Category: Manufacturing Engineering Objective Questions

Manufacturing Engineering Multiple Choice Questions on “Magnetic Properties of Material”.

1. Which of the following parameter is used to assess the magnetic ability of a material?
a) Magnetic flux density
b) Magnetization
c) Magnetic dipole moment
d) Susceptibility
Answer: d
Clarification: Magnetic susceptibility is a measure to quantify the ability of a material to undergo magnetization in an applied magnetic field. It is the ratio of magnetization (M) to the applied magnetic field intensity (H).

2. For a diamagnetic material, which of the following statement is correct?
a) Magnetic susceptibility < 0
b) Magnetic susceptibility > 0
c) Magnetic susceptibility = 0
d) Magnetic susceptibility = 1
Answer: a
Clarification: Diamagnetic materials are those which repel magnetic field and hence their magnetic susceptibility (χ) is negative.

3. For a diamagnetic material, which of the following statement is correct (μ_r = relative permeability)?
a) μ_r > 2
b) μ_r < 1
c) μ_r > 1
d) μ_r = 1
Answer: b
Clarification: A diamagnetic material has a constant relative permeability (μ_r) slightly less than 1.

4. For a paramagnetic material, which of the following statement is correct?
a) Magnetic susceptibility < 0
b) Magnetic susceptibility > 0
c) Magnetic susceptibility = 0
d) Magnetic susceptibility = -1
Answer: b
Clarification: Magnetic susceptibility (χ) is very small positive quantity for a paramagnetic material.

5. For a paramagnetic material, which of the following statement is correct (μ_r = relative permeability)?
a) μ_r = 0
b) μ_r < 1
c) μ_r > 1
d) μ_r < 0
Answer: c
Clarification: A paramagnetic material has a constant relative permeability (μr) slightly greater than 1.

6. What is the curie temperature of iron (in kelvin scale)?
a) 2195 K
b) 495 K
c) 895 K
d) 1095 K
Answer: d
Clarification: The curie temperature of iron is about 1095K. It changes its magnetic behaviour from ferromagnetic to paramagnetic.

7. With an increase in temperature, magnetic susceptibility of a ferromagnetic material ____________
a) Increases
b) Decreases
c) Remains constant
d) First increases and then decreases
Answer: a
Clarification: Magnetic susceptibility of a ferromagnetic material decreases with increase in temeprature.

8. With an increase in temperature, magnetic susceptibility of an anti-ferromagnetic material ____________
a) Increases
b) Decreases
c) First decreases and then increases
d) First increases and then decreases
Answer: d
Clarification: Susceptibility of an anti-ferromagnetic material is first increases and then decreases with increase in temperature.

9. With an increase in the area of hysteresis curve, power loss will ___________
a) Increases
b) Decreases
c) First decreases and then increases
d) First increases and then decreases
Answer: a
Clarification: Power loss is directly proportional to the area of hysteresis curve.

10. Magnetic Bubbles are used as __________
a) Storage device
b) Strain gauge
c) Thermostat
d) Potentiometer
Answer: a
Clarification: Magnetic bubbles are small magnetized areas used as storage devices (data bites). One good thing about magnetic bubbles are they do not disappear when power is turned off.

Manufacturing Engineering Multiple Choice Questions on “Machinability”.

1. The specific cutting energy used for establishing the machinability of the metal depends upon its
a) coefficient of friction
b) micro-structure
c) work hardening characteristics
d) all of the mentioned
Answer: d
Clarification: None

2. For machining a mild steel workpiece using carbide tool, the maximum material will be removed at a temperature of
a) 50⁰
b) 100⁰
c) 175⁰
d) 275⁰
Answer: b
Clarification: None

3. For machining a mild steel workpiece by a high speed steel tool, the average cutting speed is
a) 5 m/min
b) 10 m/ min
c) 15 m/min
d) 30 m/min
Answer: d
Clarification: For machining a cast iron workpiece by a high speed steel tool, the average cutting speed is 22 m/min and for a mild steel is 30 m/min.

4. For machining a cast iron workpiece by a high speed steel tool, the average cutting speed is
a) 10 m/min
b) 15 m/min
c) 22 m/min
d) 30 m/min
Answer: c
Clarification: For machining a cast iron workpiece by a high speed steel tool, the average cutting speed is 22 m/min and for a mild steel is 30 m/min.

5. The machining of titanium is difficult due to
a) high thermal conductivity of titanium
b) chemical reaction between tool and work
c) low tool-chip contact area
d) none of the mentioned
Answer: c
Clarification: None

6. The factor considered for evaluation of maintainability is
a) cutting forces and power consumption
b) tool life
c) type of chips and shear angle
d) all of the mentioned
Answer: d
Clarification: None

7. In machining metals, chips break due to _____________ of work material.
a) toughness
b) ductility
c) elasticity
d) work hardening
Answer: d
Clarification: None

8. In machining metals, surface roughness is due to
a) feed marks or ridges left by the cutting tool
b) fragment of built up edge on the machined surface
c) cutting tool vibrations
d) all of the mentioned
Answer: d
Clarification: None

9. In machining soft materials, a tool with a negative relief angle is used
a) True
b) False
Answer: a
Clarification: None

10. The tool material, for faster machining, should have
a) wear resistance
b) red hardness
c) toughness
d) all of the mentioned
Answer: d
Clarification: None

Manufacturing Engineering Question Bank on “Milling Operations”.

1. Diameter of milling cutter is 100 mm, running at 210 rpm. Cutting speed in m/min is equal to
a) 26
b) 23
c) 66
d) 78
Answer: c
Clarification: V= (3.14*D*N)/1000. V is the cutting speed, D is diameter and N is the revolution per minute.

2. Distance moved by table in mm in one minute in any direction is known as
a) Feed per minute
b) Feed per tooth
c) Feed per revolution
d) None of the mentioned
Answer: a
Clarification: Distance moved by table in mm in one minute in any direction is known as feed per minute.

3. Distance moved by a table in mm during time when cutter revolve through angle corresponding to distance between two cutting edges of two adjacent teeth is known as
a) Feed per minute
b) Feed per tooth
c) Feed per revolution
d) None of the mentioned
Answer: b
Clarification: Distance moved by a table in mm during time when cutter revolves through angle corresponding to distance between two cutting edges of two adjacent teeth is known as feed per tooth.

4. In a milling operation, feed per tooth is 0.020 mm and the total number of teeth on milling cutter is 50. Feed per revolution in mm is equal to
a) 0.2
b) 1.4
c) 1.0
d) 0.7
Answer: c
Clarification: Feed per revolution= feed per tooth * number of teeth.

5. In a milling operation, feed per revolution is 5 mm and the total number of teeth on milling cutter is 50. Feed per tooth in mm is equal to
a) 0.1
b) 0.2
c) 0.5
d) 0.05
Answer: a
Clarification: Feed per revolution= feed per tooth * number of teeth.

6. In a milling operation, feed per revolution is 0.05 mm and speed of 400 rpm. Feed per min in mm/min is equal to
a) 1
b) 2
c) 0.5
d) 0.05
Answer: b
Clarification: Feed per minute= feed per revolution* speed.

7. In a milling operation, feed per min is 10 mm and speed of 500 rpm. Feed per min in mm/min is equal to
a) 1
b) 2
c) 0.5
d) 0.04
Answer: d
Clarification: Feed per minute= feed per revolution* speed.

8. In a milling operation feed per tooth is .002 mm and number of teeth is 50 rotating with 60 rpm. Feed per min in mm/min is equal to
a) 3
b) 4
c) 6
d) None of the mentioned
Answer: c
Clarification: Feed per minute= feed per tooth* speed*number of teeth.

9. In a milling operation feed per tooth is .002 mm and number of teeth is 30 rotating with 40 rpm. Feed per min in mm/min is equal to
a) 3
b) 4.3
c) 2.4
d) None of the mentioned
Answer: c
Clarification: Feed per minute= feed per tooth* speed*number of teeth.

10. In a milling operation feed per revolution is 10 mm/rev and number of teeth is 50 rotating with 10 rpm. Feed per tooth in mm is equal to
a) .02
b) .04
c) .06
d) None of the mentioned
Answer: a
Clarification: Feed per minute= feed per tooth* speed*number of teeth.

To practice Manufacturing Engineering Question Bank,

Manufacturing Engineering Multiple Choice Questions on “Electrochemical Machining”.

1. Which of the following is un-conventional machining process?
a) Grinding
b) Milling
c) Turning
d) Electro chemical machining
Answer: d
Clarification: Electro chemical machining is an un-conventional machining process used for large material removal from the surface using electricity generated due to chemical reactions.

2. Which of the following is conventional machining process?
a) Electro chemical machining
b) Milling
c) Electron discharge machining
d) None of the mentioned
Answer: b
Clarification: Milling is a conventional machining process used for material removal from the surface.

3. In ECM, heavy electrical sparks are created.
a) True
b) False
Answer: b
Clarification: Sparks are generated in EDM, by using high voltage current, for proper erosion of material.

4. In ECM, tool does not touch the work piece.
a) True
b) False
Answer: a
Clarification: Tool is very near to work piece but does not touch it in ECM.

5. Which of the following is correct about ECM?
a) Erosion of metal takes place as a reverse process of electroplating
b) Thermal stresses are induced
c) Mechanical stresses are induced
d) None of the mentioned
Answer: a
Clarification: In ECM, erosion of metal takes place as reverse process of electroplating.

6. Which of the following material cannot be machined using electro chemical machining?
a) Iron
b) Aluminum
c) Copper
d) Wood
Answer: d
Clarification: Wood is a bad conductor of electricity and hence cannot be machined using electro chemical machining.

7. Which of the following material can be machined using electro chemical machining?
a) Iron
b) Rubber
c) Plastic
d) Wood
Answer: a
Clarification: Iron is a good conductor of electricity and hence can be machined using electro chemical machining.

8. Electrode gap in electro chemical machining is generally ranged from
a) 0.5 mm to 0.9 mm
b) 1.1 mm to 1.2 mm
c) 0.1 mm to 0.2 mm
d) 3.1 mm to 4.2 mm
Answer: c
Clarification: Electrode gap in electro chemical machining is generally ranged from 0.1 mm to 0.2 mm.

9. Electrolytes used in ECM must posses
a) Low electrical conductivity
b) Low chemical stability
c) High electrical conductivity
d) None of the mentioned
Answer: c
Clarification: Electrolytes used in ECM must have high electrical conductivity.

10. Which of the following is not a function of electrolyte in ECM?
a) It completes the circuit
b) It helps in electrochemical reaction
c) It carries away heat and waste product
d) It provide non reactive environment
Answer: d
Clarification: Electrolyte provides reactive environment for chemical reactions to takes place.

Manufacturing Engineering Multiple Choice Questions on “Unconventional Welding Methods”.

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: a
Clarification: In percussion welding, two pieces are welded by a high intensity short duration arc followed by very rapid or percussive impacting of the workpieces. There are three different methods of arc initiation in percussion welding viz., low voltage with drawn arc, high voltage breakdown, and ionising by a fusing tip. With each method, the energy source is a bank of capacitors which is charged by a variable voltage transformer cum rectifier unit.

2. In which welding process pressure is applied by detonating a layer of explosive?
a) Percussion welding
b) Explosion welding
c) Diffusion welding
d) Thermit welding
Answer: b
Clarification: In explosion welding, a compression force created by detonation of explosives is used to join overlapping metal sheets. The joining parts are arranged toward each other at an angle of 1-15°, depending on the material and method, and are prepared with a layer of explosive on the top.

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: d
Clarification: In ultrasonic welding (USW), the faying surfaces of the two members are subjected to a static normal force and oscillating shearing (tangential) stresses. The shearing stresses are applied by the tip of a transducer similar to that used for ultrasonic machining.

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: a
Clarification: In diffusion welding, the bond strength is achieved by pressure, temperature, time of contact, and cleanness of the surfaces. The strength of the bond is primarily due to diffusion rather than any plastic deformation.

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: d
Clarification: Thermite welding is a welding process in which the workpiece is joined with the help of molten metal by means of an exothermic reaction. Thermite mixture consists of a metal oxide (usually iron oxide) and aluminum powder. The major application of thermite welding is to weld railway tracks. It is also used to weld heavy machinery.

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: b
Clarification: Atomic hydrogen welding, also known as AHW, is an arc welding technique that uses an arc which is located between two tungsten electrodes and a hydrogen shielding gas.

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: d
Clarification: Electro gas welding (EGW) is an vertical positioned arc welding process, is used for welding the edges of sections vertically and in one pass with the pieces placed edge to edge (butt joint).

8. Electron beam welding is carried in?
a) Inert atmosphere
b) Partially filled chamber
c) Vacuum
d) Partially vacuum
Answer: c
Clarification: In electron beam welding process, electrons are emitted from the heated filament called electrode. This is done under vacuum conditions to prevent dissipation of the electron beam.

9. Which of the following welding process the weld joint is obtained by means of filler material and not by melting?
a) Diffusion welding
b) Thermit welding
c) Electroslag welding
d) Brazing
Answer: d
Clarification: A brazed joint is made in a completely different manner from welded joint. The big difference is in temperature-brazing does not melt the base metals. This means that brazing temperatures are invariably lower than the melting points of the base metals. It joins base metals by creating a metallurgical bond between the filler metal and the surfaces of the two metals being joined. The principle by which the filler metal is drawn through the joint to create this bond is capillary action.

10. Which of the following statements is not true?
a) Brazing occurs at a temperature above 450°C
b) Soldering occurs at a temperature below 450°C
c) Epoxy resins are used to join metals, ceramics etc
d) Epoxy resins are not used to join metals, ceramics etc
Answer: d
Clarification: The excellent adhesive properties of epoxy resins are due to the attractive forces between the epoxy resin and the surface of the substrate. Typical epoxy resins have pendant hydroxyl (-OH) groups along their chain which can form bonds or strong polar attractions to oxide or hydroxyl surfaces. Most inorganic surface, i.e., metals, minerals, glasses, ceramics, etc. have polarity so they have high surface energy. Organic polymer surfaces are generally less polar (more covalent) thus lower surface energy.

Manufacturing Engineering Multiple Choice Questions on “Forming”.

1. Depending upon the temperature the forming process can be classified as?
a) Hot working
b) Cold working
c) Warm working
d) All of the mentioned
Answer: d
Clarification: Depending upon the temperature the forming process can be classified as hot working, cold working, and warm working.

2. If T_m is the melting temperature, then in hot working the value for that material is?
a) 0.5 T_m
b) 0.6 T_m
c) 0.4 T_m
d) 0.7 T_m
Answer: b
Clarification: If T_m is the melting temperature then in hot working the value of T_m is .6 T_m. Hot working is done above recrystallization temperature.

3. In which of the following process no strain hardening is produced?
a) Hot working
b) Cold working
c) Warm working
d) Cannot say
Answer: a
Clarification: In hot working (working above recrystallization temperature), no strain hardening is produced, this is because, when hot working is done, there is simultaneous recrystallization and grain growth due to elevated temperature. So, the material regains its ductility and there is no residual stress in the material.

4. During hot working, the grain growth can take place in which part of the material?
a) Exterior
b) Interior
c) Along the edges
d) Side faces
Answer: b
Clarification: During hot working, the grain growth can take place in the interior part of the material because the interior part cools slowly the remaining parts.

5. Which of the following defect is eliminated by hot working process?
a) Cold shut
b) Misrun
c) Blow holes
d) Fusion
Answer: c
Clarification: Blow holes and porosities can be eliminated at high temperature, thus in hot working process.

6. The working temperature of cold working is below a certain temperature. That temperature is known as?
a) Critical temperature
b) Recrystallization temperature
c) Transition temperature
d) Curie temperature
Answer: b
Clarification: Recrystallization temperature is generally defined as temeprature at which complete recrystallization occurs within approximately one hour, in other sense, recrystallization temperature of a given metal is about one-half its melting point (0.5 Tm) as measured on an absolute temperature scale.

7. In which of the following process the ductility of material decreases?
a) Hot working
b) Cold working
c) Warm working
d) Cannot say
Answer: b
Clarification: Cold working is the work done below recrystallization temperature. As cold work is increased, yield strength and tensile strength increases, percentage of ductility decreases.

8. Which of the following statement is true about cold working?
a) Strain hardening is relieved
b) No oxidation occurs
c) Only limited amount of reduction can be done
d) Cost of machining is high
Answer: a
Clarification: A comparison of hot and cold working are tabulated below:

S.No.	Hot Working	Cold Working
1.	Working above recrystallization temperature	Working below recrystallization temperature
2.	Formation of new crystals (grains)	No crystal formation
3.	Surface finish is not good	Surface finish is good
4.	No stress formation	Internal stress developed
5.	Improved mechanical property due to grain formation	Leads to distortion of metal grains
6.	Closed dimensional tolerances cannot be maintained	Superior dimensions can be obtained
7.	Improves some mechanical properties like, impact strength and elongation	During process, strength and elongation decreases