Engineering Online MCQ Number 0439 – online study, assignment and exam

Multiple choice question for engineering

Set 1

1. In which welding process the electric energy required for welding is stored in the capacitor?
a) Percussion welding
b) Explosion welding
c) Diffusion welding
d) Thermit welding

Answer

Answer: a [Reason:] Percussion welding process the electric energy required for welding is stored in the capacitor. It is a non conventional process of welding.

2. In which welding process pressure is applied by detonating a layer of explosive?
a) Precussion welding
b) Explosion welding
c) Diffusion welding
d) Thermit welding

Answer

Answer: b [Reason:] In explosion welding process pressure is applied by detonating a layer of explosive. It is a non conventional process of welding.

3. In which welding the surfaces of two components are subjected to static normal force and oscillating shear stress?
a) Diffusion welding
b) Thermit welding
c) Laser beam welding
d) Ultrasonic welding

Answer

Answer: d [Reason:] In ultrasonic welding the surfaces of two components are subjected to static normal force and oscillating shear stress. It is a non conventional process of welding.

4. In which welding the strength of the weld results due to diffusion and plastic deformation of the flying surface?
a) Diffusion welding
b) Thermit welding
c) Laser beam welding
d) Ultrasonic welding

Answer

Answer: a [Reason:] In diffusion welding the strength of the weld results due to diffusion and plastic deformation of the flying surface. It is a non conventional process of welding.

5. In Thermit welding the heat generated is due to the mixing of?
a) Aluminum and copper
b) Aluminum and iron
c) Aluminum oxide and iron
d) Aluminum and iron oxide

Answer

Answer: d [Reason:] In thermit welding the heat generated is due to the mixing of Aluminum and iron oxide. It is a conventional process of welding.

6. Which of the following welding is also known as arc and gas welding?
a) Electro slag welding
b) Atomic hydrogen welding
c) Laser beam welding
d) Ultrasonic welding

Answer

Answer: b [Reason:] Atomic hydrogen welding is also known as arc and gas welding. It is a conventional process of welding.

7. Which of the following welding is used for welding vertical section in one pass?
a) Electro slag welding
b) Atomic hydrogen welding
c) Laser beam welding
d) Electro gas welding

Answer

Answer: d [Reason:] Electro gas welding is used for welding vertical section in one pass. It is a conventional process of welding.

8. Electron beam welding is carried out in?
a) Inert atmosphere
b) Partially filled chamber
c) Vacuum
d) Partially vacuum

Answer

Answer: c [Reason:] Electron beam welding is carried out in vacuum. It is a non conventional process of welding.

9. In which of the following welding process the joint is obtained by means of fileer material and not by melting?
a) Diffusion welding
b) Thermit welding
c) Electroslag welding
d) Brazing

Answer

Answer: d [Reason:] In brazing welding process the joint is obtained by means of filler material and not by melting.

10. Which of the following statements is true?
a) Brazing occurs at a temperature above 450 Celsius
b) Soldering occurs at a temperature below 450 Celsius
c) Epoxy resins are used to join metals, ceramics etc
d) All of the Mentioned

Answer

Answer: d [Reason:] Brazing and soldering occurs at very high very high temperature. They are used in joining of two metal.

Set 2

1. Injection moulding is a type of
a) Die casting
b) Centrifugal casting
c) Squeeze casting
d) Investment casting

Answer

Answer: a [Reason:] Injection moulding is a type of die casting. It is widely used in plastic processing method. It is similar to die casting.

2. Which of the following problem is not correct about die casting?
a) It has close dimensional accuracy
b) Die has good life
c) It is very economical for large scale production
d) No need for removing the entrapped gases

Answer

Answer: d [Reason:] Entrap air ends up inside the casting. So it causes defect. It has close dimensional accuracy. It is very economical for large scale production.

3. Which type of casting is preferred for making hollow pipes and tubes which are axisymmetric with concentric holes?
a) Centrifuging
b) True centrifugal casting
c) Semi-centrifugal casting
d) None of the mentioned

Answer

Answer: b [Reason:] For making hollow pipes and tubes which are axisymmetric with concentric holes true centrifugal casting is preferred.

4. Which of the following casting is a combination of casting and forging?
a) Die casting
b) Centrifugal casting
c) Squeeze casting
d) Investment casting

Answer

Answer: c [Reason:] Squeeze casting is a combination of casting and forging. Die casting has close dimensional accuracy. It is very economical for large scale production.

5. In plaster mould casting the mould is made from
a) CaSO4
b) CaSO3
c) CaSO2
d) None of the mentioned

Answer

Answer: a [Reason:] The mould is made from plaster of Paris whose chemical formula is CaSO4 Where Ca is calcium, S is sulphur and O represents oxygen.

6. In which casting process the sand is mixed with a thermosetting resin to form a mould?
a) Die casting
b) Centrifugal casting
c) Squeeze casting
d) Shell moulding

Answer

Answer: d [Reason:] In shell moulding process the sand is mixed with a thermosetting resin to form a mould. Thermosetting plastic can’t used again when remelted.

7. The resins used in shell moulding are?
a) Diphenyl aldehyde
b) Phenol formaldehyde
c) Methyl formaldehyde
d) Dimethyl formaldehyde

Answer

Answer: b [Reason:] The resins used in shell moulding are phenol formaldehyde. Shell moulding comes in special casting processes.

8. Which casting is used to make hollow casting with thin walls?
a) Die casting
b) Centrifugal casting
c) Slush casting
d) Shell moulding

Answer

Answer: c [Reason:] Slush casting is used to make hollow casting with thin walls. Slush casting comes in special casting processes. Slush casting is also known as hollow casting.

9. In investment casting process which of the following is used for pattern making?
a) Ceramics
b) Molten wax
c) Silica
d) Plaster of paris

Answer

Answer: b [Reason:] In investment casting process molten wax is used for pattern making. It is costly process but have a very good dimensional accuracy.

10. Which of the following are the examples of precision casting process?
a) Plastic mould casting
b) Ceramic mould casting
c) Investment casting
d) All of the mentioned

Answer

Answer: d [Reason:] Plastic mould casting, ceramic mould casting, investment casting are the examples of precision casting process.

Set 3

1. Crater wear occurs mainly on the
a) nose part, front relief face and side relief face of the cutting tool
b) face of the cutting tool at a short distance from the cutting edge only
c) cutting edge only
d) front face only

Answer

Answer: b [Reason:] Crater wear occurs on the rake face of the tool, while flank wear occurs on the relief (flank) face of the tool.

2. Flank wear depends upon the
a) hardness of the work and tool material at the operating temperature
b) amount and distribution of hard constituents in the work material
c) degree of strain hardening in the chip
d) none of the mentioned

Answer

Answer: b [Reason:] Flank wear occurs as a result of friction between the progressively increasing contact area on the tool flank.

3. Crater wear is predominant in
a) carbon steels
b) tungsten carbide tools
c) high speed steel tools
d) ceramic tools

Answer

Answer: b [Reason:] Crater wear is usually found while machining brittle materials and tungsten carbide tools favour this phenomenon.

4. Flank wear is due to the abrasive action of hard mis-constituents.
a) True
b) False

Answer

Answer: a [Reason:] Flank wear is due to the abrasive action of hard mis-constituents including debris from built up edge as the work material rubs the work surface.

5. Crater wear is mainly due to the phenomenon known as
a) adhesion of metals
b) oxidation of metals
c) diffusion of metals
d) none of the mentioned

Answer

Answer: c [Reason:] Flank wear is due to the abrasive action and crater wear is due to diffusion of metals.

6. Crater wear leads to
a) increase in cutting temperature
b) weakening of tool
c) friction and cutting forces
d) all of the mentioned

Answer

Answer: d

7. Crater wear is usually found while machining ductile materials.
a) True
b) False

Answer

Answer: b [Reason:] Crater wear is usually found while machining brittle materials.

8. The tool may fail due to
a) cracking at the cutting edge due to thermal stresses
b) chipping of the cutting edge
c) plastic deformation of the cutting edge
d) all of the mentioned

Answer

Answer: d

9. Flank wear occurs mainly on the
a) nose part, front relief face and side relief face of the cutting tool
b) face of the cutting tool at a short distance from the cutting edge only
c) cutting edge only
d) front face only

Answer

Answer: a [Reason:] Crater wear occurs on the rake face of the tool, while flank wear occurs on the relief (flank) face of the tool.

10. Tool life is measured by the
a) number of pieces machined between tool sharpenings
b) time the tool is in contact with the job
c) volume of material removed between tool sharpenings
d) all of the mentioned

Answer

Answer: d

11. The tool life is said to be over if
a) poor surface finish is obtained
b) there is sudden increase in cutting forces and power consumption
c) overheating and fuming due to heat of friction starts
d) all of the mentioned

Answer

Answer: d

12. Tool life is generally better when
a) grain size of the metal is large
b) grain size of the metal is small
c) hard constituents are present in the micro structure of the tool material
d) none of the mentioned

Answer

Answer: a

13. The relation between the tool life(T) in minutes and cutting speed (V) in m/min is
a) VnT = C
b) VTn = C
c) Vn/T = C
d) V/Tn = C

Answer

Answer: b

14. Using the Taylor Equation for tool life and letting n = 0.5 and C = 120, calculate the percentage increase in tool life when the cutting speed is reduced by 50%.
a) 100%
b) 200%
c) 300%
d) 400%

Answer

Answer: c [Reason:] Since n = 0.5, the Taylor equation can be rewritten as VT0.5 = 120.

Let’s denote V1 as the initial speed and V2 the reduced speed; thus, V2 = 0.5 V1. Because C is the constant 120, we have the relationship
0.5V1 sqrt T2 = V1sqrt T1

Simplifying this equation, T2/T1 = 1/0.25 = 4. This
indicates that the change in tool life is
(T2 – T1/ T1) = (T2/T1) – 1 = 4 – 1 = 3,

or that tool life is increased by 300%. Thus, a reduction in cutting speed has resulted in a major increase in tool life. Note also that, for this problem, the magnitude of C is not relevant.

Set 4

1. Pinch effect in welding is the result of?
a) Electro-magnetic forces
b) Electro-static force
c) Magnetic forces
d) Electric forces

Answer

Answer: a [Reason:] Pinch effect in welding is the result of electro-magnetic forces. It is encountered in process where electrodes are used for welding process.

2. Junction between weld face and base metal is known as?
a) Throat
b) Toe
c) Root
d) Puddle

Answer

Answer: b [Reason:] Junction between weld face and base metal is known as toe. For better welding junction should be small in size. Junction between two work piece and weld face is known as throat.

3. Junction between two work piece and weld face is known as?
a) Throat
b) Toe
c) Root
d) Puddle

Answer

Answer: a [Reason:] Junction between two work piece and weld face is known as throat. Junction between weld face and base metal is known as toe. For better welding junction should be small in size.

4. Portion at which two work piece are at the nearest distance is called as?
a) Throat
b) Toe
c) Root
d) Puddle

Answer

Answer: c [Reason:] Portion at which two work piece are at the nearest distance is called as root. It can be said base of two work piece.

5. The portion of weld joint that is melted by the heat of melting is called as?
a) Throat
b) Toe
c) Root
d) Puddle

Answer

Answer: d [Reason:] The portion of weld joint that is melted by the heat of melting is called as puddle. Heat is generated in heat affected zone.

6. Small weld used to temporally hold the two pieces is called as?
a) Crater
b) Base metal
c) Tack weld
d) Penetration

Answer

Answer: c [Reason:] Small weld used to temporally hold the two pieces is called as tack weld. It generally have smaller strength.

7. What is the function of torch?
a) It controls fuel rate
b) It mixes fuel and oxygen and controls delivery
c) It controls oxygen rate
d) None of the Mentioned

Answer

Answer: b [Reason:] Torch mixes fuel and oxygen and controls delivery. It have two control valves for acetylene and hydrogen. It has a mixing chamber.

8. The depth up to which the filler material is mixed up with base metal is called as?
a) Deposition
b) Reinforcement
c) Penetration
d) Fusion depth

Answer

Answer: c [Reason:] The depth up to which the filler material is mixed up with base metal is called as penetration. Penetration can be increased by increasing temperature and appropriate flux.

9. Weld pass is associated with the movement of?
a) Torch
b) Metal
c) Flux
d) Electrode

Answer

Answer: a [Reason:] Weld pass is associated with the movement of torch. Movement of torch in a particular direction is regarded as weld pass.

10. The raised portion from the parent metal in welding is known as?
a) Deposition
b) Fusion depth
c) Penetration
d) Reinforcement

Answer

Answer: d [Reason:] The raised portion from the parent metal is known as reinforcement. This part can be machined to make good surface finish.

Set 5

1. Which of the following defects occur due to flux employed and electrode coating?
a) Inclusion of slay
b) Inadequate penetration
c) Incomplete fusion
d) Porosity

Answer

Answer: a [Reason:] Inclusion of slay defects occur due to flux employed and electrode coating. Slag is formed by reaction of flux. Stirring action may force slag to weld pool.

2. Which of the following defects occur when the deposited metal are not focused at the root of weld?
a) Inclusion of slay
b) Inadequate penetration
c) Incomplete fusion
d) Porosity

Answer

Answer: b [Reason:] Inadequate penetration defects occur when the deposited metal are not focused at the root of weld. Some part of gap remain unwelded due to this defect.

3. Which of the following defects occur when weld metal layer fail to fuse together?
a) Inclusion of slay
b) Inadequate penetration
c) Incomplete fusion
d) Porosity

Answer

Answer: c [Reason:] Incomplete fusion defects occur when weld metal layer fail to fuse together. It cause discontinuity in weld zone.

4. Which of the following defects occur due to the entrapment of gas bubbles by the freezing dendrites during the cooling of molten pad?
a) Inclusion of slay
b) Inadequate penetration
c) Incomplete fusion
d) Porosity

Answer

Answer: d [Reason:] Porosity defect occur due to the entrapment of gas bubbles by the freezing dendrites during the cooling of molten pad.

5. Which of the following defects occur due to filler material having different rate of contraction compared to parent metal?
a) Under cut
b) Spatter
c) Cracking in weld metal
d) Cold cracking

Answer

Answer: c [Reason:] It occurs generally at high temperatures and it may be hardly visible. Cracking in weld metal defect occur due to filler material having different rate of contraction compared to parent metal.

6. Which of the following defects occur due to melting or burning away of base metal?
a) Under cut
b) Spatter
c) Cracking in weld metal
d) Cold cracking

Answer

Answer: a [Reason:] Undercut appear like small, undercut defects occur due to melting or burning away of base metal.

7. Which of the following defects occur due to scattering of metal around the vicinity of weld?
a) Under cut
b) Spatter
c) Cracking in weld metal
d) Cold cracking

Answer

Answer: b [Reason:] Spatter defects occur due to scattering of metal around the vicinity of weld. It causes poor surface finish.

8. Which of the following defects occur due to incorrect welding techniques?
a) Under cut
b) Hot cracking
c) Cracking in weld metal
d) Cold cracking

Answer

Answer: c [Reason:] Cracking in weld metal defect occur due to incorrect welding techniques. Some time cracking may not be visible by naked eyes.

9. Which of the following defect is influenced by sulphur and carbon content of weld metals?
a) Under cut
b) Hot cracking
c) Cracking in weld metal
d) Cold cracking

Answer

Answer: b [Reason:] Hot cracking defect is influenced by sulphur and carbon content of weld metals. Some time cracking may not be visible by naked eyes.

10. Which of the following defects occur at lower temperature?
a) Under cut
b) Hot cracking
c) Cracking in weld metal
d) Cold cracking

Answer

Answer: d [Reason:] Cold cracking defect occur at lower temperature. Some time cracking may not be visible by naked eyes.