Engineering Online MCQ Number 0400 – online study, assignment and exam

Multiple choice question for engineering

Set 1

1. Resilience is defined as the property of material to absorb energy when deformed _________ and to release this energy when unloaded.
a) Elastically
b) Plastically
c) Up to fracture point
d) None of the listed

Answer

Answer: a [Reason:] It is the definition of resilience.

2. The shock absorbing capacity of bolt can be increased by making the shank diameter ________ the root diameter.
a) Lesser than
b) Equal to
c) Greater than
d) No effect

Answer

Answer: b [Reason:] If shank diameter is equal to the thread diameter than, the shank is subjected to higher stress and thus absorbs a great portion of strain energy and relieves the thread portion of high stress.

3. The shock absorbing capacity of bolts can be increased by
a) Increasing the shank diameter
b) Decreasing the length of shank portion of bolt
c) Increase the shank diameter and decreasing the length of shank
d) None of the listed

Answer

Answer: d [Reason:] Shock absorbing capacity can be increased by decreasing the shank diameter or increasing the length of shank.

4. If the length of the shank is doubled, then strain energy absorbed by shank
a) Doubles
b) Remains same
c) Increases 4 time
d) Become half

Answer

Answer: a [Reason:] Strain energy absorbed by shank is linearly proportional to its length.

5. Which of the following help in accomplishing the locking?
a) Creating supplementary friction
b) Using special locking devices like split pins
c) By plastic deformation
d) All of the listed

Answer

Answer: d [Reason:] All the methods can be employed to lock the screw.

6. Crests and roots of the threads may lead to leakage in fluid tight threads if flattened or rounded to a circular arc.
a) True
b) False

Answer

Answer: b [Reason:] As there is engagement in the threads, chances of leakage are reduced.

7. The static load carrying capacity of fine threads is greater than that of coarse threads.
a) True
b) False

Answer

Answer: b [Reason:] Coarse threads have a higher load carrying capacity.

8. Coarse threads have helix angle _____ fine threads.
a) Equal to
b) Greater than
c) Lesser than
d) There is no relation

Answer

Answer: c [Reason:] Finer threads have lower helix angle.

9. Which threads have greater resistance to unscrewing?
a) Coarse
b) Fine
c) They have equal resistance
d) Cannot be determined

Answer

Answer: b [Reason:] Fine threads have greater resistance to unscrewing as a result of lower helix angle.

10. Which type of threads is recommended for fluctuating loads?
a) Fine threads
b) Coarse Threads
c) Either of fine or coarse
d) None of the listed

Answer

Answer: a [Reason:] Fine threads have lesser helix angle and hence greater resistance for unscrewing and thus are recommended for fluctuating loads.

Set 2

1. All welding processes require pressure along with heat.
a) Yes
b ) No, fusion doesn’t require
c) Can’t be stated
d) None of the listed

Answer

Answer: b [Reason:] Welding processes involving only heat and no pressure are called the fusion welding processes.

2. The capacity of welded structures to damp vibrations is quite good.
a) True
b) False

Answer

Answer: b [Reason:] Capacity of welded joints to damp vibrations is poor.

3. Themit consists of a finely divided mixture of iron oxide and copper.
a) True
b) False

Answer

Answer: b [Reason:] Thermite is a mixture of iron oxide and copper.

4. Rails in the field are generally welded by using
a) Thermit welding
b) Gas welding
c) Electric arc welding
d) Forge welding

Answer

Answer: a [Reason:] Wherever it is uneconomical to carry welding equipments, thermit welding is used.

5. In gas welding which of the following is generally used?
a) Oxygen-Hydrogen
b) Oxygen-Acetylene
c) Oxygen-Hydrogen or Oxygen-Acetylene
d) None of the mentioned

Answer

Answer: c [Reason:] Intense heat is released I a controlled way and at a moderate temperature.

6. Among gas and electric arc welding, which has the higher rate of heating?
a) Gas welding
b) Electric arc welding
c) Gas welding and electric arc welding have equal rate of heating
d) Cannot be determined

Answer

Answer: b [Reason:] Gas welding has a gas temperature of about 3200’C while arc temperature is about 40000’C.

7. Forge welding involves heating of parts to elastic stage and joint is prepared by impact force.
a) Yes
b) No, it is done up to plastic stage
c) Heating is done up to boiling point
d) None of the listed

Answer

Answer: b [Reason:] Heating is done up to plastic stage.

8. Filler material is used in electric resistance welding.
a) Yes
b) No filler material used
c) Depends on the type of welding
d) None of the listed

Answer

Answer: b [Reason:] No filler material is used. Only the heat released from resistance of metallic parts to current is used for melting the adjoining parts.

9. Which type of welding is generally used in automobile sector?
a) Electric arc welding
b) Electric resistance welding
c) Gas welding
d) Forge welding

Answer

Answer: b [Reason:] Electric resistance welding can be easily automated and hence is used in automobile sector.

10. Hard peening is
a) Hammering the weld across the length while the joint is hot
b) Hammering the weld along the length while the joint is hot
c) Hammering the weld along the length while the joint is cold
d) Hammering the weld across the length while the joint is cold

Answer

Answer: b [Reason:] Hammering is doe to relieve stresses and inducing compressive stresses to improve the fatigue strength of the joint.

Set 3

1. In which run weld, in ordinary steels, the grain refinement takes place?
a) First
b) Second
c) Third
d) Fourth

Answer

Answer: b [Reason:] A multi run process causes a good amount of grain refinement. With every proceeding run weld, it normalizes its previous run. In ordinary steels, grain refinement takes place in the second run.

2. What is the minimum strength of mild steel arc welds on addition of microelements in the slag?
a) 43 kgf/mm2
b) 39 kgf/mm2
c) 45kgf/mm2
d) 48 kgf/mm2

Answer

Answer: a [Reason:] When there is an addition of some microelements in the slag along with a few materials being present which are not metals, there is an increase in the strength of the mild steel arc weld. The minimum amount of strength goes up to 43 kgf/mm2, which is 430 N/mm2.

3. Which of the following is affected by weld contour?
a) Fatigue
b) Creep
c) High pressure property
d) Low pressure property

Answer

Answer: a [Reason:] The contour present on the welds form notches. The contours in the form of notches then affect the low temperature properties of the structure and also the fatigue properties.

4. Thermite contains which metal?
a) Zinc
b) Copper
c) Aluminium
d) Manganese

Answer

Answer: c [Reason:] The reaction that takes place in between compounds and elements is known welding with solid reactants. These reaction are exothermic, that is give out heat as a product. Thermit reaction is a common example for this, which is mixture of aluminium and rust.

5. Which of the following property is considered for controlling the porosity of the metal?
a) Solid solubility
b) Liquid solubility
c) Gas solubility
d) Flame solubility

Answer

Answer: c [Reason:] The amount of solubility of gas in liquid or solid welded metals is considered to be an essential criteria for the control of porosity of the weld. The gas reactions which occur, then regulate porosity.

6. Slag used in fusion welding contains manganese.
a) True
b) False

Answer

Answer: a [Reason:] Slags used in welding are generally a combination of silica materials and some carbonate compounds. In fusion welding, some amount of bead control has to be done, which is done by the slags, for this purpose, to improve its performance, microelements like manganese are added.

7. Which of the following property is responsible for weld metal cracking?
a) Stress
b) Strain
c) Temperature conditions
d) Pressure conditions

Answer

Answer: a [Reason:] The stresses which get developed in welding during shrinkage are of importance. These stresses are considered to be an important factor which are responsible for the cracking that occurs in metal welds.

8. A thermit reaction produces heat up to what temperature?
a) 4800°F
b) 4000°F
c) 5600°F
d) 5300°F

Answer

Answer: b

9. What is the maximum strength of mild steel arc welds on addition of microelements in the slag?
a) 53 kgf/mm2
b) 49 kgf/mm2
c) 57kgf/mm2
d) 61 kgf/mm2

Answer

Answer: c [Reason:] When there is an addition of some microelements in the slag along with a few nonmetallic inclusions, there is an increase in the strength of the mild steel arc weld. The maximum amount of strength goes up to 57 kgf/mm2, which is 570 N/mm2.

10. Slag used in fusion welding has nitrogen.
a) True
b) False

Answer

Answer: a [Reason:] Slags used in welding are generally a combination of silica materials and some carbonate compounds. In fusion welding, some amount of bead control has to be done, which is done by the slags, for this purpose, to improve its performance, microelements like nitrogen are added.

Set 4

1. What is the order of temperature of heat produced in an electric arc furnace?
a) 3000°C – 4000°C
b) 4000°C – 5000°C
c) 5000°C – 6000°C
d) 6000°C – 7000°C

Answer

Answer: d [Reason:] An electric arc furnace generates a lot of heat when the working metal comes in contact with the electrode. The heat that is generated in this joining process is of the order 6000°C to 7000°C.

2. The distance from the center of arc to the tip of electrode is called what?
a) Arc distance
b) Arc length
c) Arc crater
d) Arc depth

Answer

Answer: b [Reason:] The distance from the center of the arc to the tip of the electrode, right till the bottom of the crater is defined to be the arc length. The arc length is considered to be one of the most essential variable in welding process.

3. What is the length of the arc generally?
a) 1mm – 2mm
b) 2mm – 3mm
c) 3mm – 4mm
d) 4mm – 5mm

Answer

Answer: c

4. In arc welding process, the high quality alternator functions at what frequency?
a) 250 Hz
b) 300 Hz
c) 350 Hz
d) 400 Hz

Answer

Answer: d [Reason:] In an arc welding process, there are alternators used for producing high current and function at lower frequency, and there are alternators which are of high quality and work at high frequency. The functioning frequency of these alternators is 400 Hz.

5. Which type of electrode is designed for melting quickly?
a) Fast fill
b) Fast freeze
c) Quick fill
d) Fill freeze

Answer

Answer: a [Reason:] Electrodes which are classified into three types, fast fill, fast freeze and fill freeze. Among these, the fast fill electrodes are considered to be able to operate at extremely high welding speeds, and hence fast fill electrodes are designed for quick melting.

6. What amount of electricity gets converted into heat energy in an arc welding process?
a) 0.25 kWh
b) 0.75 kWh
c) 1 kWh
d) 2 kWh

Answer

Answer: c [Reason:] In an arc welding process, there is a direct conversion of electrical energy into heat energy. An approximate amount of 1 kilo Watt hour of electrical energy gets converted into heat energy for this process.

7. Arc welding machine uses only D.C. supply.
a) True
b) False

Answer

Answer: b [Reason:] Arc welding machines are able of working on both alternating current supply as well as direct current supply. But mainly arc welding machines work on D.C. supply only, where the positive terminal is connected to the welding machine.

8. Which type of electrode is designed for melting quickly?
a) Fast fill
b) Fast freeze
c) Quick fill
d) Fill freeze

Answer

Answer: b [Reason:] Electrodes which are classified into three types, fast fill, fast freeze and fill freeze. In fast freeze electrodes, a filler metal is supplied. This filler element gets solidifies and provides a variety in positions of the weld.

9. Which material is not used as an iron coating on the electrode used in arc welding?
a) Cellulose
b) Iron powder
c) Calcium fluoride
d) Steel

Answer

Answer: d [Reason:] Materials that are used as coating on the electrode, that are used in arc welding, are cellulose, iron powder, calcium fluoride and rutile. Iron is used for ease of weld, but not steel, though it mainly contains iron.

10. The negative pole of the electrode burns away faster than the positive pole.
a) True
b) False

Answer

Answer: b [Reason:] During the operation of the arc welding process, the positive pole of the electrode experiences two third of the heat and the negative pole experiences one third the heat, hence the positive pole burns away faster than the negative pole.

Set 5

1. In an iron thermit, how many moles of aluminium reacts with three moles of iron oxide to give nine moles of iron?
a) 6
b) 7
c) 8
d) 9

Answer

Answer: c [Reason:] The thermit process, which is used for welding depends on the chemical reaction between oxide of iron and aluminium metal. According to this reaction, when 8 moles of aluminium reacts with 3 moles of iron oxide, then, 4 moles of aluminium oxide and 9 moles of iron is formed.

2. In the given figure of thermit welding apparatus, what does the question mark represents which part?
welding-multiple-choice-questions-answers-q2
a) Sand plug
b) Crucible
c) Wax pattern
d) Slag basin

Answer

Answer: b [Reason:] Around the parts which are to be united, superheated liquid steel is poured, which then effects in forming the weld. This process, hence, is a fusion welding process. The part represented by the question mark is the crucible.

3. In the given figure of thermit welding apparatus, what does the question mark represents which part?
welding-multiple-choice-questions-answers-q3
a) Sand plug
b) Crucible
c) Wax pattern
d) Slag basin

Answer

Answer: d

4. In the given figure of thermit welding apparatus, what does the question mark represents which part?
welding-multiple-choice-questions-answers-q4
a) Riser
b) Workpiece
c) Runner
d) Wax pattern

Answer

Answer: d [Reason:] In this apparatus of the thermit welding process, the question mark here represents the pattern made up of wax. This process is basically carried out in fusion welding.

5. In the given figure of thermit welding apparatus, what does the question mark represents which part?
welding-multiple-choice-questions-answers-q5
a) Riser
b) Workpiece
c) Runner
d) Wax pattern

Answer

Answer: b

6. In the given figure of thermit welding apparatus, what does the question mark represents which part?
welding-multiple-choice-questions-answers-q6
a) Riser
b) Workpiece
c) Runner
d) Wax pattern

Answer

Answer: c [Reason:] In this figure, the question mark is represented by the runner. This process is carried out at fusion welding.

7. In the given figure of thermit welding apparatus, what does the question mark represents which part?
welding-multiple-choice-questions-answers-q7
a) Riser
b) Runner
c) Sand plug
d) Preheating

Answer

Answer: c [Reason:] The part represented by the question mark is the sand plug. Superheated liquid steel is poured, which then effects in forming the weld. This process, hence, is a fusion welding process.

8. After the achievement of welding temperature, electrical connections are established to complete the weld.
a) True
b) False

Answer

Answer: b [Reason:] The superheated melt is heated from the crucible gets poured around the metal parts. As the welding temperature is achieved, there is an application of mechanical pressure to the weld.

9. What is the magnitude of temperature produced in a thermit reaction?
a) 2500°C
b) 3000°C
c) 3500°C
d) 4000°C

Answer

Answer: b [Reason:] Thermit welding is called as fusion welding. A superheated melt operates in this type of melt. The heat that is produced has the temperature approximately twice than that of the melting point of steel, which is about 3000°C.

10. Thermit welding is used for making rail tracks.
a) True
b) False

Answer

Answer: a [Reason:] A superheated melt operates in this type of melt. The production of pipes, rail tracks, shafts or big gears can be done using thermit pressure welding. Thermit welding is called as fusion welding.