Materials Science 10 Things Every Engineer Should Know Answer Of Coursera Quiz. In this post you will get Correct Quiz Answer of Materials Science 10 Things Every Engineer Should Know

 

Materials Science 10 Things Every Engineer Should Know Answer

Offered By ”University of California”

Enroll Now

N.B. We attempted our best to keep this site refreshed for our clients for nothing. You can likewise contribute by refreshing new inquiries or existing inquiry answer(s). There are numerous inquiries on our site, it is difficult for us to check them consistently. It will be extraordinary on the off chance that you can assist us with updating the site. Just let us know if you find any new questions through mail or comment . We will attempt to refresh the inquiry/answer ASAP.

Thing 1

1.
Question 1
The first three categories introduced in this segment (metals, polymers,
and ceramics) are based on the three types of primary bonding: metallic, ________, and ionic, respectively.

1 point

  • secondary
  • covalent
  • van der Waals

2.
Question 2
Glasses are considered a category separate from ceramics because their
chemistry is different, even though their atomic structure is the same.

1 point

  • True
  • False

3.
Question 3
Fiberglass is a good example of a ___________ combining the strength and stiffness of reinforcing glass fibers with the ductility of the polymeric matrix.

1 point

  • composite
  • semiconductor
  • ceramic

4.
Question 4

 

Semiconductors are considered a category separate from
metals because their electrical conductivity is different.

1 point

  • True
  • False

5.
Question 5
The relationship between atomic bonding and the elastic modulus or stiffness of a metal is an example of how structure (atomic-level in this case) leads to _____________.

1 point

  • properties
  • breakage
  • permanent deformation

 

 

 

Thing 2

 

1.
Question 1
Aluminum metal is an example of a ______________.

1 point

body-centered cubic crystal structure

face-centered cubic crystal structure

simple cubic crystal structure

2.
Question 2
The vacancy and the interstitial are two common types of point defects in metallic crystal structures.

1 point

True

False

3.
Question 3
The Arrhenius relationship shows that the rate of chemical reactions increases _______________ temperature.

1 point

with the fourth power of

linearly with

exponentially with

4.
Question 4
The Arrhenius plot is a linear set of data points in which the logarithm of rate is plotted against the ____________.

1 point

temperature in °C

inverse temperature in K-1

absolute temperature in K

5.
Question 5
The activation energy, Q, for a chemical
reaction is indicated by the _______________ of the Arrhenius plot.

1 point

slope

intercept at 1/T = 1

intercept at 1/T = 0

6.
Question 6
The gas constant, R, is equal to _______________ times the Boltzmann’s constant, k.

1 point

Avogadro’s number

1024

10-24

7.
Question 7
The gas constant, R, is an appropriate
term for equations describing gas phases and ________________ processes.

1 point

no other

all other

solid-state

8.
Question 8
The energy needed to produce a single
vacancy, Ev, is the same as the activation energy, Q.

1 point

True

False

9.
Question 9
Solid-state diffusion occurs in the face
centered cubic structure of aluminum by individual aluminum atoms hopping into
_______________ sites.

1 point

adjacent interstitial

adjacent occupied

adjacent vacant

10.
Question 10
As an indication of how “close packed” the aluminum (FCC) crystal structure is, ________ of the volume of the unit cell is occupied by the aluminum atoms.

1 point

74%

68%

70%

11.
Question 11
The diffusion coefficient is defined by _______________.

1 point

Fick’s third law

Fick’s first law

Fick’s second law

12.
Question 12
The diffusivity (D) of copper in a brass alloy is 10-20 m2/s
at 400 °C. The activation energy for copper diffusion in this system is 195
kJ/mol. The diffusivity at 600 °C is _____________.

1 point

2.93 x 10-16 m2/s

5.86 x 10-17 m2/s

2.93 x 10-17 m2/s

 

 

 

Thing 3

 

1.
Question 1
An edge dislocation corresponds to an extra ______________.

1 point

half-plane of atoms

full plane of atoms

cluster of atoms

2.
Question 2

An edge dislocation is a linear defect with the
Burgers vector _______________ to the dislocation line.

1 point

perpendicular

at a 45 degree angle

parallel

3.
Question 3
Crushing an empty soda can made of aluminum alloy is an example of ______________.

1 point

viscous deformation

elastic deformation

plastic deformation

4.
Question 4
Plastic deformation by dislocation
motion is a ___________ alternative to deforming a defect-free crystal
structure.

1 point

stress-free

low-stress

high-stress

 

 

 

Thing 4

 

1.
Question 1
The first of the “big four” mechanical
properties obtained in the tensile test is ___________________.

1 point

tensile strength

elastic modulus

yield strength

2.
Question 2
The tensile strength is ___________ the
yield strength for typical metal alloys.

1 point

less than

greater than

about the same as

3.
Question 3
The ductility corresponds to the ______________.

1 point

strain at failure

total amount of elastic deformation

strength at failure

4.
Question 4
The Elastic Modulus is given by ______________.

1 point

Ohm’s Law

Poisson’s ratio

Hooke’s Law

5.
Question 5
The yield strength corresponds to ______________.

1 point

the point of tangency where plastic deformation first begins

an offset of 0.2%

an offset of 0.1%

6.
Question 6
The stress versus strain curve shows that a metal alloy becomes weaker beyond the tensile strength.

1 point

True

False

7.
Question 7
The elastic “snap back” that occurs at failure is parallel to ______________.

1 point

the strain axis

the stress axis

the elastic deformation portion of the stress-strain curve.

8.
Question 8
The Toughness or work-to-fracture is the total area under the stress versus strain curve.

1 point

True

False

 

 

 

 

Thing 5

 

1.
Question 1
“Creep” deformation describes the
behavior of materials being used at high temperatures under high pressures over
_____________ time periods.

1 point

long

short

intermediate

2.
Question 2
We added comments about polymers because their weak, secondary bonding between long chain molecules causes them to exhibit creep deformation at relatively low temperatures.

1 point

True

False

3.
Question 3
In the simplest sense, the creep test is
essentially a tensile test done at a high temperature under ____________ load.

1 point

no

a variable

a fixed

4.
Question 4
A linear portion of the strain versus time plot corresponds to the ______________ stage of the overall creep curve.

1 point

secondary

tertiary

primary

5.
Question 5
The strain rate in the ______________ stage of the creep test is analyzed using the Arrhenius equation, analogous to our previous discussion of the diffusion coefficient.

1 point

tertiary

primary

secondary

6.
Question 6
A powerful use of the Arrhenius relationship is to measure creep data at low temperatures and then extrapolate the data to high temperatures, allowing us to predict the performance there.

1 point

True

False

7.
Question 7
In a laboratory creep experiment at
1,000 °C, a steady-state creep rate of 5 x 10-1 % per hour is
obtained for a metal alloy. The activation for creep in this system is known to
be 200 kJ/mol. We can then predict that the creep rate at a service temperature
of 600 °C will be ______________. (We can assume the stress on the sample in
the laboratory experiment is the same as at the service temperature.)

1 point

4.34 x 10-5 % per hour

80.5 x 106 % per hour

8.68 x 10-5 % per hour

8.
Question 8
For high temperature creep deformation in ceramic materials, a common mechanism is ______________.

1 point

dislocation climb

viscous flow (molecules sliding past one another)

grain boundary sliding

 

 

Thing 6

1.
Question 1
The ductile-to-brittle transition was first discovered in conjunction with the failure of ______________.

1 point

the Queen Mary

the Titanic

Liberty Ships

2.
Question 2
The impact energy is an indicator of
whether a fracture is ductile or brittle, as measured by the ____________ test.

1 point

creep

Charpy

tensile

3.
Question 3
Although they have equally high atomic
packing densities, face-centered cubic (fcc) metals with more slip systems are
typically ductile while hexagonal close packed (hcp) metals are relatively __________.

1 point

strong

brittle

weak

4.
Question 4
Body-centered cubic (bcc) alloys such as
low-carbon steels demonstrate the ductile-to-brittle transition because their
dislocation motion tends to be ___________ than that in the more densely packed
fcc alloys.

1 point

faster

slower

more erratic

 

 

 

Thing 7

 

1.
Question 1
We focus on “critical flaws” that ______________.

1 point

lead to catastrophic failure

are larger than 1 mm in size

are larger than 1 μm in size

2.
Question 2
We use the example of __________________
to illustrate concern about a famous “critical flaw.”

1 point

Liberty Ships

the Liberty Bell

the Hindenburg

3.
Question 3
The design plot is composed of two intersecting segments: yield strength corresponding to general yielding and fracture toughness corresponding to ______________.

1 point

fracture following multiple stress applications

high-temperature fracture

flaw-induced fracture

4.
Question 4
The design plot shows stress as a function of time.

1 point

True

False

5.
Question 5
The ______________ flaw size is defined
within the design plot at the intersection between the general yielding segment
and the flaw-induced fracture segment.

1 point

critical

maximum

minimum

6.
Question 6
The I in the subscript of the
fracture toughness, KIc , refers to ______________ .

1 point

mode I (uniaxial tensile) loading

the primary stage of creep deformation

“i” for incremental loading

7.
Question 7
The stress versus strain curve for a sample with a critical pre-existing
flaw looks like ______________.

1 point

a regular stress versus strain curve but with a lower value of Y.S.

that of a brittle ceramic

a regular stress versus strain curve but with a higher value of Y.S.

8.
Question 8
The benefit of failure by general yielding is that ______________.

1 point

the failure occurs quickly

the plastic deformation serves as an early warning

the structure does not deform permanently

9.
Question 9
“Flaw-induced fracture” is also known as “catastrophic fast fracture.”

1 point

True

False

 

 

 

Thing 8

 

1.
Question 1
The fatigue strength that is associated with catastrophic failure after
a large number of stress cycles is ______________ the yield strength.

1 point

less than

greater than

about the same value as

2.
Question 2
A metal alloy known to have good
ductility is used in the manufacture of a spring in a garage door assembly. The
spring breaks catastrophically in its first use, under a load known to
correspond to about 2/3 of the alloy’s yield strength. This is a good example
of fatigue failure.

1 point

True

False

3.
Question 3
The fatigue curve is a plot of breaking stress versus ______________.

1 point

the number of stress cycles

time

temperature

4.
Question 4

The “fatigue strength” is defined as the point where
the fatigue curve reaches a value of roughly _____________ of the tensile
strength.

1 point

10%

75%

one-fourth to one-half

5.
Question 5
Fatigue is the result of a critical flaw built up ______________.

1 point

instantly

prior to being put into service

after a large number of stress cycles

6.
Question 6
The relationship of fatigue to the
design plot (introduced in our discussion of fracture toughness) is that we
grow the size of a flaw at a relatively low stress until the flaw size reaches
the “flaw-induced fracture” segment of the design plot.

1 point

True

False

 

 

 

Thing 9

 

1.
Question 1
We begin by focusing on making things
slowly. Phase diagrams are maps that help us track microstructural development
during the slow cooling of an alloy. The Sn-Bi phase diagram is an example of a
______________ diagram.

1 point

temperature versus time

eutectoid

eutectic

2.
Question 2
The phases in a two-phase
region of the phase diagram are determined by the adjacent, single phases on
either side of that two-phase region.

1 point

True

False

3.
Question 3
In the important Fe – Fe3C
(iron carbide) phase diagram, steel making is described by slow cooling through
the ______________ reaction.

1 point

melting

eutectic

eutectoid

4.
Question 4
The “pasty” quality of lead solders in the lead-tin system can be
attributed to ______________.

1 point

the fact that lead has a higher melting point than tin

the nature of the two-phase liquid + α solid solution region

the nature of the two-phase α solid solution + β solid solution
region

5.
Question 5
Heat treatment can be
defined as the time-independent process of producing a desired microstructure.

1 point

True

False

6.
Question 6
Previously (in Thing 2), we saw that diffusion increases as temperature
increases. Instability ______________ as temperature decreases.

1 point

decreases

stays about the same

increases

7.
Question 7
Because of the competition between instability and diffusion, the most rapid
transformation will occur _______________.

1 point

above the transformation temperature

at the transformation temperature

below the transformation temperature

8.
Question 8

The “knee-shaped” curve of the TTT diagram for
eutectoid steel is a good example of the competition between instability and ______________.

1 point

radioactivity

diffusion

stability

9.
Question 9
As we monitor the TTT diagram for
eutectoid steel through the diffusional transformation region, we see that the
decreasing magnitude of diffusivity with decreasing temperature leads to
______________.

1 point

increasingly finer microstructures

increasingly more coarse microstructures

generally unchanged grain sizes

10.
Question 10
As we continue to go to lower temperatures in the TTT diagram for
eutectoid steel, the diffusionless transformation to form martensite is the
result of ______________.

1 point

increasingly rapid atomic mobility

the domination of instability

freezing temperatures

 

 

 

 

Thing 10

 

1.
Question 1
The discovery of the electron in 1897 was followed by the invention of
the transistor in _________.

1 point

1937

1947

1957

2.
Question 2
Since the development of the integrated circuit in 1971, Moore’s Law has
correctly predicted that the number of transistors on a semiconductor “chip”
should double about every ____ years.

1 point

four

two

five

3.
Question 3
Electronic conduction in a semiconductor is the result of the promotion
of an electron from the conduction band up to the valence band.

1 point

True

False

4.
Question 4
The “2” that appears in the exponent of the Arrhenius equation for an
intrinsic semiconductor is ______________.

1 point

derived from the fact that each electron promotion produces two carriers – an electron and an electron hole (in the valence band)

a typographical error

derived from the ideal gas law

5.
Question 5
An extrinsic semiconductor is one
with a small amount of purposefully added impurity or “dopant.”

1 point

True

False

6.
Question 6
The slope of the Arrhenius plot for an
extrinsic semiconductor is ______________ that for the corresponding pure or
undoped material.

1 point

greater than

less than

about the same

7.
Question 7
Combining the extrinsic behavior with the intrinsic on the Arrhenius
plot produces ______________.

1 point

no effect, given the different nature of conductivity in the two
cases

a stable level of conductivity over a range of temperatures

a doubling of the conductivity

 

 

 

Ten Things Final

 

1.
Question 1
The first three categories introduced in
the opening of the course (metals, polymers, and ceramics) are based on the
three types of primary bonding: metallic, covalent, and ____________,
respectively.

1 point

hydrogen

van der Waals

ionic

2.
Question 2
In illustrating the relationship between
atomic structure and the elastic modulus or stiffness of a metal (structure
leads to properties!), we saw how elastic deformation follows from the
stretching of atomic ___________.

1 point

bonds

weights

energy

3.
Question 3

The _________ plot is a linear set of data points in
which the logarithm of rate is plotted against the inverse of absolute
temperature in K-1.

1 point

Arrhenius

fatigue

TTT

4.
Question 4
In the face centered cubic
structure of aluminum, solid-state diffusion occurs by individual aluminum
atoms hopping into adjacent interstitial sites.

1 point

True

False

5.
Question 5

___________________ is a linear defect with the
Burgers vector perpendicular to the dislocation line.

 

1 point

A vacancy

An edge dislocation

An interstitial

6.
Question 6
Consider the body of an automobile made
of steel. A small dent in that structure when the automobile is accidentally
driven into a barrier is an example of _________ deformation.

1 point

plastic

elastic

viscous

7.
Question 7
In the tensile test, the yield strength
(Y.S.) is found just beyond the linear elastic region (which gives the elastic
modulus, E) at an offset of 0.2%
strain.

1 point

True

False

8.
Question 8
Beyond the tensile strength (T.S.), the
maximum stress value measured over the range of the tensile test, we measure the
ductility corresponding to the total amount of ______________ deformation.

1 point

elastic

plastic

elastic + plastic

9.
Question 9
For high temperature creep deformation
in metal alloys, a common mechanism that we illustrated is ______________.

1 point

grain boundary sliding

viscous flow (molecules sliding past one another)

dislocation climb

10.
Question 10

A powerful use of the Arrhenius relationship is to
measure creep data at high temperatures over conveniently short time periods
and then extrapolate the data to __________ temperatures, allowing us to
predict the performance of the material over long operating times.

1 point

low

cryogenic

even higher

11.
Question 11
The impact energy is the standard property for monitoring the ductile-to-brittle transition. The impact energy is commonly measured by means of the ______________.

1 point

tensile test

creep test

Charpy test

12.
Question 12
Body-centered cubic (bcc) alloys tend to
exhibit the ductile-to-brittle transition because they have fewer slip systems
than in the ductile face-centered cubic (fcc) alloys.

1 point

True

False

13.
Question 13
The design plot is composed of two
intersecting segments: yield strength corresponding to ___________ and fracture
toughness corresponding to flaw-induced fracture.

1 point

high-temperature fracture

general yielding

fracture following multiple stress applications

14.
Question 14
The design plot monitors stress as a function of ______________.

1 point

time

flaw size, a.

strain

15.
Question 15
A metal alloy known to have good
ductility is used in the manufacture of a spring in a garage door assembly. The
spring breaks catastrophically after 10 years of regular use, under a load known
to correspond to about one half of the alloy’s yield strength. This is a good
example of fatigue failure.

1 point

True

False

16.
Question 16
The relationship of fatigue to the design
plot (introduced in our discussion of fracture toughness) is that we grow the
size of a flaw at a relatively low stress until the flaw size reaches the ______________
segment of the design plot.

1 point

yield stress

general yielding

flaw-induced fracture

17.
Question 17

Phase diagrams are maps that help us track
microstructural development during the slow cooling of an alloy. The Fe-Fe3C
(iron carbide) phase diagram is an example of a ______________ diagram, with
special relevance to steelmaking.

1 point

eutectoid

eutectic

temperature versus time

18.
Question 18
Quenching a eutectoid steel below about 200
°C initiates the formation of martensite because the _______________ the
austenite phase has become too great.

1 point

diffusion of carbon within

instability of

specific volume of

19.
Question 19
Electronic conduction in an _____________
semiconductor is the result of the promotion of an electron from the valence
band up to the conduction band across an energy band gap.

1 point

extrinsic

eccentric

intrinsic

20.
Question 20
Combining the extrinsic behavior with
the intrinsic on the Arrhenius plot produces a stable level of conductivity at ______________
temperatures.

1 point

relatively low

relatively high

intermediate

 

 

 

By JAMD Bokhtier

This is JAMD Bokhtier's website.He is a passionate Marketer who dreams,talks,learns and teaches all about Marketing,the owner & the founder of "Life Style Consultant", a specialist in "Digital Marketing" and a Sophophilic.

error: Content is protected !!