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
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
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?
d) Both parallel and perpendicular
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
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
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 _______
c) Spiral or helical
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
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
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
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
Explanation: In this type of dislocation edge moves perpendicular over its slip plane.