Which of the following are common characteristics of thermosetpolymers?
Group of answer choices
None of the these.
Linear or slightly branched long chain molecules.
Soften on heating and harden on cooling.
Heavily networked or cross linked structures.
Which of the following statements is a TRUE statement?
Group of answer choices
Higher molecular weight of a polymer will always have superiorproperties.
Crystallization is not affected by the molecular weight of thepolymer.
Elastomers have very long chains with a high degree of crosslinking.
Crystalline polymers are optically transparent.
The resistance of a metal, R, is defined by theequation of R = Ï l A where A is cross-sectional area,l is length, and Ï is resistivity. How would youcategorize resistance?
Resistance is a __________.
Group of answer choices
Process
Property
Structure
Performance
Other
The addition of a boron (B) impurity tootherwise pure silicon (Si) will:
(Pick all correct answers)
Group of answer choices
Decrease conductivity due to additional scattering of electronsdue to the impurity
Create an additional allowable energy level inside the band-gapcalled an acceptor level
Create an extrinsic semiconductor with the majority chargecarrier being a hole instead of an electron
The casting process is preferred for processing brittlemetals.
Group of answer choices
True
False
Normalizing process transforms deformed large grains intosmaller grains.
Group of answer choices
True
False
Titanium alloys have higher strength and density than steelalloys.
Group of answer choices
True
False
MgO and FeO have an NaCl structure.
Group of answer choices
True
False
