Mechanical Engineering Multiple Choice Questions
Our top 50 Mechanical Engineering questions and answers focus on all the areas of this subject. It covers over more than 50 topics in Mechanical Engineering. Anyone who wishes to sharpen their knowledge, preparing for the interviews, or preparing for the entrance exam can practice these Mechanical Engineering Questions.
1) What we call the resistance of a material against any external force.
Answer: D [ Strength ]
Description: Strength is a mechanical property of the material under which it resists change in its dimension shape and any failure by applying any external force.
2) Which hardness test uses the steel ball as indenter?
Answer: B [ Brinell Hardness Test ]
Description: Steel ball is used as an indentor in the Brinell hardness test.
3) In which test, the specimen will be used in the form of the supported beam?
Answer: C [ Izod Test ]
Description: Izod test is like the Charpy test, but the Izod geometry consists of a cantilever beam with the notch located on the same side as the impact point.
4) Which metal from the following has the non-crystalline structure?
Answer: B [ Silica Glass ]
Description: Generally, metals exist in crystalline form. The ceramic compound-silica (SiO2), can exist either in a crystalline form or in a non-crystalline form (amorphous form). Silica's non-crystalline (amorphous) form is just called silica glass.
5) Which of the following has less crystallinity?
Answer: C [Low-Density Polythene ]
Description: Iron and nickel, metals, possess a crystalline form, whereas high-density polyethylene (HDPE) and low-density ethylene (LDPE) are a class of polymers. These thermoplastics are semi-crystalline, out of which LDPE exhibits a crystallinity of about 50-60% and HDPE of about 90%. Some people may term HDPE as crystalline, but it is more appropriate to restrict it in the category of semi-crystalline class.
6) Which of the following axis system is being satisfied by tetragonal crystal system?
Answer: B [a = b ≠ c, α = β = ϒ = 90°]
Description: Tetragon has two sides equal and all angles equal
7) Which one of the following is least symmetrical?
Answer: C [ Triclinic ]
Description: In the triclinic crystal system, we observe all the sides and angles to be unequal (a ≠ b ≠ c and α ≠ β ≠ γ ≠ 90°), thus giving the least symmetry (1-fold symmetry) among all 7 Bravais Lattices.
8) ASTM stands for?
Answer: A [ American Society for Testing and Materials ]
Description: ASTM stands for American Society for Testing and Materials. ASTM develops technical standards for a wide range of materials products. American Society for Tensile Measurement is used to decide various standards in tensile measurement.
9) What is the scale range of the Mohs hardness test?
Answer: A [ 1- 10 ]
Description: Mohs hardness scale was developed by "Frederich Mohs" in 1822, a chart that denotes the various materials' relative hardness (1-softest to 10-hardest). According to the Mohs scale, diamond is the hardest material, and talc is the softest material.
10) What is the first step involved in the process of preparing test samples for microstructural examination?
Answer: A [ Fine grinding ]
Description: Fine grinding involves using abrasive silicon carbide to get a flat surface, i.e., nearly free of the disturbed or deformed scratches introduced in the previous sample preparation step.
11) Etching of specimen is done to achieve _______
Answer: B [ Visible Grain Boundary ]
Description: Etching is done to obtain a visible grain boundary. It is a surface treatment process.
12) Which equipment can be used for the inspection of the inside portion of the hollow chamber or narrow tube?
Answer: D [ Borescope ]
Description: A borescope is used for visual of the inside portion of the hollow chamber.
13) Which of the following property is the fine-grained structure?
Answer: B [ Ductility ]
Description: Finer the grain size (lower the grain size), more is the number of grain boundaries. Thus more is the yield strength; thus, more is the flexibility. This is the reason why we can easily draw a fine-grained structure into wires.
14) Which penetrating liquid is used for the liquid penetration test?
Answer: B [ Petroleum-based carrier fluid ]
Description: In a liquid penetration test, either petroleum-or-water-based carrier fluids are used as solvents or cleaners according to the type of penetrant used. The petroleum-based carrier fluid is a penetrating liquid in a liquid penetration test and fluorescent red color dye for visible light.
15) Which of the following non-destructive testing is used to detect the change in the composition of any material?
Answer: C [ Radiography ]
Description: It enables us to detect the change in composition. X-rays or γ-rays are used in radiography techniques.
16) What is the melting point of iron (in ℃)?
Answer: A [ 1535 ]
Description: The melting point of iron in degree centigrade is 1535℃.
17) What is the Iron-Carbon phase diagram?
Answer: B [ Binary phase diagram ]
Description: Binary phase diagrams are based on two-component systems. Here, the two components may be mixed in an infinite number of different proportions, which indicates that composition also becomes a variable, along with pressure and temperature. The iron-carbon phase diagram, Pb-Sn diagram are the best examples of this category.
18) Which of the following reaction does not exhibit a mushy zone in the Fe-C phase diagram?
Answer: B [ Eutectic ]
Description: A mushy zone is nothing but a solid-liquid mix in a two-phase region. The alloys or reactions, which exhibit lower melting points than the two pure metals, are known as eutectic alloy systems taking eutectic reactions that do not exhibit mushy zone.
19) Which of the following material has the carbon varying from 2.1 to 4.3%?
Answer: C [ Cast-Iron ]
Description: Cast irons are the alloy of iron and carbon that contains 2.1 to 4.3% C, along with other varying amounts of silicon and manganese. This varying carbon range makes them easily castable, asking them to call cast irons.
20) Which of the following material has the carbon varying from 4.3 to 6.67%?
Answer: B [ Pig Iron ]
Description: Pig iron contains a very high carbon content, usually varies from 4.3 to 6.67%. The pig iron is called so, as it resembles the shape of a reclining pig.
21) Which equation represents the Gibbs phase rule?
Answer: A [ F = C - P + 2 ]
Description: The Gibbs phase rule is represented as F = C - P + 2, where F = number of intensive degrees of freedom, P = number of phases, and C = the minimum number of independent constituents.
22) The invariant reaction involving a liquid phase decomposing into two different solids on cooling is known as _____
Answer: A [ Eutectic point ]
Description: Explanation: The eutectic invariant reaction, in general, can be represented as:
L → S1 + S2
L represents the liquid of eutectic composition, and S1 and S2 are two different solids of fixed composition each.
23) The Line joining a liquid phase with liquid and solid phase mixture is known as ________
Answer: B [ Liquidus ]
Description: Liquidus is the line joining liquid phase with liquid and solid phase mixture.
24) The line joining a solid phase with liquid and solid phase mixture is known as ________
Answer: A [ Solidus ]
Description: Solidus is the line joining liquid phase with liquid and solid phase mixture.
25) Cast iron is a product of _______
Answer: B [ Cupola ]
Description: The cupola furnace (a modified blast furnace) can melt cast irons, bronzes, etc. Cast irons have a carbon content of 2-4% and have low melting temperatures, making them easily castable.
26) Wrought iron is a product of ______
Answer: C [ Puddling furnace ]
Description: The puddling furnace creates wrought iron (nearly pure iron) from the pig iron. The wrought iron is tougher and malleable.
27) Which of the following induces fine-grain distribution in alloy steel?
Answer: A [ Vanadium ]
Description: Vanadium is the most used grain refiner in steel. It forms a microscopic precipitate particle in steel, which acts as pinning agents, thus obstruct grain growth at higher temperatures, encouraging new grains to nucleate.
28) Tensile strength of alloy steel can be improved by adding ______
Answer: B [ Nickel ]
Description: Nickel can improve tensile strength as well as the toughness of alloy steel. Small additions of niobium (Nb) also increases the tensile strength of carbon steel.
29) Which of the following is the hardest constituent of steel?
Answer: C [ Martensite ]
Description: Martensite is the hardest constituent of steel. The primary reasons for the internal strains within BCC iron are the excess of carbon and the plastic deformation of parent FCC iron surrounding the martensitic plate. The cooling rate and the amount of carbon in steel are directly proportional to the hardness achieved in martensitic transformation.
30) Iron possesses BCC crystal structure up to (in degree centigrade)?
Answer: A [ 768 ]
Description: Pure iron possesses either BCC or FCC crystal structure as its temperature increases from room temperature to its melting point. At room temperature to 910° C, it has BCC, between 910° C and 1410° C it has face-centered cubic, and from 1410° C to its melting point (1539° C), it returns to its BCC crystal structure.
31) Which of the following form of iron is magnetic?
Answer: A [ α ]
Description: The alpha form of iron is magnetic and stable at all temperatures, i.e., below 910° C.
32) Which of the following methods is best for examining surface flaws on the castings?
Answer: D [ Visual Inspection ]
Description: Visual inspection is a type of non -destructive testing technique that provides a means of detecting and examining the variety of surface flaws, such as surface finish, discontinuities, and surface cracks on the castings. This method is very cheap and widely used because most surface defects and roughness can be easily observed.
33) Which of the following types of light is preferred for using fluorescent penetrant in liquid penetrant testing (LPT) method?
Answer: D [ Ultraviolet light ]
Description: In the LPT method, the objective is accomplished by entrapment of the inspection liquid by the flaws followed by visual inspection of the surface under ultraviolet light (when using a fluorescent penetrant), and for visible dye penetrant normal light can be used for the inspection process.
34) Which of the following processes is preferred for preparing aluminum ingots for the liquid penetrant testing method?
Answer: C [ Acid Prickling ]
Description: When the liquid penetrant test is used for aluminum ingots, before the test, the surfaces of the aluminum ingots are prepared or treated with the acid pickle. This process is known as acid pickling, and it is recommended in preference to all other processes like caustic etching, machining, etc.
35) Which of the following inspections is used for detecting invisible surface defects in a nonmagnetic casting?
Answer: A [ Dye penetrant inspection ]
Description: The dye penetrant inspection method is mainly used to detect invisible surface defects in a nonmagnetic casting. The casting is cleaned by brushing, and then spraying or dipping of the casting is done into a dye containing a fluorescent material. Then for inspection, casting is dried and viewed in the darkness that reveals the discontinuities in the surface.
36) Which of the following methods is best for detecting interior flaws in the castings?
Answer: C [ Ultrasonic Inspection ]
Description: In the ultrasonic inspection, a beam of high-frequency sound waves is introduced into the material to detect interior flaws in the material. The sound wave travels through the material with some loss of energy and is reflected at the interfaces. It will be further analyzed to define the presence and location of flaws in the casting.
37) Which of the following was not a classification of a subject taking the MFFT?
Answer: B [ Slow accurate ]
Description: The subjects taking the MFFT, the subjects were then classified into four categories, namely, fast-accurates, reflectives, impulsive and slow-inaccurate. Slow-accurates were not one of the classifications.
38) Which of the following parameter is used to assess the magnetic ability of a material?
Answer: D [ Susceptibility ]
Description: Magnetic susceptibility is a measure to quantify a material's ability to undergo magnetization in an applied magnetic field. It is the ratio of magnetization (M) to the applied magnetic field intensity (H).
39) With an increase in temperature, the resistance of a semiconductor _________
Answer: A [ Decreases ]
Description: Semiconductors have a negative temperature coefficient of resistance; thus, resistance increases with decreasing temperature.
40) What is the polymerization of two or more chemically different monomers forming a long molecular chain?
Answer: A [ Copolymerization ]
Description: Copolymerization involves the polymerization of two or more different monomers to form a long chain molecule. A well-known 'Nylon 66' is a copolymer of hexamethylenediamine and adipic acid.
41) Which of the following is a secondary bond network of thermoplastics?
Answer: B [ 1-Dimensional ]
Description: Thermoplastics have a one-dimensional network of '2-degree' secondary bonds.
42) Which of the following are ceramics solids?
Answer: D [ Non-metallic, inorganic and amorphous solids ]
Description: Ceramics are non-metallic, inorganic, amorphous solids and are mostly oxides of metals. Ceramics possess low tensile strength and are brittle.
43) For an M10 grade RCC (Reinforced Cement Concrete), the cement ratio to aggregate to the sand is?
Answer: D [ 1:3:6 ]
Description: M10 grade of RCC have cement to aggregate to sand ratio equal to 1:3:6.
44) Which one of the following can act as a modifier in the glass-forming process?
Answer: D [ Magnesium oxide ]
Description: Magnesium oxide is used as a viscosity modifier, making glass melt viscosity in the desired range for proper formation of the filaments.
45) Which of the following is not a laminar composite?
Answer: C [ Woods ]
Description: Wood is not a laminar composite. Bimetallic, cladding, and paints are considered laminar composites.
46) In sandwich composites, which of the following material can be used for filling purposes?
Answer: D [ All of them ]
Description: Wood, cement, and polymer can be used to fill the gap in sandwich composites.
47) Which of the following has a greater impact on the longitudinal strength of reinforced composites?
Answer: A [ Fiber Strength ]
Description: Longitudinal strength of reinforced composites is directly proportional to their fiber strength.
48) Angle between side cutting edge and end cutting edge in the top surface plane of the tool.
Answer: D [ Nose Angle ]
Description: Nose angle is the angle between side cutting edge and end cutting edge.
49) What is the maximum allowed value of VB in mm for the HSS tool used with the cast iron workpiece for rough machining?
Answer: C [ 2 ]
Description: VB denotes the width of wear land. Maximum 2mm width of wear land is allowed in flank wear.
50) Which of the following tools is most suitable for very hard and brittle material?
Answer: C [ Carbides ]
Description: Carbides are very hard and have very good red hot hardness properties, hence most suitable for machining hard and brittle material.