Mechanical Engineering MCQs – Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) MCQs

Latest Mechanical Engineering MCQs

By practicing these MCQs of Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) MCQs – Latest Competitive MCQs , an individual for exams performs better than before. This post comprising of objective questions and answers related to “ Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) Mcqs “. As wise people believe “Perfect Practice make a Man Perfect”. It is therefore practice these mcqs of Mechanical Engineering to approach the success. Tab this page to check ” Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I )” for the preparation of competitive mcqs, FPSC mcqs, PPSC mcqs, SPSC mcqs, KPPSC mcqs, AJKPSC mcqs, BPSC mcqs, NTS mcqs, PTS mcqs, OTS mcqs, Atomic Energy mcqs, Pak Army mcqs, Pak Navy mcqs, CTS mcqs, ETEA mcqs and others.

Mechanical Engineering MCQs – Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) MCQs

The most occurred mcqs of ( ) in past papers. Past papers of Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) Mcqs. Past papers of Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) Mcqs. The Important series of Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) Mcqs are given below:

Metal Casting Fundamentals

1. ‘V’ or ‘f’ marked surfaces on a casting indicates?
a) Camber allowance
b) Machining allowance
c) Draft allowance
d) Shrinkage allowance
Answer: b
Explanation: Surfaces of castings required to be machined, are made to dimensions more than that indicated on the working drawings. The extra amount of material provided on the surfaces is called machine finish allowance and V or f is indicated on these surfaces.

2. Considering the shrinkage allowance, the amount of pattern, when compared to casting is?
a) larger than casting
b) smaller than casting
c) same as casting
d) equal to casting
Answer: a
Explanation: Shrinkage allowance is a correction for solidification shrinkage of metal and its contraction during cooling. It is larger than the casting to provide space for total contraction.

3. The process of removing unwanted material from the casting is called?
a) fettling
b) cleaning
c) finishing
d) blowing
Answer: a
Explanation: Fettling is the complete process of the cleaning of the casting. It involves removal o the cores, gates, risers, cleaning of the as surface and chipping of any of the unnecessary projection on the surfaces. Core can be removed simply by knocking of it with an iron bar or by means of a cone vibrator. Gates and risers can be removed by hammering, chipping, hack sawing, or by flame or arc cutting.

4. In the following type of foundry, melting unit, as well as balance equipment, are installed to the casting of the particular metal is?
a) jobbing foundry
b) ferrous foundry
c) mass production foundry
d) non-ferrous foundry
Answer: b
Explanation: A jobbing foundry is one that produces a casting or a small number of castings of a given kind as per order. Mass production foundries have automatic molding, pouring and finishing lines with a little or no manual handling. The melting unit, as well as balance equipment in the foundry, is installed in ferrous foundry to suit the casting of particular metal.

5. Which of the following is used for making the hollow cavities in the casting?
a) chaplet
b) vent rod
c) core
d) chill
Answer: c
Explanation: For producing a casting with internal cavities or passages, cores which are made of sand are utilized. Cores are placed in the mold cavity to form the interior surface of the casting and are removed from the finished part during fettling process.

6. What is the limitation of oil as a binder?
a) at lower temperature, bond between sand mix and oil becomes strong
b) at higher temperature, bond between sand mix and oil becomes strong
c) should be added in high volumes
d) quickly hardens
Answer: b
Explanation: At higher temperatures the bond between sand mix and oil becomes hard and brittle there by weakening the sand mix. So, care should be taken about the rate and temperature of baking of oil sands.

7. Cereals are added to the molding sand to improve which of the following?
a) hot strength
b) porosity
c) green strength
d) edge hardness
Answer: c
Explanation: The role of cereals on imparting an amount of green strength in oil sands has been mentioned. Cereals are used because they are less harmful than clays form the point of view of baked strength in oil sand cores. Starch is capable of imparting a higher green strength than dextrin for the same amount of moisture.

8. To improve the surface finish of castings, which of the following additive is used in the molding sand?
a) resins
b) sea coal
c) oils
d) wood flour
Answer: b
Explanation: Resins produces good bonding strength between the sand grains, oils are used as binders, wood flour is cellulose material used to overcome sand expansion defects and seal coal is finely ground soft coal used for surface finish of castings.

9. To permit the escape of gases generated in the mold, which of the following are provided?
a) vent holes
b) chills
c) chaplets
d) core print
Answer: a
Explanation: Chaplets are used to support the cores inside the mold cavity to take care of its own weight and overcome the metallostatic force, core print is used to create openings and various shaped cavities in the castings, and vent hole, a small opening in the mold to facilitate the escape of air and gases.

10. Which of the following is used for making the hollow cavities in the casting?
a) chaplet
b) vent rod
c) core
d) chill
Answer: c
Explanation: Chaplets are used to support the cores inside the mold cavity to take care of its own weight and overcome the metallostatic force, core is a separate part of the mold, made of sand and generally baked, which is used to create openings and various shaped cavities in the castings.

Metal Solidification and Fluid Flow

1. Grains created when a metal solidifies rather slowly in the presence of a steep temperature gradient fall in the category of?
a) equiaxed grains
b) columnar grains
c) elongated grains
d) planer grains
Answer: b
Explanation: Columnar grains are long, thin, coarse grains created when a metal solidifies rather slowly in the presence of a steep temperature gradient. Relatively few nuclei are available when columnar grains are produced.

2. Vacancies are _____________
a) planer defects
b) line defects
c) point defects
d) volume defects
Answer: c
Explanation: Vacancy defect is the simplest point defect. In this system, an atom is missing from its regular atomic site, vacancies are formed during solidification due to vibration of atoms.

3. Scanning tunneling microscope is a tool usually used to analyze an image at ____________
a) sub-atomic level
b) atomic level
c) micro level
d) macro level
Answer: b
Explanation: Scanning tunneling microscope (STM) is a technique that has been used for the surface study of nanostructures using the chemical composition of atoms and molecules in NPs to image surfaces at the atomic level. High-resolution material contrast has been successfully demonstrated in STM photon emission maps that correlate closely with the topographi image.

4. What are the examples of line defect?
a) vacancies
b) dislocations
c) twins
d) stacking faults
Answer: b
Explanation: Line imperfections, or dislocations, in crystalline solids are defects that cause lattice distortion centered around a line.

5. A mixture of a metal(s) and a non-metal(s) is called?
a) composite
b) alloy
c) dislocation
d) cermet
Answer: b
Explanation: A mixture of metal and non-metal is termed as an alloy, whereas a combination of two different materials (may not have metal in it) is called as composite.

6. If there are 930 grains per mm² on a photomicrograph of a metal at 2X, what is the ASTM grain size number of the metal?
a) 6
b) 7
c) 7.92
d) 8.91
Answer: d
Explanation: If there are 930 grains per mm² at 2X, then at 1X we will have
N^‘ = (2/1)² (930 grains/mm²) = 3720
therefore, N = N^‘/15.5 = 3720/15.5 = 240
240 = 2^n-2
log 240 = (n-1)(log 2)
2.380 = (n-1)(0.301)
n = 8.91.

7. An ASTM grain size determination is being made from a photomicrograph of a metal at a magnification of 1X. What is the ASTM grain size number of the metal if there are 992 grains per square mm?
a) 6
b) 7
c) 7.92
d) 8.91
Answer: b
Explanation: N = 2^n-1
where, N = no of grains per square inch at 100X
n = ASTM grain size number
and N is obtained using the following expression:
N = N^‘/15.5 where N^‘ = no. of grains per square mm at 1X
Thus, N = 992/15.5 = 64
or, 64 = 2^n-1
log 64 = (n-1)(log 2)
n = 7.

8. Risers are also called __________
a) spure
b) runners
c) feeders
d) risers
Answer: c
Explanation: Risers also called feeders serve as reservoirs of molten metal to supply any molten metal necessary to prevent porosity due to shrinkage during solidification.

9. In a free-falling liquid, the cross-sectional area of the stream?
a) increases
b) decreases
c) remains constant
d) first increases and then decreases
Answer: b
Explanation: In a free falling liquid, the cross sectional area of the stream decreases as the liquid gains velocity downward.

10. If the pouring basin has a much larger cross-sectional area than the sprue bottom, then the velocity of the molten metal is?
a) low
b) high
c) normal
d) either high or low
Answer: a
Explanation: The molten metal flows through a sprue to a runner and a gate and fills the mold cavity. If the pouring basin has a much larger cross sectional area than the sprue bottom, then the velocity of the molten metal at the top of the pouring basin is very low and can be taken to be zero.

Foundries Foundry Automation

1. Which of the following furnaces, are used extensively in foundries and have such advantages as a high rate of melting?
a) Induction
b) Electric arc
c) Crucible
d) Vacuum arc
Answer: b
Explanation: Electric-arc furnaces, are used extensively in foundries and have such advantages as a high rate of melting (and thus high-production rate), much less pollution than other types of furnaces, and the ability to hold the molten metal for alloying purposes.

2. Which of the following furnaces, are especially useful in smaller foundries?
a) Induction
b) Electric arc
c) Crucible
d) Vacuum arc
Answer: a
Explanation: Induction furnaces, are especially useful in smaller foundries and produce smaller Composition-controlled melts.

3. Which of the following furnace consists of a crucible completely surrounded with a water-cooled copper coil?
a) coreless induction
b) electric arc
c) channel
d) vacuum arc
Answer: a
Explanation: The coreless induction furnace consists of a crucible surrounded with a water-Cooled copper coil through which a high-frequency current pass. Because there is a strong electromagnetic stirring action during induction heating, this type of furnace has excellent mixing characteristics for alloying and adding a new charge of metal.

4. Which of the following furnaces uses a low-frequency current?
a) coreless induction
b) electric arc
c) channel
d) vacuum arc
Answer: c
Explanation: The channel furnace, uses a low-frequency Current (as low as 60 Hz) and has a coil that surrounds only a small portion of the unit.

5. Channel furnaces are used in?
a) superheating
b) holding
c) duplexing
d) all of the mentioned
Answer: d
Explanation: Channel furnace are used in nonferrous foundries and are particularly suitable for (a) superheating (that is, heating above normal Casting temperature to improve fluidity), (b) holding (which makes it suitable for die-casting applications), and (c) duplexing (using two furnaces-for instance, melt the metal in one furnace and transfer it to another).

6. Which of the following furnaces are heated with various fuels, such as commercial gases, fuel oil, and fossil fuel, as well as electricity?
a) Induction
b) Electric arc
c) Crucible
d) Vacuum arc
Answer: c
Explanation: Crucible furnaces, which have been used extensively throughout history, are heated with various fuels, such as commercial gases, fuel oil, and fossil fuel, as well as electricity. Crucible furnaces may be stationary, tilting, or movable.

7. Which of the following furnaces are basically vertical, refractory-lined steel vessels charged with alternating layers of metal, coke, and flux?
a) Cupolas
b) Electric arc
c) Crucible
d) Vacuum arc
Answer: a
Explanation: Cupolas are basically vertical, refractory-lined steel vessels charged with alternating layers of metal, coke, and flux. Although they require major investments and increasingly are being replaced by induction furnaces, cupolas operate continuously, have high melting rates, and produce large amounts of molten metal.

8. Which of the following technique involves magnetic suspension of the molten metal?
a) Cupolas
b) Levitation melting
c) Crucible
d) Induction melting
Answer: b
Explanation: Levitation melting involves magnetic suspension of the molten metal. An induction coil simultaneously heats a solid billet and stirs and confines the melt, thus eliminating the need for a crucible.

9. Which of the following is correct regarding “automation” in industry?
a) reduces the possibility of human error
b) minimizes labour cost
c) increases the production rate
d) all of the mentioned
Answer: d
Explanation: Automation minimizes labor, reduces the possibility of human error, increases the production rate, and attains higher quality levels.

10. Industrial robots are used in foundry operations for ___________
a) cleaning
b) riser cutting
c) mold venting
d) all of the mentioned
Answer: d
Explanation: Industrial robots are now used extensively in foundry operations, such as cleaning, riser cutting, mold venting, mold spraying, pouring, sorting, and inspection.

Heat Transfer-1

1. Rate of heat flow in conduction.
a) Is directly proportional to temperature gradient
b) Is inversely proportional to temperature gradient
c) Does not depend on temperature gradient
d) Does not depend on temperature gradient & inversely proportional to temperature gradient
Answer: a
Explanation: In conduction, heat transfer rate per unit area is proportional to a temperature gradient. Fourier’s law of conduction describes it as: q = -kA \(\frac{∂T}{∂x}\), where q = heat transfer rate, \(\frac{∂T}{∂x}\) = temperature gradient, k = thermal conductivity and the negative sign indicates heat flows downhill in temperature scale.

2. Thermal conductivity of silver in W/m-K is near about ___________
a) 210
b) 310
c) 410
d) 510
Answer: c
Explanation: Thermal conductivity of silver is nearly about 430 W/m-K at room temperature, for other materials, thermal conductivity values are tabulated below.

3. Thermal conductivity of copper in W/m-K is near about ___________
a) 210
b) 385
c) 485
d) 510
Answer: b
Explanation: Thermal conductivity of silver is nearly about 400 W/m-K at room temperature.

4. Thermal conductivity of aluminum in W/m-K is near about ___________
a) 202
b) 302
c) 410
d) 502
Answer: a
Explanation: Thermal conductivity of silver is nearly about 240 W/m-K at room temperature.

5. Which of the following is also known as transport property?
a) Pressure
b) Thermal conductivity
c) Resistance
d) Electrical conductivity
Answer: b
Explanation: Thermal conductivity of material is also known as transport property. It is an intrinsic property of a material which relates its ability to conduct heat. Heat transfer by conduction involves the transfer of energy within a material without any motion of the material as a whole.

6. With the use of thermal grease contact resistance will?
a) Increase
b) Decrease
c) Remains constant
d) First increases and then decreases
Answer: d
Explanation: Thermal grease reduces contact resistance. Silicon oil is thermal grease which decreases contact resistance.

7. Silicon oil applied between two contact surfaces will?
a) Increase contact resistance
b) Decrease contact resistance
c) Increase gap void
d) Does not depend upon contact resistance
Answer: b
Explanation: Silicone oil can act as a highly effective lubricant for sliding microelectromechanical system (MEMS) surfaces, increasing operational lifetime for devices with interacting surfaces, thus degrading electrical contact resistance.

8. When temperature of mercury liquid increases, its thermal conductivity?
a) Decreases
b) Increase
c) Remains constant
d) First increases and then decreases
Answer: a
Explanation: Thermal conductivity of liquid is inversely proportional to temperature. When temperature of mercury liquid increases, its thermal conductivity decreases.

9. When molecular weight of mercury liquid increases, its thermal conductivity?
a) Decreases
b) Increase
c) Remains constant
d) First increases and then decreases
Answer: a
Explanation: Molecular weight of liquid is inversely proportional to temperature. Thermal conductivity of liquid is inversely proportional to temperature.

10. Thermal conductivity of diamond is more than that of glass. It is because ___________
a) diamond has crystalline structure
b) glass has non crystalline structure
c) diamond and glass both have crystalline structure
d) diamond has amorphous structure
Answer: a
Explanation: Crystalline structures have more thermal conductivity due to lattice vibration. Thermal conductivity of liquid is inversely proportional to temperature.

Heat Transfer-2

1. Ratio of rate of heat conduction to the rate of internal energy storage is in solid is known as?
a) Biot number
b) Drag coefficient
c) Eckert number
d) Fourier number
Answer: d
Explanation: Fourier number is the ratio of heat conduction to the rate of heat storage. The significance of Fourier number is 1. It signifies the degree of penetration of heating or cooling effect, 2. It is a measure of heat conducted through a body relative to heat stored.

2. Ratio of pressure drop for internal flow through ducts is known as?
a) Friction factor
b) Grashof number
c) Colburn factor
d) Nusselt number
Answer: a
Explanation: Friction factor (µ) is defined as the ratio between the force required to move a section of pipe and the vertical contact force applied by the pipe on the seabed, in simpler terms, it is the ratio of pressure drop for internal flow though ducts.

3. Ratio of buoyancy to viscous forces is known as?
a) Prandtl number
b) Grashof number
c) Colburn factor
d) Nusselt number
Answer: b
Explanation: Grashof number in natural convection is analogous to the Reynolds number is forced convection. Grashof number indicates the ratio of the buoyancy force to the viscous force. Higher Gr number means increased natural convection flow.

4. Which of the following is known as the dimensionless heat transfer coefficient?
a) Friction factor
b) Grashof number
c) Colburn factor
d) Weber number
Answer: c
Explanation: Colburn factor obtained from the Reynold-Colburn analogy relates to the local skin friction coefficient (from fluid mechanics) to the local convective heat transfer coefficient.

5. Which of the following is known as the dimensionless heat transfer coefficient?
a) Friction factor
b) Grashof number
c) Nusselt number
d) Prandtl number
Answer: c
Explanation: Nusselt number is a dimensionless number and it is defined as the ratio of convective heat flux to the conductive heat flux (where fluid is in rest). Convection in fluid = conduction in fluid + advection in fluid (occurs due to motion of fluid). So, practically we can understand it as a comparison of heat taken by fluid due to moving fluid and heat taken by a static fluid when flowing over a heated plate (or inside a pipe).

6. Ratio of convection heat transfer to conduction is known as?
a) Friction factor
b) Grashof number
c) Colburn factor
d) Nusselt number
Answer: a
Explanation: The Nusselt number is the ratio of convective to conductive heat transfer across a boundary.
Nu = \(\frac{hl}{k}\), where, h = heat transfer coefficient, l = characteristic length and k = thermal conductivity.

7. Product of Prandtl number and Reynolds number is also known as?
a) Peclet number
b) Prandtl number
c) Rayleigh number
d) Biot number
Answer: a
Explanation: Peclet number is the product of Prandtl number and Reynolds number, in other sense, it is the ratio of the heat transfer by convection to the heat transferred by conduction. So, you can consider a pipe with some wall thickness. The wall conducts heat to the fluid. While the heat can also be carried away by the fluid in motion which is called as advection. If the advection term is dominant, then the Peclet number is going to large and thus the hat transfer from the wall is of less importance. Conversely, the heat transfer form the wall to the fluid can be of higher importance in the case of a smaller Peclet number.

8. Ratio of molecular diffusivity to thermal diffusivity is also known as?
a) Biot number
b) Prandtl number
c) Rayleigh number
d) Biot number
Answer: b
Explanation: Prandtl number as explained by others here, is a dimensionless number, which is the ratio of molecular diffusivity of momentum to molecular diffusivity of heat. It shows the relative thickness of the velocity boundary layer to the thermal boundary layer.

9. Product of Grashof and Prandtl is known as?
a) Peclet number
b) Biot number
c) Rayleigh number
d) Reynolds number
Answer: c
Explanation: Rayleigh number is the product of Grashof and Prandtl number.

10. Ratio of inertia to viscous forces is known as?
a) Stanton number
b) Prandtl number
c) Rayleigh number
d) Reynolds number
Answer: d
Explanation: The Reynolds number is the ratio of inertial forces to viscous forces. The Reynolds number is a dimensionless number used to categorize the fluids systems in which the effect of viscosity is important in controlling the velocities or the flow pattern of a fluid.

Fluid Flow and Heat Transfer

1. The flow of fluid which is highly chaotic is called as?
a) Laminar
b) Turbulence
c) Reynolds
d) Irrotational flow
Answer: b
Explanation: Turbulent flow is chaotic. However, not all chaotic flows are turbulent. Turbulent flow is characterized by the irregular movement of particles of the fluid. In contrast to laminar the fluid does not flow in parallel layers, the lateral mixing is very high, and there is a disruption between the layers. Turbulence is also characterized by recirculation, eddies, and apparent randomness, in other sense, in turbulent flow-the speed of the fluid at a point is continuously undergoing changes in both magnitude and direction.

2. The capability of molten metal to fill mold cavities is called ____________
a) viscosity
b) fluidity
c) turbulence
d) velocity
Answer: b
Explanation: Fluidity is the property of a fluid which allows fluid to flow. In general understanding, one can say, the fluidity is inversely proportional to viscosity. Factors affecting fluidity in casting are as follows.
i. Modulus: fluidity length increases as the modulus (volume/surface area) of the casting increases
ii. Section thickness: larger thickness of section results in higher fluidity
iii. Heat transfer coefficient: a reduction in the rate of heat transfer will increase fluidity
iv. Superheating: the temperature increment above the melting point increases fluidity
v. Mould temperature: higher mould temperature increases fluidity
vi. Pouring rate: lower pouring rates decrease fluidity because of larger cooling.

3. The liquid metal reduces its fluidity mainly due to?
a) high viscosity
b) high friction factor
c) high surface tension
d) high turbulence
Answer: c
Explanation: A high surface tension of the liquid metal reduces fluidity. Because of this, oxide films on the surface of the molten metal have a significant adverse effect on fluidity.

4. The slower the rate of pouring molten metal into the mold, the nature of fluidity will be?
a) lower
b) higher
c) constant
d) either higher or lower
Answer: a
Explanation: The slower the rate of pouring molten metal into the mold, the lower is the fluidity because of the higher rate of cooling when poured slowly.

5. With an increase in the thickness of insulation around a circular pipe, heat loss to surrounding due to ____________
a) convection increase, while that the due to conduction decreases
b) convection decrease, while that due to conduction increases
c) convection and conduction decreases
d) convection and conduction increases
Answer: b
Explanation: By increasing the thickness of insulation, the convection heat transfer co-efficient decreases and heat loss by the convection also decreases. These both cases are limited for the critical thickness of insulation.

6. For a given heat flow and for the same thickness, the temperature drop across the material will be maximum for ____________
a) copper
b) steel
c) glass-wool
d) refractory brick
Answer: c
Explanation: Q = -kA (dT/dx)
Qdx/A = -kdT
therefore, kdT = constant or dT ∞ 1/k.

7. In descending order of magnitude, the thermal conductivity of:
i. Pure iron,
ii. Liquid water,
iii. Saturated water vapour, and
iv. Pure aluminium
can be arranged as?
a) (i), (ii), (iii) and (iv)
b) (ii), (iii), (i) and (iv)
c) (iv), (i), (ii) and (iii)
d) (iv), (iii), (ii) and (i)
Answer: c
Explanation: Thermal conductivity of values at room temperature are tabulated below:

8. A copper block and an air mass block having similar dimensions are subjected to symmetrical heat transfer from one face of each block. The other face of the block will be reaching the same temperature at a rate is?
a) Faster in air block
b) Faster in copper block
c) Equal in air as well as copper block
d) Cannot be predicted with the given information
Answer: b
Explanation: Copper has a thermal conductivity of 400 W/m-K and air has an value of 0.026 W/m-K.

9. Consider the following statements:
The Fourier heat conduction equation Q = -kA(dT/dx) presumes
i. Steady-state conditions
ii. Constant value of thermal conductivity.
iii. Uniform temperatures at the wall surfaces
iv. One-dimensional heat flow.
Which of the above statements are correct?
a) (i), (ii) and (iii) are correct
b) (i), (ii) and (iv) are correct
c) (ii), (iii) and (iv) are correct
d) (i), (iii) and (iv) are correct
Answer: d
Explanation: Thermal conductivity may constant or variable.

10. The outer surface of a long cylinder is maintained at constant temperature. The cylinder does not have any heat source. The temperature in the cylinder will?
a) Increase linearly with radius
b) Decrease linearly with radius
c) Be independent of radius
d) Vary logarithmically with radius
Answer: d
Explanation: In case of cylinder, in Q = -kA (dT/dr), thus indicating the logarithmic change.

11. For conduction through a spherical wall with constant thermal conductivity and with inner side temperature greater than outer wall temperature, (one dimensional heat transfer), what is the type of temperature distribution?
a) Linear
b) Parabolic
c) Hyperbolic
d) Logarithmic
Answer: c
Explanation: Temp distribution would be t – t_1.

Mechanical Engineering MCQs – Forming, Metal Forming Processes And Heat Transfer ( Manufacturing Engineering – I ) MCQs