The Ultimate Materials Science Practice Test!
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Questions and Answers
- 1.
1) The crystal structure of alfa iron is
- A.
(A) Simple Cubic
- B.
(B) Face centered cubic
- C.
(C) Body centered cubic
- D.
(D) Close packed hexagonal
Correct Answer
C. (C) Body centered cubicExplanation
The correct answer is (C) Body centered cubic. Body centered cubic (BCC) is a crystal structure in which each atom is surrounded by eight neighboring atoms, with one atom located at the center of the unit cell. This structure is commonly found in metals such as iron. Simple Cubic (A) has atoms located only at the corners of the unit cell, Face centered cubic (B) has atoms located at the corners and center of each face of the unit cell, and Close packed hexagonal (D) has a hexagonal arrangement of atoms with a close-packed layer and a second layer directly above it.Rate this question:
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- 2.
2) Which of the following metal has lowest melting point?
- A.
(A) Antimony
- B.
(B) Tin
- C.
(C) Silver
- D.
(D) Zinc
Correct Answer
B. (B) TinExplanation
Tin has the lowest melting point compared to the other metals listed. This means that it requires the least amount of heat to change from a solid to a liquid state. Antimony, silver, and zinc all have higher melting points than tin.Rate this question:
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- 3.
3) Metal with hexagonal close packed structure is
- A.
(A) silver
- B.
(B) Iron
- C.
(C) Magnesium
- D.
(D) Aluminium
Correct Answer
C. (C) MagnesiumExplanation
Magnesium has a hexagonal close packed (HCP) structure. In this structure, the atoms are arranged in a hexagonal pattern with each atom surrounded by six nearest neighbors. This arrangement allows for efficient packing of atoms, resulting in a dense and stable structure. Silver, iron, and aluminum do not have a hexagonal close packed structure.Rate this question:
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- 4.
4) The structures which have the highest packing of atoms are
- A.
(A) hexagonal close packed lattice
- B.
(B) body central cubic lattice
- C.
(C) simple cubic lattice
- D.
(D) none of the above
Correct Answer
A. (A) hexagonal close packed latticeExplanation
The correct answer is (A) hexagonal close packed lattice. Hexagonal close packed (HCP) lattice has the highest packing of atoms among the given options. In an HCP lattice, the atoms are arranged in a close-packed manner with each atom surrounded by 12 nearest neighbors. This arrangement maximizes the number of atoms that can be packed together in a given space, resulting in the highest packing efficiency. Body central cubic lattice and simple cubic lattice have lower packing efficiencies compared to HCP lattice. Therefore, the HCP lattice is the correct answer.Rate this question:
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- 5.
5) In Brinell hardness tester the load for aluminium is
- A.
A) 300 kg
- B.
B)1500 kg
- C.
C) 1000 kg
- D.
D)500 kg
- E.
E)100 kg
Correct Answer
D. D)500 kgExplanation
In Brinell hardness testing, the load applied to the material being tested determines the hardness value. For aluminium, the load used is 500 kg. This means that a force of 500 kg is applied to the surface of the aluminium specimen, and the resulting indentation is measured to determine the hardness value.Rate this question:
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- 6.
6) In Brinell hardness testing the timer for loading is
- A.
A) 1 second
- B.
B) 2 seconds
- C.
C) 5 seconds
- D.
D) 15 seconds
- E.
E) 1 minute
Correct Answer
D. D) 15 secondsExplanation
In Brinell hardness testing, the timer for loading is set to 15 seconds. This means that the test material is subjected to a specific load for a duration of 15 seconds. This loading time is important because it allows for the proper indentation to be made on the material's surface, which is then measured to determine its hardness. A shorter loading time may not provide enough pressure for a clear indentation, while a longer loading time may result in excessive deformation of the material. Therefore, a loading time of 15 seconds is considered appropriate for accurate Brinell hardness testing.Rate this question:
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- 7.
7) In Brinell hardness testing the minimum thickness of the specimen should be
- A.
A) Less than 5 times the depth of impression
- B.
B) Less than 10 times the depth of impression
- C.
C) Equal to 10 times the depth of impression
- D.
D) More than 10 times the depth of impression
- E.
E) Thickness of specimen has no relevance to the depth of impression
Correct Answer
D. D) More than 10 times the depth of impressionExplanation
In Brinell hardness testing, the minimum thickness of the specimen should be more than 10 times the depth of impression. This requirement ensures that the specimen is thick enough to prevent any deformation or distortion caused by the impression. If the specimen is too thin, it may result in inaccurate hardness measurements as the material may not be able to withstand the indentation force without deforming. Therefore, a minimum thickness greater than 10 times the depth of impression is necessary to ensure reliable and accurate hardness measurements.Rate this question:
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- 8.
8) Indenter used in Vickers hardness testing machine is
- A.
A) 25 mm dia ball
- B.
B) 15 mm dia ball
- C.
C) 10 mm dia ball
- D.
D) Conical indentor with 120? apex angle
- E.
E) Diamond square-based pyramid
Correct Answer
E. E) Diamond square-based pyramidExplanation
The indenter used in Vickers hardness testing machine is a diamond square-based pyramid. This type of indenter is commonly used in Vickers hardness testing because it provides a more accurate and precise measurement of hardness. The diamond indenter creates a square-shaped indentation on the material being tested, and the size of this indentation is used to calculate the hardness value. The diamond indenter is preferred over other options like ball indenters because it is harder and can be used to test a wider range of materials.Rate this question:
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- 9.
9) Angularity of the square base pyramid in Vickers hardness tester is
- A.
A) 90
- B.
B)11
- C.
C) 120
- D.
D)136
- E.
E)150
Correct Answer
D. D)136Explanation
The angularity of the square base pyramid in a Vickers hardness tester is 136.Rate this question:
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- 10.
10) The property which enables metals to be drawn into wire is known as
- A.
A) Malleability
- B.
B)Ductility
- C.
C)Straining
- D.
D)Plastic deformation
- E.
E) Elastic deformation
Correct Answer
B. B)DuctilityExplanation
Ductility is the property of a material that allows it to be stretched or drawn into a wire without breaking. This property is particularly important for metals, as it allows them to be easily formed into different shapes and sizes. Malleability, on the other hand, refers to the ability of a material to be deformed under compression, while plastic deformation and elastic deformation are general terms that describe the behavior of materials under stress. Straining is not a specific property related to the ability of metals to be drawn into wire.Rate this question:
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- 11.
11) Slow plastic deformation of metals under a constant stress is known as
- A.
A) Fatigue
- B.
B)Proof deformation
- C.
C) Gradual deformation
- D.
D) Creep
- E.
E) Endurance failure
Correct Answer
D. D) CreepExplanation
Creep is the correct answer because it refers to the slow plastic deformation of metals under a constant stress. This phenomenon occurs over time and at elevated temperatures, causing the material to gradually deform under the applied stress. Creep can lead to structural failure if not properly accounted for in engineering design.Rate this question:
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- 12.
12) In which of the following cases creep is an important consideration?
- A.
A) Cast iron water pipes
- B.
B)Cycle chains
- C.
C) Gas turbine blades
- D.
D) Steam engine flywheel
- E.
E) All of the above
Correct Answer
C. C) Gas turbine bladesExplanation
Creep is an important consideration in the case of gas turbine blades. Creep refers to the slow and permanent deformation of a material under constant stress over time. Gas turbine blades operate at high temperatures and experience significant mechanical stress, making them susceptible to creep. The high temperatures can cause the material to soften and deform, leading to a loss of structural integrity and potentially catastrophic failure. Therefore, creep must be carefully considered and managed in the design and operation of gas turbine blades.Rate this question:
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- 13.
13) The rollers of a cycle chain are subjected to
- A.
A) Compressive stress
- B.
B) Tensile stress
- C.
C) Shear stress
- D.
D) Fatigue stress
- E.
E) Creep stress
Correct Answer
D. D) Fatigue stressExplanation
The correct answer is D) Fatigue stress. The rollers of a cycle chain are subjected to fatigue stress because they undergo repeated cyclic loading as the chain moves around the gears and sprockets. This repeated loading can cause small cracks to develop in the rollers, leading to eventual failure.Rate this question:
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- 14.
14) Which metal has the lowest melting point?
- A.
A) Iron
- B.
B) Copper
- C.
C) Silver
- D.
D) Magnesium
- E.
E) Aluminium
Correct Answer
A. A) IronExplanation
Iron has the lowest melting point among the given options. This means that iron requires the lowest amount of heat to change from a solid to a liquid state.Rate this question:
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- 15.
15) Which of the following metals has highest specific gravity?
- A.
A) Iron
- B.
B) Silver
- C.
C) Copper
- D.
D) Aluminium
- E.
E) Brass
Correct Answer
B. B) SilverExplanation
Silver has the highest specific gravity among the given options. Specific gravity is a measure of density and represents the ratio of the density of a substance to the density of a reference substance (usually water). Since silver has a higher density compared to the other metals listed, it has a higher specific gravity.Rate this question:
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- 16.
16) Which of the following metal has the lowest specific gravity?
- A.
A) Monal metal
- B.
B) Magnesium
- C.
C) Copper
- D.
D) Bronze
- E.
E) Cast iron
Correct Answer
B. B) MagnesiumExplanation
Magnesium has the lowest specific gravity among the given options. Specific gravity is a measure of the density of a substance compared to the density of water. Since magnesium has a lower density than water, its specific gravity is less than 1. This means that magnesium is less dense than water and will float on its surface. In comparison, the other metals listed have higher densities and therefore higher specific gravities.Rate this question:
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- 17.
17) Brinell hardness of nitrided surface may be of the order of
- A.
A) 100
- B.
B) 150 to 200
- C.
C) 200 to 250
- D.
D) 300 to 450
- E.
E) More than 600
Correct Answer
E. E) More than 600Explanation
Nitriding is a surface hardening process in which nitrogen is diffused into the surface of a metal to increase its hardness and wear resistance. The Brinell hardness scale measures the hardness of a material by indenting a spherical indenter into the surface of the material and measuring the diameter of the resulting indentation. Nitrided surfaces typically have a very high hardness, often exceeding 600 on the Brinell hardness scale. Therefore, the correct answer is E) More than 600.Rate this question:
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- 18.
18) Vicker's hardness number of diamond could be of the order of
- A.
A) 15000
- B.
B)12000
- C.
C) 8000
- D.
D)4000
- E.
E) 800
Correct Answer
C. C) 8000Explanation
Diamond is known to be one of the hardest substances on Earth. Vickers hardness number is a measure of a material's resistance to indentation. A higher Vickers hardness number indicates a harder material. Therefore, it is reasonable to expect that the Vickers hardness number of diamond would be relatively high. Option C) 8000 is the highest value among the given options, making it the most likely answer.Rate this question:
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- 19.
19) Which of the following is a noble metal?
- A.
A) Aluminium
- B.
B) Stainless steel
- C.
C) Nickel
- D.
D) Platinum
- E.
E) Chromium
Correct Answer
D. D) PlatinumExplanation
Platinum is considered a noble metal because it is resistant to corrosion and oxidation. It is also known for its high melting point and durability. These properties make it highly valuable and useful in various industries, including jewelry, electronics, and automotive.Rate this question:
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- 20.
20) Lowest melting point may be expected for
- A.
A) Aluminium
- B.
B) Brass
- C.
C) Copper
- D.
D) Lead
- E.
E) Zirconium
Correct Answer
D. D) LeadExplanation
Lead has the lowest melting point among the given options. This is because lead is a heavy metal with a low melting point of 327.5°C (621.5°F). In comparison, aluminium has a melting point of 660.3°C (1220.5°F), brass has a melting point of around 900-940°C (1652-1724°F), copper has a melting point of 1084.62°C (1984.32°F), and zirconium has a melting point of 1852°C (3366°F). Therefore, lead is the correct answer as it has the lowest melting point among the options provided.Rate this question:
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- 21.
21) In order to observe the grain size of steel samples under microscope, the magnification should be the order of
- A.
A)2
- B.
B)10
- C.
C)20
- D.
D)100
- E.
E)1500
Correct Answer
D. D)100Explanation
To observe the grain size of steel samples under a microscope, a higher magnification is required. A magnification of 100x would provide a clear and detailed view of the grains. Lower magnifications such as 2x or 10x would not provide enough detail to accurately observe the grain structure, while higher magnifications such as 1500x would be excessive and may result in a distorted image. Therefore, a magnification of 100x is the most suitable option for observing the grain size of steel samples under a microscope.Rate this question:
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- 22.
22) There are 14 atoms in a unit cell of
- A.
A) Body centred cubic space lattice
- B.
B) Face centred cubic space lattice
- C.
C) Close packed hexagonal space lattice
- D.
D) All of the above
- E.
E) None of the above
Correct Answer
B. B) Face centred cubic space latticeExplanation
A face-centered cubic (FCC) space lattice is a type of crystal structure in which the lattice points are located at the corners and centers of each face of the unit cell. In an FCC lattice, there are 4 atoms located at each of the corners of the unit cell and 1 atom located at the center of each face. Therefore, the total number of atoms in a unit cell of an FCC lattice is 4 + 1 = 5. Since the given answer states that there are 14 atoms in a unit cell, it is not correct.Rate this question:
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- 23.
23) The coordination number of NaCl is
- A.
A) 2
- B.
B) 3
- C.
C) 6
- D.
D) 8
- E.
E) 9
Correct Answer
C. C) 6 Explanation
The coordination number of NaCl is 6 because in the crystal structure of NaCl, each Na+ ion is surrounded by 6 Cl- ions and each Cl- ion is surrounded by 6 Na+ ions. This means that each ion is in contact with 6 ions of opposite charge, resulting in a coordination number of 6.Rate this question:
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- 24.
24) Maximum hardness that can be achieved in plain carbon steel is of the order of
- A.
A) 50 Rockwell 'C'
- B.
B) 66 - 67 Rockwell 'C'
- C.
C) 100 - 150 Rockwell 'C'
- D.
D) 80-85 Rockwell 'C'
- E.
E) There is no such limit for hardness
Correct Answer
B. B) 66 - 67 Rockwell 'C' -
- 25.
25) The number of atoms per unit cell in BCC is
- A.
A) 9
- B.
B) 3
- C.
C) 4
- D.
D) 6
- E.
E) 8
Correct Answer
A. A) 9Explanation
In a Body-Centered Cubic (BCC) crystal structure, there is one atom at each of the eight corners of the unit cell and one atom at the center of the unit cell. Therefore, there are a total of nine atoms per unit cell in BCC.Rate this question:
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- 26.
26) Just as strong is opposite of weak likewise elastic is opposite of
- A.
A) Hard
- B.
B) Soft
- C.
C) Rigid
- D.
D) Inelastic
- E.
E) Ductile
Correct Answer
C. C) RigidExplanation
The word "elastic" refers to something that is flexible and can stretch or rebound easily. The opposite of this would be something that is not flexible and cannot easily stretch or rebound, which is the definition of "rigid". Therefore, "rigid" is the correct opposite of "elastic".Rate this question:
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- 27.
27) The crystal structure of most of the common metals is
- A.
A) Hexagonal
- B.
B) Cubic
- C.
C)Orthorhombic
- D.
D) Any of the above
- E.
E) None of the above
Correct Answer
B. B) CubicExplanation
Most of the common metals have a cubic crystal structure. This means that the atoms are arranged in a regular, repeating pattern with equal distances between them in all directions. The cubic structure can be further classified into three types: face-centered cubic (FCC), body-centered cubic (BCC), and simple cubic (SC). In the FCC structure, there is an atom at each corner of the unit cell and one in the center of each face. In the BCC structure, there is an atom at each corner and one in the center of the unit cell. The SC structure has an atom at each corner only. Since the question does not specify which type of cubic structure, the correct answer is "Cubic".Rate this question:
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- 28.
28) All of the following are magnetic materials EXCEPT:
- A.
A) Nickel
- B.
B) Cobalt
- C.
C) Iron
- D.
D) Zinc
- E.
E) Cast iron
Correct Answer
D. D) ZincExplanation
Zinc is not a magnetic material. While nickel, cobalt, iron, and cast iron are all magnetic materials, zinc does not exhibit magnetic properties.Rate this question:
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- 29.
29) Which of the following materials are usually most ductile?
- A.
A) Hexagonal close-packed lattice
- B.
B) Face centred cubic lattice
- C.
C) Body centred lattice
- D.
D) Amorphous
- E.
E) Non-metallic
Correct Answer
B. B) Face centred cubic latticeExplanation
Face centred cubic (FCC) lattice structures are usually the most ductile because they have a high degree of symmetry and closely packed atoms. This arrangement allows for easy movement of atoms and dislocations, which contributes to the material's ability to deform without breaking. In contrast, materials with hexagonal close-packed (HCP), body centred (BCC), or amorphous structures have less symmetry and may have more restricted movement of atoms, making them less ductile. Non-metallic materials, such as ceramics, generally have a different atomic arrangement and bonding, which also affects their ductility.Rate this question:
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- 30.
30) The crystal structure of brass is
- A.
A) BCC
- B.
B) FCC
- C.
C) HCP
- D.
D) Orthorhombic
- E.
E) Mixture of all above
Correct Answer
B. B) FCCExplanation
Brass is an alloy made primarily of copper and zinc. The crystal structure of brass is face-centered cubic (FCC), which means that the atoms are arranged in a cubic lattice with additional atoms located at the center of each face. This arrangement allows for close packing of atoms and results in a relatively dense and stable structure.Rate this question:
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- 31.
31) Machinability of metal depends on
- A.
A) Hardness
- B.
B) Hardness and tensile strength
- C.
C) Brittleness
- D.
D) Brittleness and toughness
Correct Answer
B. B) Hardness and tensile strengthExplanation
The machinability of a metal refers to how easily it can be machined or shaped using various cutting tools. Hardness and tensile strength are two important factors that influence machinability. A metal with high hardness may be difficult to cut or shape, while a metal with high tensile strength may cause excessive tool wear. Therefore, both hardness and tensile strength play a significant role in determining the machinability of a metal.Rate this question:
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- 32.
32) Which of the following metal does not have face centred cubic structure?
- A.
A) Copper
- B.
B) Silver
- C.
C) Tin
- D.
D) Lead
- E.
E) Nickel
Correct Answer
C. C) Tin Explanation
Tin does not have a face centred cubic structure.Rate this question:
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- 33.
33) Which of the following metal has face centred cubic structure?
- A.
A) Zinc
- B.
B) Gold
- C.
C) Magnesium
- D.
D) Cadmium
- E.
E) Tin
Correct Answer
B. B) GoldExplanation
Gold has a face centred cubic (FCC) structure. In an FCC structure, the atoms are arranged in a cubic lattice with an atom at each corner of the cube and an atom at the center of each face. Gold is known for its high ductility and malleability, which can be attributed to its FCC structure. This arrangement allows for close packing of atoms, resulting in strong metallic bonding and the ability of gold to be easily deformed without breaking.Rate this question:
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- 34.
34) Which of the following material has body centred cubic structure?
- A.
A) Molybdenum
- B.
B) Cadmium
- C.
C) Glass
- D.
D) Magnesium
- E.
E) Zinc.
Correct Answer
A. A) MolybdenumExplanation
Molybdenum has a body-centered cubic (BCC) structure. In this structure, each atom is located at the center of a cube, with eight atoms at the corners and one atom in the center of the cube. Molybdenum's BCC structure gives it certain properties, such as high melting point and good strength at high temperatures.Rate this question:
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- 35.
35) Which of the following material does not have body centred cubic structure?
- A.
A) Vanadium
- B.
B) Potassium
- C.
C) Lithium
- D.
D) Zirconium
- E.
E) Chromium
Correct Answer
D. D) ZirconiumExplanation
Zirconium does not have a body centred cubic (BCC) structure. The BCC structure consists of atoms arranged in a cube with one atom at each corner and one atom in the centre of the cube. Vanadium, potassium, lithium, and chromium all have BCC structures, but zirconium has a different crystal structure known as hexagonal close-packed (HCP).Rate this question:
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- 36.
36) Which of the following element has hexagonal close packed structure?
- A.
A) Aluminium
- B.
B) Molybdenum
- C.
C) Cadmium
- D.
D) Chromium
- E.
E) Lead
Correct Answer
C. C) CadmiumExplanation
Cadmium has a hexagonal close-packed structure. In this structure, the atoms are arranged in a close-packed pattern with each atom surrounded by six nearest neighbors forming a hexagonal shape. This arrangement allows for efficient packing of atoms, resulting in a high density of the material. Cadmium, being a transition metal, can adopt different crystal structures depending on temperature and pressure, but at room temperature and normal pressure, it forms a hexagonal close-packed structure.Rate this question:
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- 37.
37) Which of the following material does not have hexagonal close packed structure?
- A.
A) Magnesium
- B.
B) Alpha iron
- C.
C) Titanium
- D.
D) Zinc
- E.
E) Cadmium
Correct Answer
B. B) Alpha ironExplanation
The correct answer is B) Alpha iron. Alpha iron, also known as ferrite, has a body-centered cubic (BCC) structure, not a hexagonal close packed (HCP) structure. Magnesium, titanium, zinc, and cadmium all have HCP structures.Rate this question:
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- 38.
38) When steel is made from phosphatic iron, it is likely to be
- A.
A) Malleable
- B.
B) Ductile
- C.
C) Hard
- D.
D) Brittle
- E.
E)Tough
Correct Answer
D. D) BrittleExplanation
When steel is made from phosphatic iron, it is likely to be brittle. This is because phosphorus is a known impurity in iron that reduces its ductility and toughness. High levels of phosphorus can lead to the formation of brittle phases in the steel, making it prone to cracking and breaking under stress. Therefore, steel made from phosphatic iron is not malleable, ductile, or tough, but rather brittle.Rate this question:
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- 39.
39) Which metal has the highest melting point?
- A.
A) Antimony
- B.
B) Chromium
- C.
C) Gold
- D.
D) Stainless steel
Correct Answer
B. B) ChromiumExplanation
Chromium has the highest melting point among the given options. It is a transition metal with a melting point of 1907 degrees Celsius or 3465 degrees Fahrenheit. Chromium's high melting point is due to its strong metallic bonds, which require a significant amount of energy to break and transition from a solid to a liquid state. This property makes it useful in applications that require high temperature resistance, such as in the production of stainless steel.Rate this question:
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- 40.
40) In metallography, microscopic method provides information about _____
- A.
A. impurities in a metal
- B.
B. location and extent of segregation
- C.
C. uniformity of structure
- D.
D. all of the above
Correct Answer
A. A. impurities in a metalExplanation
The microscopic method in metallography provides information about impurities in a metal. This method allows for the examination of the microstructure of a metal sample, revealing any impurities present. By analyzing the composition and distribution of these impurities, researchers can gain insights into the quality and purity of the metal. This information is crucial for understanding the properties and behavior of the metal, as well as for quality control purposes in industries that rely on metals.Rate this question:
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- 41.
41) The study of metallographic includes ____
- A.
A. alloy constituents
- B.
B. failure analysis
- C.
C. metal structure
- D.
D. all of the above
Correct Answer
D. D. all of the aboveExplanation
The study of metallography involves examining the structure and composition of metals and alloys. This includes analyzing alloy constituents, conducting failure analysis to understand the reasons for material failure, and studying the metal structure to determine its properties and behavior. Therefore, option d, "all of the above," is the correct answer as it encompasses all the aspects mentioned in the question.Rate this question:
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- 42.
42) Which of the following is an etching reagent used for carbon steels?
- A.
A. Nitric acid
- B.
B. Picric acid
- C.
C. Both a. and b.
- D.
D. None of the above
Correct Answer
C. C. Both a. and b.Explanation
Both nitric acid and picric acid can be used as etching reagents for carbon steels. Nitric acid is commonly used for general etching of carbon steels, while picric acid is often used for revealing grain boundaries and other microstructural features. Therefore, the correct answer is c. Both a. and b.Rate this question:
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- 43.
43) The component deforming progressively under load at high temperatures is called as
- A.
A. Resilience
- B.
B. Creep
- C.
C. Fatigue
- D.
D. All of the above
Correct Answer
C. C. FatigueExplanation
The correct answer is c. Fatigue. Fatigue refers to the progressive deformation of a component under load at high temperatures. This is different from resilience, which is the ability of a material to absorb energy and return to its original shape after being deformed. Creep is the gradual deformation of a material under constant stress, usually at high temperatures. Therefore, the correct answer is fatigue, as it specifically refers to the deformation of a component under load at high temperatures.Rate this question:
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- 44.
44) Hardness of a material enables it to resist _______
- A.
A. abrasion
- B.
B. penetration
- C.
C. plastic deformation
- D.
D. all of the above
Correct Answer
D. D. all of the aboveExplanation
The hardness of a material enables it to resist abrasion, penetration, and plastic deformation. When a material is hard, it is less likely to be scratched or worn away by rubbing or friction (abrasion). It is also less likely to be pierced or penetrated by a sharp object (penetration). Additionally, a hard material is less likely to undergo permanent deformation when subjected to a load or force (plastic deformation). Therefore, all of the above options are correct.Rate this question:
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- 45.
45) The hardness is the property of a material due to which it
- A.
A. can be drawn into wires
- B.
B. breaks with little permanent distortion
- C.
C. can cut another metal
- D.
D. can be rolled or hammered into thin sheets
Correct Answer
C. C. can cut another metalExplanation
The correct answer is C. can cut another metal. Hardness is a measure of a material's resistance to deformation, particularly when it comes to scratching or cutting. A material that is hard will be able to cut or scratch another material that is softer than it. Therefore, the property of hardness allows a material to cut another metal.Rate this question:
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- 46.
46) The ability of a material to absorb energy in the plastic range is called
- A.
A. resilience
- B.
B. creep
- C.
C. fatigue strength
- D.
D. toughness
Correct Answer
A. A. resilienceExplanation
Resilience refers to the ability of a material to absorb energy and deform under stress without undergoing permanent deformation or failure. It is specifically related to the plastic range, which is the range of deformation where the material can still return to its original shape after the stress is removed. Therefore, resilience is the correct term to describe the ability of a material to absorb energy in the plastic range. Creep refers to the gradual deformation of a material under constant stress, fatigue strength is the ability of a material to resist repeated loading, and toughness is the ability of a material to absorb energy without fracturing.Rate this question:
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- 47.
47) Closed packed hexagonal space lattice is found in
- A.
A.zinc, magnesium, cobalt, cadmium, antimony and bismuth
- B.
B.gamma-iron, aluminium, copper, lead, silver and nickel
- C.
C.alpha-iron, tungsten, chromium and molybdenum
- D.
D.none of the above
Correct Answer
A. A.zinc, magnesium, cobalt, cadmium, antimony and bismuthExplanation
Closed packed hexagonal space lattice refers to a crystal structure in which the atoms are arranged in a close-packed hexagonal pattern. This arrangement is found in zinc, magnesium, cobalt, cadmium, antimony, and bismuth. These elements have a similar atomic radius and bonding characteristics that allow them to form a hexagonal lattice structure. Gamma-iron, aluminium, copper, lead, silver, nickel, alpha-iron, tungsten, chromium, and molybdenum do not have this specific lattice structure.Rate this question:
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- 48.
48) The material in which the atoms are arranged regularly in some directions but not in others, is called
- A.
A. amorphous material
- B.
B. mesomorphous material
- C.
C. crystalline material
- D.
D. none of these
Correct Answer
B. B. mesomorphous materialExplanation
Mesomorphous material refers to a material in which the arrangement of atoms is regular in some directions but not in others. This means that the material has some level of order or structure, but it is not fully crystalline. Amorphous materials do not have any long-range order, crystalline materials have a highly ordered arrangement of atoms, and "none of these" is not a valid option as mesomorphous material is a specific category of materials.Rate this question:
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- 49.
49) Crystal structure of a material is, generally, examined by
- A.
A.naked eye
- B.
B.optical microscope
- C.
C.metallurgical microscope
- D.
D.X-ray techniques
Correct Answer
C. C.metallurgical microscopeExplanation
The crystal structure of a material is typically examined using a metallurgical microscope. This type of microscope is specifically designed to observe the microstructure of metals and alloys. It uses a combination of reflected light and polarized light to enhance the contrast and visibility of the crystal structure. The metallurgical microscope also allows for the examination of different features such as grain boundaries, phase boundaries, and defects in the material. X-ray techniques, while useful for other types of analysis, are not typically used for examining crystal structures directly.Rate this question:
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- 50.
50) Which of the following material has maximum ductility?
- A.
A. Mild steel
- B.
B. Copper
- C.
C. Nickel
- D.
D. Aluminium
Correct Answer
A. A. Mild steelExplanation
Mild steel has the maximum ductility among the given options. Ductility refers to the ability of a material to undergo plastic deformation without fracturing. Mild steel is known for its high ductility, which means it can be easily stretched or bent without breaking. This property makes it suitable for various applications such as construction, automotive, and manufacturing industries. Copper, nickel, and aluminium also have good ductility, but mild steel surpasses them in terms of maximum ductility.Rate this question:
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