Question & Answer
QUESTION

Which of the following stress is known as the breaking stress of a material?
${\text{A}}{\text{.}}$ The stress in a material after fracture happens.
${\text{B}}{\text{.}}$ The maximum amount of tensile stress that the material can withstand before failure, such as breaking or permanent deformation.
${\text{C}}{\text{.}}$ The maximum amount of tensile stress that the material can withstand before elastic limit.
${\text{D}}{\text{.}}$ The maximum amount of tensile stress that the material can withstand in the elastic limit region.

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Hint: Here, we will proceed by keeping in mind the stress-strain curve of any material which will help to define each of the stresses given in the options in the problem. This tells us the definition of the breaking stress of a material.

Complete step-by-step answer:

According to the definition of the fracture stress, fracture strength or fracture stress is the stress in a material at which a specimen fails via fracture. This is the stress in a material after fracture happens. So, the stress given by option A represents fracture stress of a material not breaking stress of a material.

According to the definition of the breaking stress, the breaking stress of a material is the maximum amount of tensile stress that the material can withstand before failure, such as breaking or permanent deformation.

Breaking stress is a limiting state of tensile stress that leads to tensile failure when the stress in a body goes beyond the breaking stress of the material of which the body is made.
The maximum amount of tensile stress that the material can withstand before the elastic limit is known as yield stress and is given by Hooke’s law which states that the stress applied is directly proportional to the strain developed in the body due to that stress. So, the stress given by option C represents yield stress of a material not breaking stress of a material.

Also, the maximum amount of tensile stress that the material can withstand in the elastic limit region is also known as yield stress of the material. So, the stress given by option D represents yield stress of a material not breaking stress of a material.

Therefore, option B is correct.

Note: The stress applied to a material is the force per unit area applied to the material. Tensile means the material is under tension. The forces acting on it are trying to stretch the material. Compression is when the forces acting on an object are trying to squash it.