MSE 200 Final Exam Questions and Answers
Which material shows directional bonding?
a. Iron
b. Gold
c. Diamond
d. all of the above - ANS-c. Diamond
Ideally speaking, bonds tend to form between two particles such that they are
separated by a distance where _____ net force is exerted on them, and their
overall energy is ______.
a. positive, maximized
b. a negative, maximized
c. a positive, minimized
d.a positive, minimized
e. zero, maximized
f. zero, minimized - ANS-f. zero, minimized
How are crystalline structures distinguished from amorphous structures?
a. Crystalline structures have larger average bond distances than amorphous
structures.
b. Amorphous structures always have ionic bonding.
c. Crystalline materials always have a cubic unit cell, but the unit cell for
amorphous materials is more complex.
d. Crystalline structures have long-range, periodic ordering that is absent in
amorphous structures. - ANS-d. Crystalline structures have long-range, periodic
ordering that is absent in amorphous structures.
At a particular temperature which of the following processes has the highest
diffusion coefficient?
a. Carbon in BCC iron
b. Carbon in FCC iron
c. Self-diffusion of iron in BCC iron
d. Self-diffusion of iron in FCC iron - ANS-A. Carbon in BCC iron
What is the coordination number of atoms in BCC?
a. 6
b. 8
c. 12
d. 16 - ANS-b. 8
What is the atomic packing factor for an FCC crystal?
a. 0.52
b. 0.68
c. 0.74
, d. 1.00 - ANS-c. 0.74
7. Which plane is a member of the {123} family for a cubic system?
a. (132)
b. (312)
c. (213)
d. All of the above. - ANS-d. All of the above
Which statement regarding the atomic packing factor (APF) is correct for simple
elemental metals:
(SC-Simple Cubic, BCC-Body Centered Cubic, FCC-Face Centered Cubic)
a. APFbcc<APFsc
b. APFbcc> APFfcc
c. APFsc < APFfcc
d. None of the above - ANS-C. APFsc<APFfcc
Pt is FCC and has a density of 21.4 g/cm' and
an atomic mass of 195 g/mol. Select the statements below that are true:
a. The stacking sequence of close-packed planes is ABCABC...
b. The relationship between the atomic radius and the lattice parameter in Pt is 4R
=aV2
c. All the [110] directions are close-packed.
d. Pt exhibits metallic bonding and can be modeled as a hard-sphere structure.
e. All of the above. - ANS-e. All of the above
Which normally occurs faster, interstitial diffusion or vacancy diffusion?
a. cannot be correlated
b. vacancy diffusion
c. both occur at the same rate
d. interstitial diffusion - ANS-d. interstitial diffusion
Which of the following is not a point defect?
a. Vacancies
b. Substitutional impurity atoms
c. Interstitial impurity atoms
d. Dislocations - ANS-d. Dislocation
Which of the following statements regarding diffusion is true?
a. Diffusion is a temperature-independent process
b. Diffusion coefficient depends on the structure and composition of metals
c. Diffusion coefficient is the same for all metals
d. The total mass transfer does not depend on time - ANS-b. Diffusion coefficient
depends on structure and composition of metals
Complete the following statement: The BCC crystal structure...
a. has an APF of 0.52
b. contains nine atoms per unit cell and has an APF of 0.68.
c. contains two atoms per unit cell and in general, this structure is not as closely
Which material shows directional bonding?
a. Iron
b. Gold
c. Diamond
d. all of the above - ANS-c. Diamond
Ideally speaking, bonds tend to form between two particles such that they are
separated by a distance where _____ net force is exerted on them, and their
overall energy is ______.
a. positive, maximized
b. a negative, maximized
c. a positive, minimized
d.a positive, minimized
e. zero, maximized
f. zero, minimized - ANS-f. zero, minimized
How are crystalline structures distinguished from amorphous structures?
a. Crystalline structures have larger average bond distances than amorphous
structures.
b. Amorphous structures always have ionic bonding.
c. Crystalline materials always have a cubic unit cell, but the unit cell for
amorphous materials is more complex.
d. Crystalline structures have long-range, periodic ordering that is absent in
amorphous structures. - ANS-d. Crystalline structures have long-range, periodic
ordering that is absent in amorphous structures.
At a particular temperature which of the following processes has the highest
diffusion coefficient?
a. Carbon in BCC iron
b. Carbon in FCC iron
c. Self-diffusion of iron in BCC iron
d. Self-diffusion of iron in FCC iron - ANS-A. Carbon in BCC iron
What is the coordination number of atoms in BCC?
a. 6
b. 8
c. 12
d. 16 - ANS-b. 8
What is the atomic packing factor for an FCC crystal?
a. 0.52
b. 0.68
c. 0.74
, d. 1.00 - ANS-c. 0.74
7. Which plane is a member of the {123} family for a cubic system?
a. (132)
b. (312)
c. (213)
d. All of the above. - ANS-d. All of the above
Which statement regarding the atomic packing factor (APF) is correct for simple
elemental metals:
(SC-Simple Cubic, BCC-Body Centered Cubic, FCC-Face Centered Cubic)
a. APFbcc<APFsc
b. APFbcc> APFfcc
c. APFsc < APFfcc
d. None of the above - ANS-C. APFsc<APFfcc
Pt is FCC and has a density of 21.4 g/cm' and
an atomic mass of 195 g/mol. Select the statements below that are true:
a. The stacking sequence of close-packed planes is ABCABC...
b. The relationship between the atomic radius and the lattice parameter in Pt is 4R
=aV2
c. All the [110] directions are close-packed.
d. Pt exhibits metallic bonding and can be modeled as a hard-sphere structure.
e. All of the above. - ANS-e. All of the above
Which normally occurs faster, interstitial diffusion or vacancy diffusion?
a. cannot be correlated
b. vacancy diffusion
c. both occur at the same rate
d. interstitial diffusion - ANS-d. interstitial diffusion
Which of the following is not a point defect?
a. Vacancies
b. Substitutional impurity atoms
c. Interstitial impurity atoms
d. Dislocations - ANS-d. Dislocation
Which of the following statements regarding diffusion is true?
a. Diffusion is a temperature-independent process
b. Diffusion coefficient depends on the structure and composition of metals
c. Diffusion coefficient is the same for all metals
d. The total mass transfer does not depend on time - ANS-b. Diffusion coefficient
depends on structure and composition of metals
Complete the following statement: The BCC crystal structure...
a. has an APF of 0.52
b. contains nine atoms per unit cell and has an APF of 0.68.
c. contains two atoms per unit cell and in general, this structure is not as closely
