University of Ontario Institute of Technology

ENGR 2220A

Quiz 1:

1)Which statement is true?

1. Ceramics are organic materials
2. Polymers and metals are inorganic materials
3. Polymers are organic materials
4. Ceramics and polymers are organic materials

2. The four material groups that are generally used by engineers in their designs are:

1. Metals, ceramics, fuels and composites
2. Metals, silica products, nylons and composites
3. Metals, ceramics, polymers and composites
4. Metals, ceramics, gasoline and epoxies

3. Important properties of Metals are:

1. Strong and brittle
2. Strong and ductile
3. Hard and non-deformable
4. Stiff and non-deformable

4. Some examples of polymers are:

1. Cotton, Nylon, petroleum, silk and hemp fibers
2. Cotton, Nylon, silk, glass fibers and wool fibers
3. Cotton, Nylon, glass fibers, wool, silk and hemp fibers
4. Cotton, Nylon, silk, polyethylene and PVC

5. Ceramics are:

1. Hard and very tough
2. Hard but not tough
3. Brittle and soft
4. malleable and strong

6. Which statement is true only for composites?

1. Composites are materials containing two or more elements
2. Composites are materials containing two or more distinct phases
3. Composites are materials containing two or more than two variety of fibers

7. Which of the following statements is true?

1. Biomaterials are materials that mainly contain hydrocarbons
2. Biomaterials have their origins in agricultural products only
3. Biomaterials should not produce toxic substances in human body
4. Biomaterials easily degrade when exposed to sun light

8. Properties of Iron can be changed over a very wide range by imparting proper heat treatment

1. True

2. False

9. Properties of materials depend upon their structure and hence do not dependent on the processes undergone during their production

1. True
2. False

10. If a material is squeezed between a vise;

1. it experiences sheer stresses
2. it experiences tensile stresses
3. it experiences compressive stresses

11. If a material is subjected to torsion;

1. it experiences sheer stresses
2. it experiences tensile stresses
3. it experiences compressive stresses

12. If a long bar having a rectangular cross section (a x b) and length l experiences a force F along its length, the normal stress it endures is defined as:

1. F x a^2
2. F/(a x b)
3. F x a x b

d. F/(a^2)

13. If a long bar having a rectangular cross section (a x b) and length l experiences torsion forces along its length, the shear stress “tau” acts on the area:

1. a^2
2. a x l
3. a x b
4. b x l

14. Engineering stress on a body deformed by the application of a force is defined as:

1. Force divided by the actual cross sectional area
2. Force multiplied by the actual cross sectional area
3. Force multiplied by the original cross sectional area
4. Force divided by the original cross sectional area

15. True stress on a body deformed by the application of a force is defined as:

1. Force divided by the actual cross sectional area
2. Force multiplied by the actual cross sectional area
3. Force multiplied by the original cross sectional area
4. Force divided by the original cross sectional area

16. Stresses generated due to the application of hydrostatic pressure (such as body submerged in ocean) are always tensile in nature:

1. True

2. False

17. Units of stress are:

1. kg X m^2
2. dimensionless
3. N/m^2
4. kg x m/s^2

18. Units of strain are:

1. kg X m^2
2. dimensionless
3. kg/m^2
4. kg x m/s^2

19. The relationship between stress and strain is:

1. Stress is directly proportional to strain
2. Stress is inversely proportional to strain
3. Stress is proportional to the square of strain

20. Young's modulus is

1. The slope of the stress-torsion curve
2. Constant of proportionality between shear force and sheer stresses
3. The slope of the stress strain curve

21. Elastic deformation means

1. When the stress is removed the material exhibits a permanent strain of 0.003
2. When the stress is removed the material exhibits a permanent strain of 0.00
3. The material stretches very easily

22. Non-linear stress strain relation ship is generally exhibited by

1. Polymeric materials
2. Metallic materials
3. Composites
4. Ceramics

23. Symbol for sheer modulus is

1. The Greek letter “nu”
2. The letter E
3. The Greek letter “tau”
4. The Letter G

24. Symbol for the modulus of elasticity is

1. The Greek letter “nu”
2. The letter E
3. The Greek letter “tau”
4. The Letter G

25. An example of a material subjected to tensile stresses in all directions along a plane is

1. Stresses acting on the body of a fish under water
2. Stresses acting on a vertical truss of a bridge
3. Stresses acting in the shell of a pressurized cylinder
4. Stresses acting on the surface of a shaft turning the wheel which pulls the ski chair cables

26. Poisson’s ratio is

1. The ratio of applied stress to the resulting strain
2. The ratio of lateral strain to the normal strain
3. The ratio of applied stress to lateral strain
4. The ratio of normal strain to the lateral strain

27. In a unit crystal, 110 represents

1. a point within it
2. a direction in it
3. a plane in it

28. In a unit crystal, [110] represents

1. a point within it
2. a direction in it
3. a plane in it

29. In a unit crystal, (110) represents

1. a point within it
2. a direction in it
3. a plane in it

30. A material is “Amorphous” when:

1. Its structure is not crystalline
2. Its atoms are packed in periodic 3 D arrays
3. Its structure contains numerous defects
4. It forms simple cubic unit cells

31. Atomic Packing Factor is

1. the ratio of number of whole atoms in a unit cell to the total number of atoms that the unit cell intersects
2. the ratio of weight of whole atoms in a unit cell to the weight of total number of atoms that the unit cell intersects
3. the ratio of volume of the atoms in a unit cell to the volume of the unit cell

32. The maximum APF is exhibited by

1. BCC and FCC crystals
2. HCP and FCC crystals
3. BCC and HCP crystals

33. Polymorphism is defined as

1. the property of a material which enables it to form different crystal structure under different conditions
2. the property of a material which enables it to form different crystal sizes under different conditions
3. the property of a material which enables it to form different compositions under different conditions

34. A material is isotropic if it:

1. has uniform composition
2. Exhibits uniform properties in all direction
3. Exhibits different properties in different direction

35. The larger the difference in electro negativity between two atoms, the greater is the tendency to form ionic bonds

1. T
2. F

36. The maximum possible value of APF is:

a. 1

b. 0.84

c. 0.74

d. 0.68

37. Covalent bonds are in general

1. Stronger than ionic bonds
2. Weaker than secondary bonds
3. Non directional in nature
4. Directional in nature

38. Metals tend to have higher densities because

1. The metallic bonds are non directional allowing atoms to be densely packed together.
2. The metallic bonds are directional in nature thereby forming linkages over long atomic distances and forcing atoms to be densely packed together.
3. Metals get covalently bonded to form the heavier structure