Question

The stress at which extension of the material takes place more quickly as compared to the increase in load is called
A) Elastic point of the material
B) Plastic point of the material
C) Breaking point of the material
D) Yield point of the material

Answer 1

Hint:Here we need to find a point, such that once that point is passed, some fraction of the deformation will be permanent and non-reversible and is known as plastic deformation.

Complete step by step answer:
The point beyond stress, in which a material is deformed to a relatively large amount for a small increase in stretching force is known as yield point. A small increase in stress beyond the yielding point will give rise to a large elongation

Thus option D is correct

Additional information:Yield strength is defined as the stress at which the material exhibits a certain limiting deviation from the stress ratio. This is the amount of stress required due to a predetermined static stress, typically 0.1 or 0.2%, called "percent offset". Yield strength is a property often used to describe the stress at which a material begins to function in a plastic way. The yield strength is represented by the point of intersection of the line parallel to the stress – strain curve.
Proportional limit, elastic limit and yield strength are defined separately, but in many ways their values ​​are quite close to each other. Effectiveness cannot be measured for brittle materials such as composites and ceramics.

Notes.The yield point is the property of the material, defined as the stress during which the material begins to deteriorate drastically. Before the yield point, the material is deformed and will return to its original position when the applied stress is removed.
Once the yield point passes, some fraction of the deformation will be permanent and irreversible.