EIT Materials Science

Question 1

What is the coordination number for an atom in a face-centered cubic (FCC) crystal structure?

Accepted Answer

12

Answer

6

Answer

8

Answer

14

Question 2

Which of the following crystal structures has the highest atomic packing factor (APF)?

Accepted Answer

Face-centered cubic (FCC)

Answer

Simple cubic (SC)

Answer

Body-centered cubic (BCC)

Answer

Diamond cubic

Question 3

At what temperature does the eutectoid reaction occur in the iron-carbon phase diagram?

Accepted Answer

727°C

Answer

912°C

Answer

1148°C

Answer

1394°C

Question 4

What is the eutectoid composition in the iron-carbon phase diagram?

Accepted Answer

0.76 wt% C

Answer

0.022 wt% C

Answer

2.14 wt% C

Answer

4.30 wt% C

Question 5

What type of point defect involves a missing atom at a lattice site?

Accepted Answer

Vacancy

Answer

Interstitial

Answer

Substitutional impurity

Answer

Edge dislocation

Question 6

Fick's First Law of diffusion states that flux J equals:

Accepted Answer

-D(dC/dx)

Answer

D(dC/dt)

Answer

D(d²C/dx²)

Answer

C/D

Question 7

The primary distinction between steel and cast iron in the Fe-C phase diagram is:

Accepted Answer

Steel contains less than 2.14 wt% C; cast iron contains 2.14–6.70 wt% C

Answer

Steel contains less than 0.76 wt% C; cast iron contains more than 0.76 wt% C

Answer

Steel contains less than 1.0 wt% C; cast iron contains 1.0–4.3 wt% C

Answer

Steel contains less than 4.3 wt% C; cast iron contains more than 4.3 wt% C