1. Which of the following is a basic classification of Engineering Materials?
a) Metals
b) Non-Metals
c) Both Metals & Non-Metals
d) None of the mentioned
View Answer
Explanation: The two basic classifications of Engineering are:
i) Metals
ii) Non-Metals
2. Which of the following is not a property of engineering materials?
a) Mechanical properties
b) Chemical properties
c) Polymorphism
d) Electrical properties
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Explanation: The various material properties are:
i) Mechanical properties
ii) Physical properties
iii) Electrical properties
iv) Chemical properties
v) Thermal properties
vi) Magnetic properties
3. Which of the following is a type of Engineering Materials and is a Metal?
a) Asbestos
b) Ferrous Metals
c) Non-Ferrous Metals
d) Both b & c
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Explanation: The engineering materials are classified as:
i) Ferrous Metals
ii) Non-ferrous Metals
iii) Plastics
iv) Ceramics and Diamond
v) Composite Materials
vi) Nano-materials
4. Which of the following attributes explain why pure metals are not frequently used in engineering applications?
a) Softness
b) Hardness
c) Brittleness
d) Luster
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Explanation: Pure metals are soft and ductile, which is not ideal for most engineering applications. Therefore, alloys are used to fulfill the requirements. This explains why pure gold is mixed with impurities to make ornaments.
5. Which of the following is an example of a thermoplastic?
a) Melamine
b) Epoxide
c) Urethane
d) Acetal
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Explanation: Acetal is an example of engineering thermoplastics. These are the plastics that are typically employed in engineering applications due to high strength, environmental resistance, and physical properties. Other examples of engineering thermoplastics are ethenic, cellulose, polyether etc. Urethane, melamine, and epoxide are examples of engineering thermosetting plastics.
6. Which class of engineering ceramics generally includes lubricant materials?
a) Metalloids
b) Intermetallics
c) Sulphides
d) Carbides
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Explanation: Molybdenum disulfide (MoS2) and tungsten disulfide (WS2) are common sulfide materials used in lubrication. Metalloid elements like germanium and silicon are used as electronic devices. Intermetallics like Nickel aluminide are used in water coatings.
7. Which of the following is not a property of fiberglass?
a) Nonflammable
b) Reinforcement for plastics
c) Thermal insulation
d) Organic
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Explanation: Fiberglass is known as the glass that has been drawn into fine fibers. They are inorganic in nature which makes them greatly inert. They also exhibit a high strength to weight ratio, non-flammability, and resistance to heat. For engineering applications, they are used for thermal and acoustic insulation, and as reinforcements for plastics.
8. On average, what is the maximum use temperature of engineering ceramics?
a) 2860oC
b) 6815oC
c) 3400oC
d) 2760oC
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Explanation: Compared to most metals and plastics, ceramics have a very good limit of maximum use temperature. It lies around 2760oC for ceramics, while metals and plastics lay lower at 815oC and 260oC respectively.
9. How is the creep strength of ceramics when compared to other materials?
a) Low
b) High
c) Excellent
d) Zero
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Explanation: Engineering ceramics have good tensile strength, compressive strength, hardness, and excellent creep resistance. Metals usually have gold creep resistance, but plastics fair poorly.
10. Which of the following factors affect the mechanical properties of a material under applied loads?
a) Grain size
b) Shape of material
c) Content of alloys
d) Imperfection and defects
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Explanation: Contents of alloys improve or decrease the hardness and strength of materials. Finer grain sizes improve the strength of the material. Imperfection and defects reduce the strength of the material. Shape, however, has little or no effect on the material.
11. The compressive test is done on which of the following materials?
a) Aluminum
b) Thermocole
c) Cast iron
d) Gold
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Explanation: Since brittle materials are unsuitable for tension test, they are checked using a compressive test. Brittle materials such as cast iron, concrete, mortar, brick, and ceramics are commonly tested in compression.
12. Which term is used to define the temperature at which a substance changes its status from solid to liquid?
a) Melting point
b) Freezing point
c) Boiling point
d) Condensation point
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Explanation: The temperature at which a substance changes from solid state to liquid is known as the melting point; here the temperatures of solid and liquid are in equilibrium. The shift of liquid state to solid is known as the freezing point. The transition from gaseous state to liquid is known as condensation, while that of liquid to gaseous is known as the boiling point.
13. Electrolysis usually used for materials like _________
a) Silicon, antimony
b) Silver, tin
c) Zinc, cadmium
d) Aluminum, nickel
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Explanation: Since atomization results in oxidation of molten metal as it comes in contact with air, it is only used for materials like zinc and cadmium. Electrolysis is a standard electrolytic process which is used for materials like silver and tin. It is advantageous as it produces oxidation resistant powders.
14. Which of the following processes is not an application of thermoelectric effect?
a) Peltier effect
b) Ettingshausen effect
c) Seebeck effect
d) Thomson effect
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Explanation: Seebeck, Peltier, and Thomson are three distinct effects which make up the thermoelectric effect. Ettingshausen effect, however, is a separate thermoelectric phenomenon like the Nernst effect.
15. Which materials are to be tested using an F-scale?
a) Bronze, gunmetal, and beryllium copper
b) Thermoplastics
c) Case hardened steels
d) Copper and brass
View Answer
Explanation: The Rockwell hardness F-scale uses a 1/16 inch diameter steel ball indenter with a total indenting load of 60 kg. This is used for testing of copper and brass.
16. Which of these is not a function of alloy steels?
a) Improves ductility
b) Improves machinability
c) Increases strength
d) Reduces cost
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Explanation: Alloy steels are used to improve properties such as strength, hardness, ductility, grain structure, and machinability, among others. This, however, results in increased costs due to multiple elements involved in the process.
17. How does the Vicker’s hardness test differ from Brinell’s?
a) Type of indenter
b) Materials to be tested
c) Load applied
d) Duration of indentation
View Answer
Explanation: Similar to Brinell’s test, Vicker’s test also employs forcing of the indenter into the surface of metal for about 10-15 seconds. However, instead of a ball indenter, a pyramid-shaped indenter is used. This test is commonly also called the diamond-pyramid hardness test.
18. Which of the following is a characteristic of alumina?
a) Poor wear resistance
b) Good toughness
c) Good tensile strength
d) Excellent hardness
View Answer
Explanation: Aluminum oxide (Al2O3) is regarded as the oldest engineering ceramic. They have excellent hardness and wear resistance. They are stiffer and stronger than steels. Their tensile and toughness properties, however, can be improved by mixing them with zirconium.
19. Which is the primary element used for making stainless steel alloy?
a) Vanadium
b) Indium
c) Chromium
d) Zirconium
View Answer
Explanation: Stainless steels contain iron and a minimum of 10.5% of chromium. This gives it great resistance to corrosion. Therefore, stainless steels are often known as corrosion-resistant steels or chromium-bearing steels.
20. What disadvantage does silicon carbide have?
a) Thermal conductivity
b) Tensile strength
c) Cost
d) Oxidation resistance
View Answer
Explanation: Silicon carbide has excellent tensile strength, oxidation resistance, and the highest thermal conductivity among the common engineering ceramics. However, it is expensive and only available in limited shapes and sizes. It also has a low strength.
21. Which of the following is not a classification of aluminum alloys?
a) Cast alloys
b) Heat-treatable alloys
c) Wrought alloys
d) Crucible alloys
View Answer
Explanation: Aluminum alloys are categorized into wrought alloys, cast alloys, heat-treatable, and non heat-treatable alloys. An example of each is 2.5% Mg, 0.25% Cr, and rest Al (wrought), 12% Si and rest Al (cast), 0.4-0.9% Mg, 0.3-0.7% Si, and rest Al (heat-treatable), and (0.8-1.5% Mn and rest Al (non heat-treatable).
22. High conductivity copper is used ______
a) To raise softening temperature
b) In electrical engineering
c) To manufacture semiconductor elements
d) To reduce porosity
View Answer
Explanation: High conductivity copper contains over 99.9% copper, less than 0.005% of both lead and iron, along with low oxygen content. This copper finds its applications in the field of electrical engineering as it is a great conductor of electricity.
23. Which brass alloy is suitable for high-speed machining?
a) High tensile brass
b) Gilding metal
c) Muntz metal
d) Leaded brass
View Answer
Explanation: Leaded brass is used for high-speed machining due to its excellent strength and heat resistance. It contains 59% Cu, 39% Zn, and 2% Pb. It is also known as free cutting brass.
24. Which type of bearing bronze is the weakest?
a) Phosphorus bronze
b) Leaded bronze
c) Sintered bronze
d) Plain tin bronze
View Answer
Explanation: Leaded bronze is a Copper-base bearing alloy containing 75% Cu, 5% Sn, 18% Pb, and 2% Ni. They are less stronger than other bearing bronzes. However, they can sustain higher loads than white metals, at higher speeds.
25. Magnalium is an alloy of magnesium, ________
a) Nickel and Zinc
b) Nickel and Tin
c) Zirconium and Zinc
d) Zinc and Tin
View Answer
Explanation: Magnalium, although considered an aluminum alloy, may contain over 50% magnesium and small amounts of nickel and tin. They are commonly used for engineering applications and pyrotechnics.
26. Which polymer additive is used to remove parts from molds?
a) Reinforcements
b) Lubricants
c) Stabilizers
d) Plasticizers
View Answer
Explanation: Lubricants are used to remove parts from molds, make surfaces slippery, and prevent them from sticking to each other. They are also known as slip agents. Common lubricant additives are silicone, waxes, fatty acid amides, glycerides, petrolatum etc.
27. Which of the following carbides are used for cutting tools?
a) Chromium carbide
b) Silicon carbide
c) Tungsten carbide
d) Vanadium carbide
View Answer
Explanation: Tungsten carbide (WC) belongs to the carbide class of engineering ceramics. It is used for cutting tools. Silicon carbide and boron carbide are used as abrasive, whereas vanadium carbide and tantalum carbide are used as wear-resistant materials. Chromium carbide is used as wear coating.
28. Which of the following is not a type of protective coating?
a) Non-metallic
b) Metallic
c) Inorganic
d) Organic
View Answer
Explanation: A protective coating is generally defined as a layer of an inert substance which is applied to a material to prevent the chemical and electrochemical attack. These are classified into metallic, organic, and inorganic coatings.
29. Which of the following is an example of soft magnetic material?
a) Strontium
b) Neodymium
c) Permalloy
d) Alnico
View Answer
Explanation: Permalloy is a soft magnet mainly used in electrical and electronic applications. It is composed of roughly 45% nickel. It has a high relative permeability of around 2700.
30. Which of the following is an example of organic insulating material?
a) Asbestos
b) Slag
c) Wood-pulp
d) Charcoal
View Answer
Explanation: Thermal insulation materials are classified as either organic or inorganic. Silk, wool, wood-pulp, and sawdust are a few examples of organic materials. Some common inorganic insulating materials are glass wool, slag, charcoal, and coke powder.
31. Which of the following is a characteristic of asbestos minerals?
a) Heat resistance
b) Reacts with acids
c) Poor strength
d) Poor bonding
View Answer
Explanation: Asbestos minerals are highly preferred in their fibrous form. They possess high strength, surface area, and good bonding characteristics. They are also resistant to heat, acids, and moisture.
32. Which of the following is not a method of fabrication of rubber?
a) Vacuum forming
b) Buffing
c) Calendering
d) Compression molding
View Answer
Explanation: Some of the basic forming and fabrication techniques for rubber include compression molding, calendering, injection and transfer molding, and extrusion among others. Tumbling, trimming, and buffing are techniques of finishing this fabricated rubber.
33. What is the result of full annealing of hypoeutectoid steels?
a) Cementite
b) Coarse pearlite
c) Silicon
d) Bainite
View Answer
Explanation: Hypoeutectoid steels are heated above the A3 line and then cooled in the furnace. Then it removed from the furnace and then cooled at room temperature. This results in coarse pearlite with excess ferrite.
34. Which among the following is not an amorphous material?
a) Lead
b) Glass
c) Rubbers
d) Plastics
View Answer
Explanation: Materials in which the molecule is the basic structural solid and has an irregular structure are known as amorphous solid. Most amorphous materials are polymers such as plastics and rubbers. The most common amorphous material is glass.
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