Fundamentals of Engineering Materials Science

Question 1

What crystal structure does α-iron (ferrite) have at room temperature?

Accepted Answer

Body-centered cubic (BCC)

Answer

Face-centered cubic (FCC)

Answer

Hexagonal close-packed (HCP)

Answer

Simple cubic

Question 2

Young's modulus (modulus of elasticity) is defined as:

Accepted Answer

The ratio of stress to strain in the elastic region

Answer

The stress at which permanent deformation begins

Answer

The energy absorbed before fracture

Answer

The material's resistance to surface scratching

Question 3

A vacancy (point defect) in a crystal lattice is best described as:

Accepted Answer

An atom missing from its normal lattice position

Answer

An extra atom squeezed between lattice sites

Answer

An atom displaced to an interstitial site leaving its original site empty

Answer

A foreign atom substituting for a host atom

Question 4

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

Accepted Answer

12

Answer

6

Answer

8

Answer

4

Question 5

The Burgers vector of a dislocation represents:

Accepted Answer

The magnitude and direction of the lattice distortion caused by the dislocation

Answer

The direction of crack propagation in brittle fracture

Answer

The critical resolved shear stress for slip

Answer

The angle of misorientation across a grain boundary

Question 6

Which of the following is a thermosetting polymer?

Accepted Answer

Epoxy resin

Answer

Polyethylene

Answer

Polypropylene

Answer

Nylon 6,6

Question 7

Which atomic bonding type is primarily responsible for the high electrical conductivity of metals?

Accepted Answer

Metallic bonding

Answer

Ionic bonding

Answer

Covalent bonding

Answer

Van der Waals bonding