SECTION-5

#### ENGINEERING MATERIAL OBJECTIVE QUESTIONS/MCQ

##### Q41. The atomic packing factor is defined as the

(a) ratio of the volume occupied by the unit-cell to the volumes of the atoms per unit-cell
(b) ratio of the volume of the atoms per unit cell to the total volume occupied by the unit-cell
(c) sum of the volume of the atoms per unit-cell and the total volume occupied by the unit-cell
(d) difference of the volume of the atoms per unit-cell and the total volume occupied by the unit-cell.

Ans: (b) ratio of the volume of the atoms per unit cell to the total volume occupied by the unit-cell

(a) 0.68
(b) 0.74
(c) 0.90
(d) 1.0.

Ans:  (b) 0.74

##### Q43. The force of attraction, force of repulsion and the resultant force between atoms versus atomic spacing r is shown in Fig. 11.4. The variation of force of attraction with r is given by

(a) curve A
(b) curve B
(c) curve C
(d) none of the above.

Ans:  (a) curve A

##### Q44. The equilibrium spacing between the atoms generally varies form

(a) 10–4 cm to 10–5 cm
(b) 10–5 cm to 10–6 cm
(c) 10–6 cm to 10–7 cm
(d) 10–8 cm to 4 × 10–8 cm.

Ans:  (d) 10–8 cm to 4 × 10–8 cm.

##### Q45. Choose the wrong statement

(a) The bonding energy is defined as the energy to separate the atoms completely.
(b) The repulsive forces between atoms are caused by the interaction of their electron shells.
(c) The equilibrium spacing between the atoms is of the older of 10–8 cm.
(d) High cohesive forces produce small elastic constants, small melting point and small co-fficients of thermal expansion.

Ans:  (d) High cohesive forces produce small elastic constants, small melting point and small co-fficients of thermal expansion.

##### Q46. The property of material to be strongly attracted to a magnetic field and to become a powerful magnet, is known as

(a) hysteresis
(b) polymerization
(c) ferromagnetism
(d) polymorphism.

Ans:  (c) ferromagnetism

##### Q47. Which of the following geometrical shapes are used for indenters?

(a) cones
(b) spheres
(c) pyramids
(d) all of the above.

Ans:  (d) all of the above.

##### Q48. The wrought iron is having

(a) tensile strength minimum and ductility maximum in the longitudinal direction
(b) tensile strength maximum and ductility minimum in the longitudinal direction
(c) tensile strength and ductility maximum in the longitudinal direction
(d) tensile strength and ductility minimum in the longitudinal direction.

Ans:  (c) tensile strength and ductility maximum in the longitudinal direction

##### Q49. Low carbon steel contains carbon from

(a) 0.05 to 0.1%
(b) 0.1 to 0.2%
(c) 0.3 to 0.85%
(d) 0.85 to 1.3%.

Ans:  (b) 0.1 to 0.2%

##### Q50. High carbon steel contains carbon from

(a) 0.05 to 0.1%
(b) 0.1 to 0.2%
(c) 0.3 to 0.85%
(d) 0.85 to 1.3%.

Ans:  (d) 0.85 to 1.3%.

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##### Read More Sections of Engineering Materials

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Engineering Material Objective Questions – Section-1

Engineering Material Objective Questions – Section-2

Engineering Material Objective Questions – Section-3

Engineering Material Objective Questions – Section-4