Material Science for Chemical Engineering Mid - I, September - 2014

1.The atomic diameter of an BCC crystal (if a is lattice parameter) is
  • a
  • a/2
  • a/(4/√3)
  • a/(4/√2)
Answer: C
2.The minimum number of ions in the unit cell of an ionic crystal with FCC space lattice is
  • 4
  • 8
  • 12
  • 16
Answer: B
3.The number of atoms present in the unit cell of HCP structure is
  • 2.
  • 4.
  • 6.
  • 7.
Answer: C
4.The correct order of the coordination number is SC, BCC, FCC and HCP unit cells is
  • 12, 8, 12, 6.
  • 6, 8, 12, 12.
  • 8, 6, 12, 12.
  • 6, 12, 12, 8.
Answer: B
5.Requirement for cross-slip movement of dislocation
  • Preferred slip plane
  • Preferred slip direction
  • No preferred slip plane
  • No preferred slip direction
Answer: C
6.Not a typical site for nucleation during solid state transformation
  • Container wall
  • Grain boundaries
  • Stacking faults
  • Dislocations
Answer: A
7.Impurity not responsible for temper embrittlement
  • Sn
  • Sb
  • Si
  • As
Answer: C
8.Eutectic product in Fe-C system is called
  • Pearlite
  • Bainite
  • Ledeburite
  • Spheroidite
Answer: C
9.The boundary line between (liquid) and (liquid+solid) regions must be part of ________.
  • Solvus
  • Liquidus
  • Solidus
  • Tie-line
Answer: B
10.In a single compenent condensed system, if degree of freedom is zero, maximum number of phases that can co-exist _________.
  • 0
  • 1
  • 3
  • 2
Answer: D
11.Gibbs phase rule for general system --------------------------------
Answer: P + F = C + 2
12.A solid + a liquid result in a liquid up on heating during ------------------- reaction.
Answer: Peritectic
13.Relative amounts of phases in a region can be deduced using -----------------------
Answer: Lever rule
14.Average frequency of atomic vibrations in a solid (in Hz) -------------------------
Answer: 1013
15.Thermodynamically stable defects are -----------------------
Answer: Point defects
16.Miller indices for Octahedral plane in cubic crystal are -------------------
Answer: (1 1 1)
17.Atomic packing factor is ---------------------
Answer: Volume fraction of atoms in cell
18.Repeatable entity of a crystal structure is known as ------------------
Answer: Unit cell
19.Schottky defect is ---------------------
Answer: purely an interstitial defect
20.The imperfection in the crystal structure of metal is called --------------------
Answer: dislocation