Engineering Questions with Answers - Multiple Choice Questions

Materials Science MCQ’s – Linear Defects – 1

1 - Question

A dissolution in which an extra portion of a plane of atoms or a half plane terminates within a crystal is called as ________
a) Edge dislocation
b) Mixed dislocation
c) Interfacial dislocation
d) Screw dislocation
View Answer Answer: a
Explanation: Edge dislocations are the linear crystalline defects that are formed due to the extra half plane of atoms in the lattice.

2 - Question

The magnitude and direction of lattice distortion are expressed in terms of which vector?
a) Dislocation vector
b) Screw vector
c) Edge vector
d) Burger vector
View Answer Answer: d
Explanation: Burger vector is used to denote magnitude and direction. In physics, the Burgers vector, named after Dutch physicist Jan Burgers, is a vector, often denoted as b, that represents the magnitude and direction of the lattice distortion resulting from a dislocation in a crystal lattice.

3 - Question

What is the relative orientation of dislocation lines for edge dislocation?
a) Parallel
b) Perpendicular
c) Circular
d) Both parallel and perpendicular
View Answer Answer: b
Explanation: For edge dislocation the nature of dislocation line is perpendicular.

4 - Question

What type of direction will the burger vector of dislocation for a metallic material show?
a) Closed-packed crystallographic direction
b) Rounded-packed crystallographic direction
c) Open-packed crystallographic direction
d) Parallel-packed crystallographic direction
View Answer Answer: a
Explanation: For a metal being solid, its atoms are closely packed and also metals are crystalline in nature so the direction shown by the vector will be closed packed crystalline direction.

5 - Question

Which technique is used to observe dislocation?
a) Positron annihilation technique
b) Thermal imaging
c) Thermal expansion measurements
d) Electron-microscope technique
View Answer Answer: d
Explanation: This type of microscope consists of a high magnification transmission electron micrograph in which dark lines represent dislocation.

6 - Question

Path of screw dislocation is in the form of _______
a) Circular
b) Cylindrical
c) Spiral or helical
d) Rectangular
View Answer Answer: c
Explanation: Ramp that is traced around dislocation line is spiral or helical that’s the reason it is called screw dislocation.

7 - Question

Which type of deformation occurs due to dislocation?
a) Slip plastic deformation
b) Elastic deformation
c) It does not show deformation
d) Slip elastic deformation
View Answer Answer: a
Explanation: Dislocation involves sliding of crystal blocks over one another along the definite crystallographic plane which results in a slip.

8 - Question

Which type of stress is involved in the motion of screw dislocation?
a) Tensile stress
b) Shear stress
c) Compressive stress
d) Does not involve stress
View Answer Answer: b
Explanation: If shear stress is increased in screw dislocation it results in a slip of one layer over other which ultimately leads to deformation.

9 - Question

Which type(s) of dislocation are included in mixed dislocation?
a) Only Edge dislocation
b) Only shear dislocation
c) Only screw dislocation
d) Both edge and screw dislocation
View Answer Answer: d
Explanation: Mixed dislocation is a combination of screw and edge dislocation. It does not consist of only pure edge or pure screw dislocation.

10 - Question

What is the mechanism in which edge dislocation move out of the slip is called _______
a) Climb dislocation
b) Screw dislocation
c) Shear dislocation
d) Slip dislocation
View Answer Answer: a
Explanation: In this type of dislocation edge moves perpendicular over its slip plane.

Get weekly updates about new MCQs and other posts by joining 18000+ community of active learners