True/False

Question 1

Covalent Bonds are directional in nature

Answer 1

True

Question 2

FCC crystals have a higher atomic packing factor than BCC crystals

Answer 2

True

Question 3

The resolution of a scanning electron microscope is poorer than that of an optical microscope

Answer 3

False

Question 4

In a crystalline structure, the equilibrium number of vacancies decreases as the temperature increases

Answer 4

False

Question 5

Fick’s first law of diffusion deals with steady state diffusion of one species in another

Answer 5

True

Question 6

Weak atomic bonds are characterized by high thermal expansion coefficients

Answer 6

True

Question 7

In mixed bonding situations, the degree of ionic bonding is inversely related to the difference between the elements

Answer 7

False

Question 8

Grain boundaries are point defects in crystalline structures

Answer 8

False

Question 9

Interstitial diffusion is generally faster than substitutional diffusion

Answer 9

True

Question 10

Even if Bragg’s Law is satisfied, diffraction peaks from certain planes may be missing in diffraction patterns

Answer 10

True

Question 11

Thermoplastic polymers are brittle at temperatures above the ductile-to-brittle transition temperature

Answer 11

False

Question 12

Increasing the yield strength of a metal by cold working results in a decrease in its ductility

Answer 12

True

Question 13

Copolymers consist of two or more smaller chains linked together

Answer 13

True

Question 14

An intergranular fracture happens through the grains

Answer 14

False

Question 15

Elastomers stretch when stress is applied and recover to their original shape when stress is removed

Answer 15

True

Question 16

The toughness of BCC metals decreases ad temperature decreases

Answer 16

True

Question 17

The steady state creep rate of an alloy decreases as the temperature increases

Answer 17

False

Question 18

The ultimate strength of ceramics is different in compression and in tension

Answer 18

True

Question 19

Strains induced by impurity atoms inhibit dislocation motion

Answer 19

True

Question 20

Thermoset polymers reversibly soften and flow when heated or treated with appropriate solvents

Answer 20

False

Question 21

In a binary eutectic system, an alloy with a eutectic composition has the lowest possible melting point within the system

Answer 21

True

Question 22

In eutectoid reactions, a single liquid phase decomposes into two separate solid phases upon cooling

Answer 22

False

Question 23

Pearlite is a microconstituent formed of two solid phases

Answer 23

True

Question 24

Carbon atoms form a substitutional solid in iron

Answer 24

False

Question 25

The addition of alloying elements to a Fe-C system can shift the eutectoid point

Answer 25

True

Question 26

To form only martensite as the end product, the cooling rate from austenite during continuous cooling of steels must be slower than the Critical Cooling Rate

Answer 26

False

Question 27

The hardness of martensite is a function of its carbon content

Answer 27

True

Question 28

The eutectic reaction is an example of a solid state invariant reaction

Answer 28

False

Question 29

Alpha Ferrite is a BCC solid solution of carbon in iron

Answer 29

True

Question 30

For a given carbon content, the hardness of martensite is a function of the rate of cooling during quenching

Answer 30

False