ENG 10004 EXAM Practice
57. Which of the following factors have an effect on the results of ceramic flexural tests A. Temperature B. Strain(stress) rate C. Sample shape D. All of them
D
58. Identify the material with the best fracture toughness: A. Diamond B. Polypropylene C. Concrete D. Steel
D
12. Brittle failure may be characterized by A. Intergranular failure B. No extension under a tensile load C. Microvoid Coalescence D. Necking in a tensile sample
B
12. Glasses are: A. Crystalline materials B. Amorphous materials C. Semi crystalline materials D. Can have any of these structures
B
14. Tetrahedal bonding is characteristic of A. Ionic bonds B. Covalent bonds C. Metallic bonds D. Van der Waals bonds
B
14. Which of the following materials may form isotropic solids? A. Fibre reinforced Polymers B. Cast Metal Alloys C. Laminar Composites D. Piezo electric devices
B
15. Graphite is a good lubricant because A. Sheets of atoms are bonded together covalently B. The sheets are bonded to one another by van der Waals bonds C. The atoms in the sheets are bonded covalently to one another D. Sheets of atoms are bonded together ionically
B
1. The energy difference between adjacent energy levels of the hydrogen atom A. Decrease with increasing energy B. Increase with increasing energy C. Are independent of energy D. Do not change between adjacent energy levels
A
10. If you decrease the rate of deformation in tensile testing of composites: A. Tensile strength decreases B. Tensile strength increases C. Elongation decreases D. Modulus of elasticity increases
A
10. When a metal is put under hydrostatic tension it: A. Contracts B. Extends C. Explodes D. Shears
A
11. Which of these materials do not have covalent bonds: A. Metals B. Plastics C. Ceramics D. Carbon fibre reinforced composites
A
13. What is the predominant type of bonding for Sodium Chloride(NaCl)? A. Ionic B. Hydrogen C. Covalent D. Metallic
A
16. Diamond has a far higher yield strength than copper wire. The reason for this A. covalent bonds in diamond cause dislocations to be immobile B. Diamond is highly perfect and so does not contain a significant number of dislocations C. Diamond can be considered a ceramic D. Copper wire is usually annealed.
A
16. In defining Miller indices for planes in a crystal, we set up coordinate axes A. Along the edges of the unit cell B. Along the [100] directions C. Perpendicular to the face of the unit cell D. Along the (111) planes
A
17. A metal has a density of 7.250 g/cm3 and an atomic weight of 50.990 g/mol. For this metal that has the body-centred cubic crystal structure, its atomic radius (in nm ie m x 10-9 ) is closest in value to . A. 0.124 nm B. 1.240 nm C. 0.0124 nm C. 12.40 nm
A
18. For the body-centred cubic crystal structure: how many atoms are associated with each unit cell? A. 2 B. 4 C. 12 D. 16
A
19. Aluminium (A) has an FCC arrangement of atoms. The radius of A = 1.423Å (Å = 10 -10 m). The lattice parameter, 'a" of the A unit cell is closest in value to A. 4.05 Å B. 8.10 Å C. 12.20 Å D. 16.60 Å
A
2. The electron wave in motion around an atom must take a closed path because A. The electron is confined within the atom B. The electron is able to escape the atom C. The neutron is confined to the atom D. The neutron is able to escape the atom
A
20. The area of the (110) plane in an FCC unit cell whose atoms have a radius R, may be given by the relation: A. (8√2 )R2 B. √3 R2 C. (16√3) R2 D. (4/√3) R2
A
23. The unit cell of chromium is cubic and contains two atoms. If the density of chromium is 7.19 Mg/m3, Avogradro's number is 6.023 x 1023 mol/mole, and the atomic mass of chromium is 52. An estimate of the lattice constant (parameter) a0 of chromium is closest in value to A. 0.2884 x 10-9 m B. 0.1442 x 10-9 m C. 0.4882 x 10-9 m D. 0.2441 x 10-9 m
A
30. The three sequential stages of the ductile failure of a metal may be described as: A. necking, coalescence of voids, crack travels at 45 degrees to form a cup cone failure B. coalescence of voids, necking, , crack travels at 45 degrees to form a cup cone failure C. necking, crack travels at 45 degrees to form a cup cone failure and finally coalescence of voids. D. crack travels at 45 degrees to form a cup cone failure followed by necking and coalescence of voids
A
32. A fatigue test is made with a maximum stress of 172 MPa and a minimum stress of -27.6 MPa. The range of stress is closest in value to: A. 199.8 MPa B. 99.9 MPa C. 72.3 MPa D. -0.16 MPa
A
37. Which material has the highest fracture toughness? A. Steel B. Polypropylene C. Epoxy D Concrete
A
41. If you decrease the temperature of tensile testing of a fibre reinforced material, what will happen to only one of the following properties of your material? A. The modulus of elasticity increases. B. The modulus of elasticity decreases C. The elongation increases D. The tensile strength decreases
A
41. In the corrosion of metals, oxidation is the process by which A. an atom gives up an electron or electrons to become a cation B. an atom gains an electron or electrons to become a cation C. an atom gives up an electron or electrons to become an anion D. an atom gains an electron or electrons to become a cation
A
44. Which concrete test method is not standardized? A. Tensile test B. Compressive test C. Three point bending D. Four point bending.
A
49. In the life cycle of an aluminium beverage can, the highest environmental impact is incurred during which phase of its life cycle? A. extraction and production of ingot B. rolling C. manufacturing of can D. disposal
A
5. The elements in any one group of the periodic table are similar because A. They all contain the same number of electrons in the outermost sub shell. B. They do not all contain the same number of electrons in the outermost shell. C. They all contain the same number of protons in the innermost sub shell D. They all do not contain the same number of protons in the innermost sub shell
A
55. The typical test for concrete materials is A. Compression test B. Impact test C. Tensile test D. Creep test
A
56. The reason why concrete is mixed with more water then it is necessary for hydration reactions to occur is: A. To give concrete sufficient workability B. To make it stronger C. To increase concrete durability D. To cut the cost of concrete
A
7. The electrostatic nature of ionic bonding makes it A. Non-directional B. Weak C. Directional D. Strong
A
7. The movement of a dislocation through a crystal is known as A. Slip. B. Burgers' vector. C. Permanent deformation. D. Elastic deformation.
A
9. Metallic materials expand when heated because: A. The mean interatomic distance increases as the thermal energy of the atoms increases B. The heat takes up extra volume forcing the material to expand C. The metal melts D. There are more bonds being formed
A
Combinations of properties are important in evaluating the usefulness of materials mechanical properties. A modern approach to selecting materials is by using specialized charts which may plot A. Specific stiffness versus specific strength B. Stiffness versus stress C. Young's modulus versus weight D. Stress versus strain
A
In the life cycle of an aluminium beverage can, the highest environmental impact is incurred during which phase of its life cycle? A. extraction and production of ingot B. rolling C. manufacturing of can D. disposal
A
2. Metals are a better electrical conductor than glasses because metals: A. Have more total electrons per volume B. Have more conducting electrons per volume C. Have electrons which move faster D. Have electrons which move slower
B
22. The families of slip plane and slip direction in the fcc structures such as those for Cu, Al, Ni, Ag, Au, are {111} and <110> respectively. Consequently, the number of slip systems in the fcc structure is A. 24 B. 12 C. 3 D. 6
B
28 Above( in Figure 4) is a plot of engineering stress and strain obtained at the beginning of a tensile test of 0.2%C plain carbon steel. The tensile modulus of this steel is closest in value to A. 360 GPa B. 180 GPa C. 180 GN D. 360 GN
B
29 When a cold-worked metal is heated into the temperature range where recovery takes place, how are the following affected, the metal ductility is usually significantly A. Decreased B. Increased C. Changed D. Stable
B
30. A cylindrical specimen of a silicon alloy, 8 mm in diameter is stressed elastically in tension. A force of 15,700 N produces a reduction in specimen diameter of 5x10-3 mm. Compute the Poisson's ratio for this material if its modulus of elasticity, E, is 140 GPa. A. 0.18 B. 0.28 C. 0.38 D. 0.48
B
31. One factor which does not lead to scatter in measured material mechanical properties is: A. Operator bias B. Low mechanical strength C. Apparatus calibration D. Material inhomogeneities
B
33. If you increase the rate of deformation in tensile testing of materials, the: A. Tensile strength decreases B. Tensile strength increases C. Elongation increases D. Modulus of elasticity decreases
B
36. The tensile test of a viscoelastic material was stopped when the stress was 160 MPa. In 60seconds, the stress decreased to 100 MPa. The relaxation time of the material is approximately: A. 28 seconds B. 128 seconds C. 318 seconds D. 518 seconds
B
38. Recrystallization of a metal can be described as: A. The formation of coarse grains by the motion slip planes. B. The formation of fine grains by the motion and alignment of dislocations. C. The formation of many different size grains by the motion and alignment of dislocations. D. The formation of coarse grains by the motion and alignment of slip planes
B
38. Thermal toughening is achieved by: A. Creating tensile stresses in the surface layer of glasses B. Creating compressive stresses in the surface layer in the surface layer C. Changing thermal properties of glasses D. Changing chemical composition of glasses
B
42. Critical fibre length does not depend upon one of the following, ie: A. Properties of fibres B. Volume fraction of fibres C. Properties of matrix D. Strength of the adhesion between fibres and matrix
B
43. What is one reason concrete is mixed with more water then it is necessary for hydration reactions? A. To improve concrete mechanical properties B. To cut the cost of concrete C. To give concrete sufficient workability D. To increase concrete durability.
B
45. The tensile test of a viscoelastic material is stopped when stress was160 MPa in 20s stress becomes 100 MPa. The relaxation time of the material is approximately: A. 17.5s B. 42.5s C. 111.5s D. 338.5s
B
48. Which type of deformation is irreversible? A. Elastic deformation B. Viscous flow C. Viscoelastic deformation D. Non-linear elastic deformation
B
50. If you decrease the rate of deformation in tensile testing of thermoplastics, A. Tensile strength increases B. Tensile strength decreases C. Elongation decreases D. Modulus of elasticity increases
B
50. We can improve the sustainability of a product during the design phase by doing all of the followings except: A. increase the use of recycled materials B. increase the use of composite materials C. increase the use of homogenous materials D. extend product life
B
60. A Supercooled liquid is: A. A Metal below melting point B. An Amorphous ceramic above glass transition temperature C. An Amorphous thermoplastic below glass transition temperature D. A Crystalline ceramic above melting point
B
8. Metallic solids are held together by A. The attraction between ion cores B. The attraction between ion cores and the electrons C. Electrons shared between adjacent pairs of atoms D. The attraction between electrons in adjacent pairs of atoms
B
8. The amount of a unit cell occupied by atoms as opposed to the amount of void space can be identified by A. The lattice parameter. B The Atomic Packing Factor. C. Density. D. Coordination number.
B
The Critical fibre length of a fibre reinforced composite material, does not depend upon: A. Strength of fibres B. Volume fraction of fibres C. Fibers diameter D. Strength of the adhesion between fibres and matrix
B
We can improve the sustainability of a product during the design phase by doing all of the followings except: A. increase the use of recycled materials B. increase the use of composite materials C. increase the use of homogenous materials D. extend product life
B
1. The melting points of most plastics are lower than most metals because: A. Covalent bonds are weaker than metallic bonds B. Ionic bonds are weaker than metallic bonds C. Van der Waals bonds are weaker than metallic bonds D. Van der Waals bonds are weaker than covalent bonds
C
11. Most engineering metals can deform at a much lower yield strength than the theoretical yield strength because A. vacancies in polycrystalline materials will cluster together under the applied stress causing the materials to yield It can be extended by more than 100% B. all engineering materials possess a granular structure allowing the grains to slide past one another C. .all engineering materials usually contain dislocations which are mobile under applied stresses D. the Young's modulus of engineering metals is much lower than that of ideal materials
C
12. Van der Waals bonding is a result of A. Attraction between magnetic dipoles B. Attraction between saturated covalent bonds C. Attraction between electrostatic dipoles D. Attraction between ionic bonds
C
13. The electronegativity of an element is a measure of A. The excess of electrons over protons B. The number of electrons in the valence shell C. The strength with which electrons are attracted to the atom D. The potential difference between the electrons and protons
C
14. Concrete is mixed with more water then is necessary for hydration reactions: A. To improve concrete mechanical properties B. To cut the cost of concrete C. To give concrete sufficient workability D. To increase concrete durability.
C
15. Structural steel yields plastically well below its theoretical strength (i.e. about E/15) because A. it contains alloy elements as precipitates B. contains alloy elements in solution C. it contains dislocations D. it contains vacancies
C
17. In a cubic crystal structure the slip system comprising the [111] direction and the (111) plane are A. Not related B. At 45 degrees to each other C. At right angles to each other D. Parallel to each other
C
20. For the hexagonal close packed crystal structure, the atomic packing factor is? A. The same as for a simple cubic structure B. The same as for a body centred cubic structure C. The same as for a face centred cubic structure D. Not able to be determined
C
24. A cylindrical tensile sample has a modulus of 200 GPa and a yield stress of 1000 MPa. The Poisson's ratio of the sample is ν = 0.30. If the sample's initial dimensions are length 1 metre and radius 1 cm, the change in radius of the specimen when it is uniaxially stretched precisely to the yield point is about a A. 0.15 mm decrease B. 0.15 mm increase C. 0.015 mm decrease D. 0.015 mm increase
C
26 A 70% Cu-30% Zn brass sheet is 0.0955 cm thick and is cold-rolled with a 30 percent reduction in thickness. The final thickness of the sheet is determined as closest in value to A. 0.035 cm B. 0.139 cm C. 0.0669 cm D. 37.500 cm
C
29. A 50 mm cylindrical bar of aluminium 20 mm in diameter is to be deformed elastically by application of force along the bar axis. Determine the force (approximately) which will produce an elastic elongation of 7.5x10-3 mm, where the material's Modulus of Elasticity is 70 GPa. A. 110 N B. 330 N C. 3300 N D. 11000 N
C
3. Pauli's exclusion principle states that, within one atom A. No more than two electrons may have the same energy B. The spins of the electrons interact so as to become parallel if possible C. No two electrons may have the same four quantum numbers D. There are only two values for the quantum numbers
C
32. A concrete column is supported by a series of square steel rods. Determine the dimension, w, of one of the square sides of the rod, if the load on each rod is 60.5 kN. Assume a factor of the safety is 2, and a yield strength of 1000 MPa. A. 0.11 mm B. 1.1 mm C. 11 mm D. 110 mm
C
33. A fatigue test is made with a maximum stress of 172 MPa and a minimum stress of -27.6 MPa. The mean stress is closest in value to A. 199.8 MPa B. 99.9 MPa C. 72.3 MPa D. -0.16 MPa
C
35. Semicrystalline thermoplastics differ from thermosets in that: A. Thermoplastics have better mechanical properties B. Have glass transition temperature C. Have melting temperature D. They exhibit visco-elastic behavior.
C
39. Relaxation of stresses cannot be described by the following model: A. Maxwell model B. Generalized Maxwell model C. Voight-Kelvin model D. The combination of Maxwell and Voight-Kelvin model
C
39. The elastic strain obtained on applying a stress to an anelastic material is: A. Time dependent B. Partially permanent C. Non-linearly Proportional to stress D. Inversely proportional to stress
C
4. Materials selection decision must include materials considerations of ease of recovery and recycling. However, there are a number of impediments including A. The high collection and manufacturing cost B. The high distribution and selling cost C. Difficulties in separating components made from mixed materials D. Difficulties in manufacturing recycling materials
C
4. Semicrystalline thermoplastics differ from amorphous thermoplastics in that: A. Semicrystalline thermoplastics have better mechanical properties B. Have glass transition temperature C. Have melting temperature D. They exhibit visco-elastic behaviour.
C
42. For a small anode to cathode ratio, the corrosion rate will be higher than for a large anode to cathode ratio; A. but will try and remain the same B. this is a false statement C. this is a true statement D. and will be influenced by the environment
C
43. Cold worked metals are more susceptible to corrosion than hot worked metals because of A. the decreased dislocation density B. increased slip systems C. the increased dislocation density D. decreased slip systems
C
44 In the prevention of corrosion Tin offers protection to steel in tin cans by the process know as: A. anodic protection B. cathodic protection C. galvanic protection D. sacrificial protection
C
46. A Supercooled liquid is: A. Semicrystalline plastic above melting point B. Amorphous plastic above Tg C. Amorphous ceramic above Tg D. Amorphous ceramic below T
C
46. Running the same test under the same conditions, the tensile stress in 100s will be close to: A. 0.5 MPa B. 1.5 MPa C. 15 MPa D. 75 MPa
C
49. When compared to isotropic plastics fibers show; A. Lower Modulus of Elasticity B. Lower Tensile Strength C. Higher Tensile strength D. No difference
C
5. The material selection process involves many aspects of materials properties. manufacturability, cost and being able to: A. prevent waste B. conserve and improve the ecosystem C. look for opportunities to recycle or reuse existing materials D. cultivate engineering solutions beyond the current approaches
C
52. The relaxation of stresses in thermoplastics can't be described with the following model(s): A. Maxwell model B. Generalized Maxwell model C. Voight-Kelvin Model D. The combination of Maxwell and Voight-Kelvin models
C
53. With the increase of solid ceramic particles volume fraction in polymeric matrix: A. Elongation at break will be higher B. Modulus of elasticity will be lower C. Modulus of elasticity will be higher D. Nothing will happen
C
6. Creep of plastics can be described best with the following model: A. Maxwell model B. Generalized Maxwell model C. Voight-Kelvin model D. Ideal elastic model
C
7. With the increase of crystallinity of semicrystalline thermoplastics: A. Elastic modulus decreases B. Tensile strength decreases C. Elongation decreases D. All above
C
8. Thermal tempering of glasses is achieved by: A. Creating tensile stresses in the surface layer of glasses B. Changing thermal properties of glasses. C. Creating compressive stresses in the surface layer. D. Changing chemical composition of glasses.
C
9. The yield strength of mild steel with an average grain size of 0.05 mm is 138 MPa. We know, using the Hall Petch relation that σ0 is 55.5MPa and the value of the Hall-Petch constant k =18.43MPa mm1/2. For a yield strength of 207 MPa, the grain size of the mild steel will be approximately: A. 0.0196 mm B. 0.0074 mm C. 0.0148 mm D. 0.0022 mm
C
13. Which test is used to measure fracture toughness of materials? A. Tensile test B. Compressive test C. Three point bending D. Four point bending.
D
2. When selecting materials for lightweight design, two properties are of importance for comparison. These properties are essentially: A. Strength and weight B. Stiffness and weight C. Strain and density D. Strength and density
D
25. Calculate the percent cold reduction after cold rolling 1.016 mm-thick aluminum sheet to 0.635mm is closest in value to A. 38.10% B. 18.75% C. 75.00% D 37.50%.
D
3. When classifying processes and materials for the manufacture of components, the choice of process is based on a number of factors which involve: A. Material only B. The number of parts to be made C. The shape, dimension and precision of the component D. All of the above
D
3. Which of the following materials are polymers: A. Human skin B. Vinyl car seat C. Tree limb D. All of the above
D
31. The three sequential stages of the brittle failure of a metal may be described as A. microcracks are nucleated, dislocations become concentrated along slip planes and microcracks propagate as a result of further increases in shear stress. B. dislocations become concentrated along slip planes, microcracks propagate as a result of further increases in shear stress and microcracks are nucleated. C. dislocations become concentrated along slip planes, microcracks are nucleated and Stored elastic strain energy can also contribute to the propagation. D. dislocations become concentrated along slip planes, microcracks are nucleated and microcracks propagate as a result of further increases in shear stress
D
36. The critical resolved shear stress for slip in a single crystal of pure zinc is 1.8 x 105 Pa. The angle between the tensile axis and the slip direction is 85°; and the angle between the tensile axis and the normal to the slip plane is 15°. The magnitude of the tensile stress necessary to initiate slip is then is closest in value to A. 4.28 MPa B. 1.07 MPa C. 8.56 MPa D. 2.14 MPa
D
37. The effect of annealing on the microstructure of a metal : A. Cause an increase in the dislocation density and an increase in grain size. B. Cause an increase in the dislocation density and an decrease in grain size. C. Cause a reduction in the dislocation density and a reduction in grain size D. Cause a reduction in the dislocation density and an increase in grain size
D
4. The characteristic feature of the transition elements is A. A partly filled valence subshell B. An empty inner subshell C. An unfilled outer subshell D. A partly filled subshell
D
40. If Poisson's ratio during elastic deformation under uniaxial tensile stress is less than 0.5: A. There is an expansion in each of the two lateral directions B. There is a decrease in specimen volume C. There is an increase in specimen volume D. There is a no change in specimen volume
D
40. Mechanical properties of fibre reinforced composites depend upon A. Volume fraction of fibers B. Fibers mechanical properties C. Matrix mechanical properties D. All of the above
D
45. Which test is used to measure fracture toughness? A. Tensile test B. Compressive test C. Three point bending D. Four point bending.
D
47. Relaxation of stresses are typical for: A. Elastic materials B. Non-linear elastic materials C. Viscous liquids D. Viscoelastic materials
D
47. Which of the following is not a greenhouse gas? A. methane (CH4) B. nitrous oxide (N2O) C. sulphur hexafluoride (SF6) D.sulphur dioxide (SO2)
D
48. The environmental loads of a product considered in life cycle assessment exclude A. methane emission B. sulphur dioxide emission C. embodied energy D. recyclability
D
5. Which material has the highest fracture toughness? A. Diamond B. Polypropylene C. Glass (Pyrex) D. Steel
D
51. Thermoplastics differ from thermosets in that: A. Thermoplastics have higher strength B. Thermoplastics can be used as a matrix for composite materials C. Thermoplastics can exhibit visco-elastic behavior. D. Thermoplastics can be melted
D
54. Critical fibre length depend upon: A. Shear strength of fibre matrix interface B. Fibre tensile strength C. Fibre diameter D. All of them
D
59. Thermal toughening of glass is achieved by: A. Changing chemical composition of glasses B. Creating tensile stresses in the surface layer C. Healing surface defects. D. Creating compressive stresses in the surface layer
D
6. Dislocations may be considered as bends, waves or an extra half plane in A. Polymers. B. Ceramics. C. Composites. D. Metals.
D
6. Ionic bonding is a result of the A. Sharing of electrons of two atoms B. Donation of electrons of two atoms C. Acceptance of electrons of two atoms D. Donation and acceptance of electrons of two atoms
D
9. Mechanical properties of composites depend upon A. Volume fraction of fillers B. Fillers mechanical properties C. Matrix mechanical properties D. All of them
D
An estimate of the tensile strength of concrete is determined by: A. Tensile testing B. Compressive testing C. Three point bending D. Four point bending
D
The environmental loads of a product considered in life cycle assessment exclude A. methane emission B. sulphur dioxide emission C. embodied energy D. recyclability
D
Which of the following is not a greenhouse gas? A. methane (CH4) B. nitrous oxide (N2O) C. sulphur hexafluoride (SF6) D. sulphur dioxide (SO2)
D
