Q1: Work hardening of a material

ANS:B - decreases its ductility.

Work hardening of a material decreases its ductility. Work hardening, also known as strain hardening or cold working, is a process in which a material becomes harder and stronger as a result of plastic deformation. When a material undergoes plastic deformation, dislocations in its crystal lattice structure move and multiply, creating internal stresses within the material. These internal stresses hinder the movement of dislocations, making it more difficult for them to continue deforming the material. As a result, the material becomes harder and stronger. However, while work hardening increases the strength and hardness of a material, it typically reduces its ductility. Ductility refers to the ability of a material to deform plastically before fracturing. As work hardening progresses, the material's ability to deform plastically decreases because the increasing number of dislocations and internal stresses limit further plastic deformation. This reduction in ductility can lead to brittleness and an increased tendency for the material to fracture under stress. Therefore, work hardening of a material generally decreases its ductility while increasing its strength and hardness.