Mechanical Engineer PPSC MCQs from PPSC Past Papers
Tolerance for a shaft of 50mm diameter as the basic size, with the fundamental deviation denoted by g and tolerance of grade 7 is represented as?
a) g50,7
b) 7g50
c) 50g7
d) None of the mention
Answer: 50g7
Which statement is not true for the cold working of metals?
A.residual stresses are set up in the metal
B.it reduces the corrosion resistance of the metal
C.stress required to cause deformation is less than the hot working of metals
D.distortion of grains takes place in most of the cold working processes
Answer: stress required to cause deformation is less than the hot working of metals
Select the facts that are true for resilience.
a) Ability of a material to absorb energy when deformed plastically
b) Ability to retain deformation under the application of load or after removal of load
c) Ability of a material to absorb energy when deformed elastically
d) None of these
Answer: c) Ability of a material to absorb energy when deformed elastically
The modulus of resilience is?
a) Independent of strain energy
b) Strain energy per unit area
c) Strain energy per unit volume
d) None of the mentioned
Answer: c) Strain energy per unit volume
rolling contact bearings are used in gearboxes and small size motors.
a) False
b) True
View Answer
Answer: b) True
In which of the following always give a positive clearance between the hole and the shaft over the complete span of tolerances?
a) Interference
b) Transition
c) Clearance
d) None of the mentioned
Answer: Clearance
Sliding contact bearings, also known as plain bearings have no problem of wear.
a) False
b) True
Answer: a) False
The rolling contact bearings are used in steam and gas turbines,
a) False
b) True
Answer: a) False
The temperature at which new strain-free cereal are formed in the metal is called the ______ temperature.
a) Crystallization
b) Recrystallization
c) Solidification
d) None of the mentioned
Answer: Recrystallization
Which statement is true for fundamental deviation?
a) Capital letter is used for both holes and shafts
b) Gives location of the tolerance zone
c) Small letter is used for both holes and shaft
d) None of the mentioned
Answer: a Gives location of the tolerance zone
Select the number of grades of tolerances is there according to BIS system fits and tolerances?
a) 12
b) 18
c) 16
d) 14
Answer: 18
Which is not better by the cold working of metals?
A.hardness
B.corrosion resistance
C.surface finish
D.toughness
Answer: corrosion resistance
Medals are constructed by
A.spinning
B.coining
C.embossing
D.bending
Answer: embossing
In which condition, the tolerance zone of the hole is totally under that of the shaft.
a) Clearance
b) Enjoining
c) Interference
d) None of the mentioned
Answer: Interference
The description of tolerances have of two parts specifically;
a) Magnitude of deviation and magnitude of tolerance
b) Fundamental deviation and magnitude of tolerance
c) Mean deviation and magnitude of tolerance
d) Fundamental deviation and tolerance
Answer: Fundamental deviation and magnitude of tolerance
Select the operation which can be performed on the lathe?
A.coining
B.drawing
C.spinning
D.swaging
Answer: spinning
Hot-working or cold working, which lessens tightness hardening and residual stresses.
a) Cold working
b) Hot working
c) Both have an equal effect
d) Impossible to detect
Answer: Hot working
Hot rolled components have a superior exterior finish than cold-rolled components.
a) True
b) False
Answer: False
The cold working of metal is expert at;
A.re-crystallization temperature
B.below re-crystallization temperature
C.below re-crystallization temperature
D.any of the above
Answer: below re-crystallization temperature
Tubes for shaving cream and toothpaste are made by
A.impact extrusion
B.backward extrusion
C.forward extrusion
D.all of the above
Answer: impact extrusion
Select the functions of bearings?
a) Ensure the free rotation of shaft with minimum friction
b) Transmit the force of the shaft to the frame
c) Holding shaft in a correct position
d) All of the above
Answer: d) All of the above
Wires are created by
A.spinning
B.embossing
C.drawing
D.bending
Answer: drawing
Select which one is not a classification of fit:
a) Clearance
b) Enjoining
c) Interference
d) Transition
Answer: Enjoining
A radial bearing helps the load that works along the axis of the shaft.
a) False
b) True
Answer: a) False
Select the bearing that provides supports the load acting along the axis of the shaft.
a) Longitudinal
b) Radial
c) Thrust
d) Transversal
Answer: c) Thrust
Select the truth about plasticity?
a) Permanent Deformation
b) Plastic deformation is greater than elastic deformation
c) Ability to retain deformation under load or after removal of load
d) All of the above
Answer: d) All of the above
Select the measure of stiffness?
a) Resilience
b) Modulus of plasticity
c) Modulus of elasticity
d) Toughness
Answer: c) Modulus of elasticity
