Engineering Questions with Answers - Multiple Choice Questions
Materials Science MCQ’s – Brittle Fracture
1 - Question
Which of the following is associated with minimum plastic deformation?
a) Ductile fracture
b) Brittle fracture
c) Fatigue
d) It doesn’t occur during fracture
View Answer
Explanation: In brittle fracture, the plastic deformation occurring in the body is minimum and there is a rapid movement of crack with a very little amount of plastic deformation.
2 - Question
Which of the following fracture mechanisms in which the crack propagates more rapidly?
a) Ductile fracture
b) Brittle fracture
c) Fatigue
d) It doesn’t occur during fracture
View Answer
Explanation: In brittle fracture, after a little plastic deformation the material fractures and then the crack propagates rapidly, making the material break.
3 - Question
Below which point does brittle fracture occur?
a) Ultimate tensile strength
b) Fracture point
c) Elastic limit
d) Yield point
View Answer
Explanation: Fatigue is one of the mechanical failures of the metals that occur due to cyclic loading. It occurs when the stress applied is less than the yield stress or yield point.
4 - Question
Cleavage planes are a term associated with ductile fracture.
a) True
b) False
View Answer
Explanation: Brittle fracture occurs generally along crystal planes called cleavage planes where the number of atomic bonds are relatively low.
5 - Question
The tendency of brittle fracture increases with:
a) Decreasing temperature
b) Increasing temperature
c) Decrease in strain rate
d) It doesn’t depend on temperature or strain rate
View Answer
Explanation: The tendency of brittle fracture to be observed increases as the temperature decreases.
6 - Question
The tendency of brittle fracture increases with:
a) Increasing temperature
b) Increase in strain rate
c) Decrease in strain rate
d) It doesn’t depend on temperature or strain rate
View Answer
Explanation: The tendency of brittle fracture to be observed increases as the strain rate of the body increases. As the strain rate increases the body dislocations start piling up and ultimately leading to failure.
7 - Question
Which of the following statement is true regarding the toughness of a metal?
a) Energy consumed is less in ductile fracture than brittle fracture
b) Energy consumed is more in ductile fracture than brittle fracture
c) Energy consumed in the brittle fracture is same as the ductile fracture
d) Energy consumed is more in brittle fracture than ductile fracture
View Answer
Explanation: As brittle fracture less plastic deformation and absorbs less amount of energy before breaking, the energy consumed by brittle fracture is less than the ductile fracture.
8 - Question
Which of the theory is related to brittle fracture?
a) Laundau theory
b) Dirac hole theory
c) Valence bond theory
d) Griffith’s theory
View Answer
Explanation: Griffith’s theory is a theory which was postulated by Griffith and is related to brittle fracture. It is known as Griffith’s theory of brittle fracture.
9 - Question
The graph for Griffith’s crack is ____________
a) An ellipse
b) A circle
c) A straight line
d) A hyperbola
View Answer
Explanation: The graph for Griffith’s crack is an ellipse. The graph tensile stress applied perpendicular to the length of crack and the length of the crack.
10 - Question
Surface energy of the specimen increases when the crack lengthens.
a) True
b) False
View Answer
Explanation: When the crack lengthens the surface area increases and hence the surface energy of the specimen increases.