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Multiple choice question for engineering

Set 1

1. Worm gear drives are used to transmit power between two non-intersecting shafts which are generally at right angles to each other.
a) True
b) False

View Answer

Answer: a [Reason:] This is how the worm gear design fits into use.

2. The worm and worm wheel both are threaded screw.
a) True
b) Worm wheel is a toothed gear
c) Worm is a toothed gear
d) None of the listed

View Answer

Answer: b [Reason:] Worm wheel is a toothed gear.

3. Which of the following is not true about worm gears?
a) Compact
b) Smooth and silent operation
c) Low speed reduction
d) All the mentioned are true

View Answer

Answer: c [Reason:] Speed reduction can be high up to 100:1.

4. Is it possible to use worm gears in cranes for lifting purpose?
a) True
b) No self-locking and hence not possible
c) Possible up to a threshold load
d) None of the listed

View Answer

Answer: a [Reason:] Worm gears support self-locking operation and hence are advantageous to use in lifting operations.

5. The power transmitting capacity of worm gears is high although efficiency is low.
a) True
b) False

View Answer

Answer: b [Reason:] Both power transmitting capacity and efficiency of worm gears are low.

6. Can worm gears be used in steering mechanism?
a) True
b) False

View Answer

Answer: a [Reason:] In steering mechanism, efficiency is of little importance but major requirement is of large mechanical advantage.

7. The worm helix angle is the _____ of the worm lead angle.
a) Complement
b) Half
c) Double
d) Supplement

View Answer

Answer: a [Reason:] Worm helix angle+worm lead angle=90⁰.

8. If worm helix angle is 30⁰, then worm should have at least ___ threads.
a) 5
b) 6
c) 7
d) 8

View Answer

Answer: a [Reason:] The permissible helix angle is 6⁰ and hence there should be at least five threads i.e. 30/6.

9. A pair of worm gear is written as 2/40/12/6. Calculate the centre distance.
a) 40mm
b) 156mm
c) 200mm
d) 80mm

View Answer

Answer: b [Reason:] C=m(q+z)/2 where m=6mm, q=12 and z=40.

10. A pair of worm gear is written as 2/40/12/6. Calculate the speed reduction.
a) 2
b) 20
c) 15
d) 6

View Answer

Answer: b [Reason:] i=40/2.

11. A pair of worm gear is written as 2/40/12/6. Calculate the pitch circle diameter of worm wheel.
a) 72mm
b) 240mm
c) 260mm
d) 320mm

View Answer

Answer: b [Reason:] d=mxz where m=6mm and z=40.

12. A pair of worm gear is written as 2/40/12/6. Calculate the throat diameter of the worm wheel.
a) 220.5mm
b) 246.4mm
c) 190.44mm
d) 251.7mm

View Answer

Answer: d [Reason:] d(t)=m[z+4cosϒ-2] where ϒ=9.46⁰ is the lead angle. tanϒ=2/12, z=40 and m=6mm.

13. A pair of worm gear is written as 2/40/12/6. Calculate the root diameter of the worm wheel.

a) 186.22mm
b) 250.4mm
c) 225.6mm
d) 250.44mm

View Answer

Answer: c [Reason:] d=m[z-2-0.4cosϒ] where ϒ=9.46⁰ is the lead angle. tanϒ=2/12, z=40 and m=6mm.

14. If tangential force on worm is 1500N, then axial force on worm wheel will be?
a) 1500N
b) 3000N
c) 1500√2 N
d) 750N

View Answer

Answer: a [Reason:] P₂(axial)=P₁(tangential).

Set 2

1. Which of the following is an unconventional process of machining?
a) Milling
b) AJM
c) Drilling
d) None of the mentioned

View Answer

Answer: b [Reason:] AJM stands for abrasive jet machining and it is an unconventional process of machining.

2. Abrasive jet machining process can be used for
a) Conductors
b) Insulators
c) Metals
d) All of the mentioned

View Answer

Answer: d [Reason:] Abrasive jet machining is more versatile and can be used for metal as well as non metal.

3. Which of the following is a conventional process of machining?
a) Electro chemical machining
b) Electron beam machining
c) Drilling
d) Abrasive jet machining

View Answer

Answer: c [Reason:] Drilling is a conventional process of machining.

4. For machining of plastic material which of the unconventional process can be used effectively?
a) Electro chemical machining
b) Electron beam machining
c) Abrasive jet machining
d) None of the mentioned

View Answer

Answer: c [Reason:] Abrasive jet machining is more versatile and can be used for metal as well as non metal.

5. Metal removal rate in abrasive jet machining increases with
a) Increase in abrasive flow rate
b) Decrease in abrasive flow rate
c) Decrease in grain size of abrasives
d) Increase in grain size of abrasives

View Answer

Answer: a [Reason:] Metal removal rate in abrasive jet machining increases with increase in abrasive flow rate. But after certain limit, erosion in nozzle become larger and velocity of grains become smaller.

6. Metal removal rate in abrasive jet machining increases with
a) Increase in abrasive flow rate but decreases beyond certain limit
b) Decrease in abrasive flow rate
c) Increase in grain size of abrasives
d) None of the mentioned

View Answer

Answer: a [Reason:] MRR is directly proportional to grain size.

7. Metal removal rate in abrasive jet machining increases with
a) Increase in standoff distance but decreases beyond certain limit
b) Decrease in abrasive flow rate
c) Decrease in grain size in grain size of abrasives
d) None of the mentioned

View Answer

Answer: a [Reason:] MRR is directly proportional to standoff distance up to certain limit. After certain limit, kinetic energy of abrasives starts decreasing.

8. Metal removal rate in abrasive jet machining increases with
a) Increase in gas pressure
b) Decrease in abrasive flow rate
c) Decrease in gas pressure
d) None of the mentioned

View Answer

Answer: a [Reason:] MRR is directly proportional to gas pressure.

9. Mixing ratio in abrasive jet machining is defined as ratio of
a) Mass flow rate of abrasive to mass flow rate of gas
b) Mass flow rate of gas to mass flow rate of abrasive
c) Velocity of gas to velocity of abrasive
d) None of the mentioned

View Answer

Answer: a [Reason:] Mixing ratio in abrasive jet machining is defined as ratio of mass flow rate of abrasive to mass flow rate of gas.

10. High abrasive flow rate decreases the life of nozzle in abrasive machining process.
a) True
b) False

View Answer

Answer: a [Reason:] Due to high velocity, erosion starts in nozzle which further decreases its life.

Set 3

1. Amount of time during which the transformer will be used for welding under normal loading condition is known as?
a) Hold time
b) Off time
c) Weld time
d) Duty cycle

View Answer

Answer: d [Reason:] Amount of time during which the transformer will be used for welding under normal loading condition is known as duty cycle.

2. Amount of voltage required to generate the arc under no load condition is called?
a) Open circuit voltage
b) Closed circuit voltage
c) Short circuit voltage
d) Arc voltage

View Answer

Answer: a [Reason:] Amount of voltage required to generate the arc under no load condition is called open circuit voltage.

3. Amount of current required to generate the arc under no load condition is called?
a) Open circuit current
b) Closed circuit current
c) Short circuit current
d) Arc current

View Answer

Answer: c [Reason:] Amount of current required to generate the arc under no load condition is called short circuit current. It is represented by SCC.

4. If the open circuit voltage is 60 volt and the short circuit current is 20 ampere. Then determine the voltage required for welding if the current required during welding is 10 ampere?
a) 30v
b) 60v
c) 20v
d) 40v

View Answer

Answer: a [Reason:] Voltage=OCV – (I/SCC) OCV, where OCV is open circuit voltage, SCC is short circuit voltage and I represents the current in amperes.

5. How does the arc voltage V depends upon the length of arc L?
a) V=f(L)
b) V=1/f(L)
c) V=f(L2)
d) V=f(√L)

View Answer

Answer: a [Reason:] V= A+BL. Voltage=OCV – (I/SCC) OCV, where OCV is open circuit voltage, SCC is short circuit voltage and I represents the current in amperes.

6. What is the function of flux in submerged arc welding?
a) To completely cover the welded zone
b) To prevent oxidation of joint
c) To prevent spattering of molten metal
d) All of the Mentioned

View Answer

Answer: d [Reason:] Flux is used to completely cover the welded zone, prevent oxidation of joint, prevent spattering of molten metal.

7. In which of the following gas welding process a non consumable electrode is used?
a) Submerged arc welding
b) Tungsten inert gas welding
c) Stud welding
d) Gas metal arc welding

View Answer

Answer: b [Reason:] In tungsten inert gas welding process a non consumable electrode is used. Electrode used is made of tungsten and filler metal is used addition to it.

8. What is the only difference between Plasma arc welding and TIG welding?
a) Flux is not used
b) Construction of torch is different
c) Gas is not used
d) None of the Mentioned

View Answer

Answer: b [Reason:] Construction of the torch is the only difference between Plasma arc welding and TIG welding. Both of the welding used tungsten electrodes.

9. In plasma arc welding the gas is?
a) Ionized
b) Heated
c) Magnetized
d) Vaporized

View Answer

Answer: a [Reason:] In plasma arc welding the gas is ionized. Electrode used is made of tungsten and filler metal is used addition to it.

10. If the heat transfer efficiency is 0.5 and the melting efficiency is 0.6, then the overall efficiency will be?
a) .83
b) .03
c) .30
d) .12

View Answer

Answer: c [Reason:] ηtotal=ηmelting*ηheat transfer, where η denotes efficiency. There are two types of efficiency generally use din welding, one is melting efficiency and other is heat transfer efficiency.

11. The deflection of the arc in arc blow is by?
a) Electric field
b) Magnetic field
c) Combination of both
d) Hydrostatic field

View Answer

Answer: b [Reason:] The deflection of the arc in arc blow is by magnetic field. Electric field, hydrostatic field does not effect the deflection of arc.

12. If the total efficiency is 0.35 in arc welding. Then what is the welding speed in mm/sec if the cross sectional area is 5mm2 , welding power is 2 kW and the heat required in melting the metal is 100 J/mm3.
a) 1.4
b) 14
c) 1400
d) 140

View Answer

Answer: a [Reason:] N = (P * total efficiency)/ (Q * A), where P represents power, q represents heat transfer, and A represents area.

13. Which of the following gas welding uses constant voltage welding?
a) Submerged arc welding
b) Tungsten inert gas welding
c) Stud welding
d) Gas metal arc welding

View Answer

Answer: d [Reason:] Gas metal arc welding uses constant voltage welding. Tungsten inert gas welding does not use constant circuit voltage.

14. Which of the following inert gas is used with DC power supply only?
a) Argon
b) Helium
c) CO2
d) All of the Mentioned

View Answer

Answer: c [Reason:] Co2 is used only in DC power supply. It cannot be used in AC power supply. Argon and helium can be used with AC supply.

15. In order to prevent oxidation and retain molten metal in stud welding which of the following is used?
a) Ceramic rings
b) Metal rings
c) Non metal rings
d) Flux

View Answer

Answer: a [Reason:] In order to prevent oxidation and retain molten metal in stud welding ceramic rings are used.

Set 4

1. Which of the following lathe requires very high skills for operation?
a) Centre lathe
b) Capstan lathe
c) Turret lathe
d) All of the mentioned

View Answer

Answer: a [Reason:] Centre lathe is much more typical than other lathe machines and hence requires much more skills.

2. Which of the following have lowest degree of automation?
a) Centre lathe
b) Capstan lathe
c) Turret lathe
d) All of the mentioned

View Answer

Answer: a [Reason:] Centre lathe has nominal degree of automation. Most of the operation are done manually and are not automatic.

3. Which of the following requires high labor cost?
a) Turret lathe
b) Capstan lathe
c) Centre lathe
d) All of the mentioned

View Answer

Answer: c [Reason:] Centre lathe requires high labor cost because it requires good skills for performing operations on it.

4. Which of the following offers minimum overhead charge?
a) Turret lathe
b) Capstan lathe
c) Centre lathe
d) All of the mentioned

View Answer

Answer: c [Reason:] Centre lathe requires low overhead charges due to small initial investment and low maintenance.

5. Which of the following lathe is most versatile?
a) Turret lathe
b) Capstan lathe
c) Centre lathe
d) All of the mentioned

View Answer

Answer: c [Reason:] Centre lathe is capable of handling varying shape jobs and hence is most versatile.

6. Turret head in turret lathe is generally mounted on
a) Slide
b) Saddle
c) Ram
d) None of the mentioned

View Answer

Answer: b [Reason:] Turret head is one of the important feature of turret lathe generally mounted on saddle.

7. Lead crew is present in turret lathe for thread cutting
a) True
b) False

View Answer

Answer: b [Reason:] Thread cutting in turret lathe is generally produced by taps and die heads, hence lead screw are not present in turret lathe.

8. Lead crew is present in Capstan lathe for thread cutting
a) True
b) False

View Answer

Answer: b [Reason:] Thread cutting in turret lathe is generally produced by taps and die heads, hence lead screw are not present in Capstan lathe.

9. Which of the following is not much effective for mass production i.e. production of same types of job?
a) Turret lathe
b) Capstan lathe
c) Centre lathe
d) All of the mentioned

View Answer

Answer: c [Reason:] Centre lathe have low degree of automation and is good in versatile jobs production.

10. Which of the following lathe requires low maintenance?
a) Turret lathe
b) Capstan lathe
c) Centre lathe
d) All of the mentioned

View Answer

Answer: c [Reason:] Turret and capstan have large number of parts, hence require large amount of maintenance.

Set 5

1. Which of the following defect is not a gas defect?
a) Blow holes
b) Air inclusions
c) Run out
d) Pin hole porosity

View Answer

Answer: c [Reason:] Run out is a moulding material defect. It is caused when molten metal leaks out of the mould. It may be caused due to faulty mould making.

2. Which gas defect is caused by hydrogen in molten metal?
a) Blow holes
b) Air inclusions
c) Open blows
d) Pin hole porosity

View Answer

Answer: d [Reason:] Pin hole porosity defect is caused by hydrogen in molten metal. This could have taken from furnace or due to dissociation of water molecules.

3. Cuts, washes, swell, drop etc. are the examples of which of the following casting defects?
a) Gas defect
b) Pouring material defect
c) Moulding material defect
d) Metallurgical defect

View Answer

Answer: c [Reason:] Cuts, washes, swell, drop etc. are the examples moulding material defect. These arises due to some defects in moulding material used for the casting process.

4. When the molten metal leaks out of mould which defect occurs?
a) Run out
b) Misrun
c) Fusion
d) Drop

View Answer

Answer: a [Reason:] Run out is a moulding material defect. It is caused when molten metal leaks out of the mould. It may be caused due to faulty mould making.

5. Which of the following defects are the examples of pouring material defects?
a) Misrun
b) Cold shut
c) Slag inclusion
d) All of the Mentioned

View Answer

Answer: d [Reason:] All the given defects are the examples of pouring material defect. Misrun occur when metal is unable to fill the mould cavity completely.

6. The lower fluidity of molten material causes
a) Misrun
b) Cold shut
c) Slag inclusion
d) Fusion

View Answer

Answer: b [Reason:] The lower fluidity of molten material causes cold shut defect. Fluidity in casting is used to designate the casting material ability to fill the mould cavity.

7. Defects caused by the chilling of the casting are known as
a) Hot spots
b) Hot tears
c) Shrinkage cavity
d) Swell

View Answer

Answer: a [Reason:] Defects caused by the chilling of the casting are known as hot spots. Proper metallurgical control and chilling practices are essential for eliminating such defects.

8. During melting process flux is added to react with impurities to form
a) Cavity
b) Slag
c) Cold shut
d) Blow holes

View Answer

Answer: b [Reason:] During melting process flux is added to react with impurities to form slag. If slag is not completely removed it may cause slag inclusions.

9. Which defect is caused due to the conversion of moisture to steam because of the heat of molten metal?
a) Open blows
b) Air inclusions
c) Blow holes
d) None of the Mentioned

View Answer

Answer: a [Reason:] Blow hole is caused due to the conversion of moisture to steam because of the heat of molten metal. Blow hole is a kind of gas defect.

10. Defect which occurs due to the solidification of casting is known as
a) Swell
b) Misrun
c) Metal penetration
d) Shrinkage cavity

View Answer

Answer: d [Reason:] Defect which occurs due to the solidification of casting is shrinkage cavity. Shrinkage cavity is a kind of gas defect.

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