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Past Questions
Fluxes are used in welding in order to protect the molten metal and the surfaces to be jointed from -
A)
Oxidation
B)
Carburising
C)
Dit
D)
Distortion and warping
Flux removes/prevents oxides and shields the molten metal from atmospheric oxidation.
The SI unit of force is -
A)
Foot-Poundal
B)
Kef
C)
Dyne
D)
Newton
SI unit of force is Newton (kg·m/s2).
Tensile strength of the material is obtained by dividing the maximum load during the test by the -
A)
Area at the time of fracture
B)
Original cross-sectional area
C)
Average of (a) and (b)
D)
Minimum area after fracture
Tensile strength (ultimate tensile strength) is defined as the maximum load carried by a specimen divided by its original cross-sectional area. Therefore, the correct option is **b: Original cross-sectional area**.
Why the others are incorrect:
- **a. Area at the time of fracture**: tensile strength is not based on the fractured area; that would relate to fracture stress, not the standard tensile strength definition.
- **d. Minimum area after fracture**: this is the reduced area at the necked section after failure, not used for tensile strength calculation.
- **c. Average of (a) and (b)**: tensile strength is not computed using an average area; it specifically uses the original area before loading.
In acoupling rod of a locomotive, each of the four pairs is a pair.
A)
sliding
B)
rolling
C)
tuming
D)
screw
Coupling rod of locomotive forms four turning pairs in double crank mechanism.
Cutting tool can never have its -
A)
Clearance angle- positive
B)
Rake angle - positive
C)
Clearance angle- negative
D)
Rake angle - negative
A negative clearance angle would cause rubbing between the tool flank and workpiece; clearance must be non-negative in normal cutting.
Which of the following is used to form Complex shapes effectively?
A)
Metal casting
B)
Sand casting
C)
Powder metallurgy
D)
Turing
Correct answer: A. Metal casting is the option that matches the standard principle or definition asked.
Preheating is essential in welding -
A)
High speed steel
B)
Stainless steel
C)
Cast iron
D)
Aluminium
Cast iron is prone to cracking because of thermal stresses, so preheating is particularly important.
A ball and a socket forms a -
A)
Rolling pair
B)
Turning pair
C)
Screw pair
D)
Spherical pair
A ball-and-socket joint permits angular motion about multiple axes, so it is a spherical pair.
Ascrew is specified by -
A)
Major diameter x pitch
B)
Minimum diameter x length
C)
Major diameter x length
D)
Nominal major diameter
Screw specified by major diameter × pitch, bolt by diameter × length.
Water pipes of large length and diameter are made of -
A)
Semi-centrifugal casting
B)
Continuous casting
C)
Sand casting
D)
Electric resistance welding
Large-diameter, long steel water pipes are commonly produced by welding methods such as electric-resistance welding.
The yield point in static loading is as compared to fatigue loading.
A)
same
B)
lower
C)
higher
D)
approximately equal
The yield point under static loading is generally higher than the stress level associated with fatigue loading. In static loading, the material is loaded once or slowly, so yielding occurs at its normal yield strength. Under fatigue loading, repeated/cyclic stresses cause damage to accumulate and failure can occur at stresses well below the static yield point; hence the effective allowable stress in fatigue is lower. Therefore, compared to fatigue loading, the yield point in static loading is higher.
Why the other options are incorrect:
- a (same): Incorrect because static and fatigue loading do not have the same stress limit; cyclic loading reduces the effective safe stress.
- b (lower): Incorrect because static loading does not have a lower yield point than fatigue loading; it is typically higher.
- d (approximately equal): Incorrect because fatigue behavior is governed by repeated stress effects, so it is not approximately equal to static yield behavior.
Which of the following manufacturing process is favourable for making tool for ECM?
A)
Casting
B)
Shaping
C)
Cold forging
D)
Laser cutting
Correct answer: B. Shaping is the option that matches the standard principle or definition asked.
Which of the following is an example of hybrid machining?
A)
Ultrasonic machining
B)
Electron beam machining
C)
Laser beam machining
D)
Ultrasonic assisted electrochemical machining
Ultrasonic-assisted electrochemical machining combines more than one material-removal mechanism and is a hybrid process.
The shear modulus of most materials with respect to the modulus of elasticity is -
A)
Less than half
B)
More than half
C)
Equal to half
D)
More than one
For most engineering materials, the shear modulus (G) is related to Young’s modulus (E) by G = E / [2(1 + ν)], where ν is Poisson’s ratio. Since ν is usually positive and less than 0.5 for common materials, the denominator is greater than 2, so G is generally less than E/2. Hence, the correct option is 'Less than half.'
Why others are incorrect:
- b) More than half: Incorrect, because G is usually below E/2 for common materials.
- c) Equal to half: Incorrect, because that would only be true if ν = 0, which is not typical for most materials.
- d) More than one: Incorrect, because shear modulus and modulus of elasticity are different elastic constants and G is not generally greater than E.
The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in -
A)
Longitudinal vibrations
B)
Critical vibration
C)
Torsional vibrations
D)
Transverse vibrations
Critical speed of a shaft with a transverse deflection mode corresponds to the transverse natural vibration frequency.
The process of bevelling sharp ends of a workpiece is called as
A)
Knurling
B)
Facing
C)
Chamfering
D)
Grooving
Chamfering removes a sharp edge by making a bevel.
The strength of a cutting tool depends on the following angle -
A)
Lipangle
B)
Clearance angle
C)
Rake angle
D)
Cutting angle
The strength of a cutting tool mainly depends on the lip angle (also called the wedge angle). A larger lip angle gives a stronger cutting edge, while a smaller lip angle makes the tool weaker but easier to cut with. Hence, lip angle is the key angle governing tool strength.
Why the others are incorrect:
- Cutting angle: This is not the primary angle used to describe the strength of the cutting edge.
- Clearance angle: This prevents rubbing between tool and workpiece; it affects friction and finish, not tool strength.
- Rake angle: This mainly affects chip flow and cutting forces; it influences cutting action, but not the strength of the tool edge as directly as lip angle.
The loss of strength in compression due to overloading is known as -
A)
Hysteresis
B)
Creep
C)
Bouschinger effect
D)
Resilience
The correct answer is **Bauschinger effect**. It refers to the reduction in yield/strength in one direction (such as compression) after the material has been previously stressed or overloaded in the opposite direction, due to internal stress changes and dislocation movement. This is the phenomenon associated with loss of strength in compression due to prior overloading.
Why the others are incorrect:
- **Resilience**: the ability of a material to absorb and store elastic energy; it is not a loss of strength phenomenon.
- **Hysteresis**: the lag between loading and unloading, often seen in stress-strain behavior, but it does not specifically mean loss of compressive strength due to overloading.
- **Creep**: the time-dependent permanent deformation under sustained load, not the specific reduction in strength caused by overloading.
Which of the following software is used to provide the users with various functions to perform geometric modelling and construction?
A)
Graphics software
B)
Programming software
C)
Operating software
D)
Application software
Graphics/CAD software provides geometric modelling and construction functions.
Work study is most useful -
A)
Where production activities are involved
B)
In judging the rating of machines
C)
Inimproving industrial relations
D)
Injudging the output of a man and improving it
Correct answer: D. Injudging the output of a man and improving it is the option that matches the standard principle or definition asked.
Gnatt chart provides information about -
A)
Material handling
B)
Proper utilisation of manpower
C)
Production schedule
D)
Efficient working of machine
Correct answer: C. Production schedule is the option that matches the standard principle or definition asked.
Which type of gear train is used in clock mechanism to join hour hand and minute hand?
A)
Compound gear train
B)
Epicyclic gear train
C)
Simple gear train
D)
Reverted gear train
A reverted gear train keeps the input and output shafts parallel and is used to bring the clock hands onto the same axis.
The term ‘effort of governor’ refers to -
A)
Centrifugal force of balls
B)
Useful power developed
C)
Force acting on sleeve for given percentage change of speed
D)
Minimum force required on sleeve for percentage change of speed
Governor effort is the mean force required at the sleeve for a specified percentage change in speed.
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
Correct answer: A. Normal time + allowances is the option that matches the standard principle or definition asked.
The columns whose slenderness ratio is less than 80, are known as -
A)
Medium columns
B)
Long columns
C)
Weak columns
D)
Short columns
Short columns <80, medium 80-120, long >120 by slenderness ratio classification.