Question

The ability of the material to deform under stress and return to its original shape when the stress is removed is called

• A. Elasticity
• B. Plasticity
• C. Brittleness
• D. Stiffness

Hint:

(l) \textbf{Elasticity:} Ability of a material to deform under load and return to its original shape upon removal of the load. Deformation is recoverable.
(m) \textbf{Plasticity:} Ability of a material to undergo permanent deformation beyond its elastic limit.
(n) \textbf{Brittleness:} Tendency to fracture with little plastic deformation.
(o) \textbf{Stiffness:} Resistance to elastic deformation (measured by Young's modulus).

Answer 1

The Correct Option is A

The question describes a fundamental mechanical property of materials.
(h) (a) Elasticity: This is the ability of a material to undergo deformation when subjected to stress (load) and then to return to its original shape and size once the stress is removed. This deformation is temporary and recoverable. Hooke's Law (stress is proportional to strain) often applies within the elastic limit.
(i) (b) Plasticity (Plastic Deformation): This is the ability of a material to undergo permanent deformation (change in shape or size that is not recovered) when subjected to stress beyond its elastic limit. The material does not return to its original shape after the stress is removed.
(j) (c) Brittleness: Brittleness is the property of a material that causes it to fracture (break) with little or no prior plastic deformation when subjected to stress. Brittle materials (e.g., glass, cast iron) absorb little energy before fracturing. The opposite of ductility.
(k) (d) Stiffness (Rigidity): Stiffness is a measure of a material's resistance to elastic deformation under stress. A stiff material requires a large stress to produce a small strain (it has a high Young's modulus). It describes the resistance to deformation, not the ability to recover from it. The description "The ability of the material to deform under stress and return to its original shape when the stress is removed" precisely defines Elasticity. \[ \boxed{\text{Elasticity}} \]