both the fluids at inlet (of heat ex¬changer where
hot fluid enters) are in their coldest state
(b) both the fluids at inlet are in their hot¬test state
(c) both the fluids .at exit are in their hottest state
(d) one fluid is in hottest state and other in coldest
state at inlet
(e) any combination is possible depending on design
of heat exchanger.
Ans: b
59. A steam pipe is to be insulated by two insulating
materials put over each other. For best results
(a) better insulation should be put over pipe and
better one over it
(b) inferior insulation should be put over pipe and
better one over it
(c) both may be put in any order
(d) whether to put inferior OIL over pipe or the
better one would depend on steam temperature
(e) unpredictable.
Ans: a
61. Fourier's law of heat conduction is valid for
(a) one dimensional cases only
(b) two dimensional cases only
(c) three dimensional cases only
(d) regular surfaces having non-uniform
temperature gradients
(e) irregular surfaces.
Ans: a
62. According of Kirchhoff's law,
(a) radiant heat is proportional to fourth power of
absolute temperature
(b) emissive power depends on temperature
(c) emissive power and absorptivity are constant
for all bodies
(d) ratio of emissive power to absorptive power is
maximum for perfectly black body
(e) ratio of emissive power to absorptive power for
all bodies is same and is equal to the emissive
power of a perfectly black body.
Ans: e
63. All radiations in a black body are
(a) reflected
(b) refracted
(c) transmitted
(d) absorbed
(e) partly reflected and partly absorbed.
Ans: d
64. According to Kirchoff's law, the ratio of emissive
power to absorptivity for all bodies is equal to the
emissive power of a
(a) grey body
(b) brilliant white polished body
(c) red hot body
(d) black body
(e) none of the above.
Ans: d
65. The concept of overall coefficient of heat
transfer is used in case of heat transfer by
(a) conduction
(b) convection
(c) radiation
(d) conduction and convection
(e) convection and radiation.
Ans: d
66. The unit of overall coefficient of heat transfer is
(a) kcal/m2
(b) kcal/hr °C
(c) kcal/m2 hr °C
(4) kacl/m hr °C
(e) kcal/m3 hr °C.
Ans: c
68. Joule sec is the unit of
(a) universal gas constant
(b) kinematic viscosity
(c) thermal conductivity
(d) Planck's constant
(e) none of the above.
Ans: d
69. The value of Prandtl number for air is about
(a) 0.1
(b) 0.3
(c) 0.7
(d) 1.7
(e) 10.5.
Ans: c
70. The value of the wavelength for maximum
emissive power is given by —
(a) Wien's law
(b) Planck's law
(c) Stefan's law
(d) Fourier's law
(e) Kirchhoff's law.
Ans: a
72. Log mean temperature difference in case of
counter flow compared to parallel flow will be
(a) same
(b) more
(c) less
(d) depends on other factors
(e) none of the above.
Ans: b
73. The energy distribution of an ideal reflector at
higher temperatures is largely in the range of
(a) shorter wavelength
(b) longer wavelength
(c) remains same at all wavelengths
(d) wavelength has nothing to do with it
(e) none of the above.
Ans: a
74. Total emissivity of polished silver compared to
black body is
(a) same
(b) higher
(c) more or less same
(d) very much lower
(e) very much higher.
Ans: d
75. According to Stefan-Boltzmann law, ideal
radiators emit radiant energy at a rate proportional
to
(a) absolute temperature
(b) square of temperature
(c) fourth power of absolute temperature
(d) fourth power of temperature
(e) cube of absolute temperature.
Ans: c
76. Which of the following property of air does not
increase with rise in temperature
(a) thermal conductivity
(b) thermal diffusivity
(c) density
(d) dynamic viscosity
(e) kuiematic viscosity.
Ans: c
77. The unit of Stefan Boltzmann constant is
(a) watt/cm2 °K
(b) watt/cm4 °K
(c) watt2/cm °K4
(d) watt/cm2 °K4
(e) watt/cm2 °K2.
Ans: d
78. In free con-vection heat transfer, Nusselt
number is function of
(a) Grashoff no. and Reynold no.
(b) Grashoff no. and Prandtl no.
(c) Prandtl no. and Reynold no.
(d) Grashoff no., Prandtl no. and Reynold no.
(e) none of the above.
Ans: b
79. Stefan Boltzmann law is applicable for heat
transfer by
(a) conduction
(b) convection
(c) radiation
(d) conduction and radiation combined
(e) convection and radiation combined.
Ans: c
80. The thermal diffusivities for gases are generally
(a) more than those for liquids
(b) less than those for liquids
(c) more than those for solids
(d) dependent on the viscosity
(e) same as for the liquids.
Ans: a
81. The thermal diffusivities for solids are generally
(a) less than those for gases
(b) jess than those for liquids
(c) more than those for liquids and gases
(d) more or less same as for liquids and gases
(e) zerci.
Ans: c
83. Thermal diffusivity of a substance is
(a) directly proportional to thermal con¬ductivity
(b) inversely proportional to density of
substance
(c) inversely proportional to specific heat
(d) all of the above
(e) none of the above.
Ans: d
85. The ratio of the emissive power and absorptive
power of all bodies is the same and is equal to the
emissive power of a perfectly black body. This
statement is known as
(a) Krichoff's law
(b) Stefan's law
(c) Wien' law
(d) Planck's law
(e) Black body law.
Ans: a
86. According to Stefan's law, the total radiation
from a black body per second per unit area is
proportional to
(a) absolute temperature
(b) T2
(c) T5
(d) t
(e) l/T.
Ans: d
87. According to Wien's law, the wavelength
corresponding to maximum energy is proportion to
(a) absolute temperature (T)
(b) I2
(c) f
(d) t
(e) 1/r.
Ans: a
88. Depending on the radiating properties, a body
will be white when
(a) p = 0, x = 0 and a = 1
(b) p=l,T = 0anda = 0
(c) p = 0, x = 1 and a = 0
(d) x = 0, a + p = 1
(e) a = 0, x + p = 1.
where a = absorptivity, p = reflectivity, x =
transmissivity
Ans: b
89. Depending on the radiating properties, a body
will be black when
(a) p = 0, x = 0 and a = 1
(b) p= l,T = 0anda = 0
(c) p = 0, x = 1 and a = 0
(d) x = 0, a + p = 0
(e) a = 0,x + p= 1.
where a = absorptivity, p == reflectivity, X =
transmissivity.
Ans: a
90. Depending on the radiating properties, a body
will be opaque when
(a) p = 0, x = 0 and a = 1
(b) p=l,x = 0anda = 0
(c) p = 0, x = 1 and a = 0
(d) x - 0, a + p = 1
(e) a=0,x + p= 1.
where a = absorptivity, p = reflectivity, X =
transmissivity.
Ans: d
91. The total emissivity power is .defined as the
total amount of radiation emitted by a black body
per unit
(a) temperature
(b) thickness
(c) area
(d) time
(e) area and time.
Ans: d
92. The ratio of the energy absorbed by the body to
total energy falling on it is called
(a) absorptive power
(b) emissive power
(c) absorptivity
(d) emissivity
(e) none of the above.
Ans: a
93. 40% of incident radiant energy on the surface of
a thermally transparent body is reflected back. If
the transmissivity of the body be 0.15, then the
emissivity of surface is
(a) 0.45
(b) 0.55
(c) 0.40
(d) 0.75
(e) 0.60.
Ans: a
94. The amount of radiation mainly depends on
(a) nature of body
(b) temperature of body
(c) type of surface of body
(d) all of the above
(e) none of the above.
Ans: d
95. The emissive power of a body depends upon its
(a) temperature
(b) wave length
(c) physical nature
(d) all of the above
(e) none of the above.
Ans: d
96. Two plates spaced 150 mm apart are
maintained at 1000°C and 70°C. The heat transfer
will take place mainly by
(a) convection
(b) free convection
(c) forced convection
(d) radiation
(e) radiation and convection.
Ans: d
97. Absorptivity of a body will be equal to its
emissivity
(a) at all temperatures
(b) at one particular temperature
(c) when system is under thermal equi-librium
(d) at critical temperature
(e) for a polished body.
Ans: c
98. In regenerator type heat exchanger, heat
transfer takes place by
(a) direct mixing of hot and cold fluids
(b) a complete separation between hot and cold
fluids
(c) flow of hot and cold fluids alternately over a
surface
(d) generation of heat again and again
(e) indirect transfer.
Ans: c
99. A perfect black body is one which
(a) is black in colour
(b) reflects all heat
(c) transmits all heat radiations
(d) abslprbs heat radiations of all wave lengths
falling on it
(e) fully opaque.
Ans: d
100. Planck's law holds good for
(a) black bodies
(b) polished bodies
(c) all coloured bodies
(d) all of the above
(e) none of the above.
Ans: a
101. If the temperature of a solid surface changes
form 27°C to 627°C, then its emissive power
changes in the ratio of
(a) 3
(b) 6
(c) 9
(d) 27
(e) 81.
Ans: e
102. Depending on the radiating properties, body
will be transparent when
(a) p = 0, x = 0 and a = 1
(b) p=l,x = 0,anda = 0
(c) p = 0, T= l,anda = 0
(d) X = 0, a + p = 1
(e) a = 0,x + p= 1.
Ans: c
103. A grey body is one whose absorptivity
(a) varies with temperature
(b) varies with the wave length of incident ray
(c) varies with both
(d) does not vary with temperature and wave length
of the incident ray
(e) there is no such criterion.
Ans: d