Define plastic deformation and tensile strength.

(N/A) $1$. Plastic Deformation: It is the permanent deformation of a material that occurs when the applied stress exceeds the elastic limit of the material. In this state,the material does not return to its original shape or size even after the removal of the external deforming force.
$2$. Tensile Strength: It is defined as the maximum stress that a material can withstand while being stretched or pulled before breaking or failing. It is calculated as the ratio of the maximum load applied to the original cross-sectional area of the material.