Que: The total area under the stress-strain curve of a mild steel specimen tested upto failure under tension is a measure of its (Gate-2002)

(a) Breaking Strength
(b) Toughness
(c) Hardness
(d) Stiffness

Ans: (b)
Explanation: Breaking strength is the maximum stress that a material can withstand while being stretched or pulled before failing or breaking so its not related with strain only stress are considered,
                    Hardness is the resistance of a material to localized deformation so hardness is propositional to accepted load before any deformation at here strain = change in length / original length are not consider.
                  Toughness is the ability of a material to absorb energy and plastically deform before fracturing and absorb energy per unit volume calculated by area under the stress-strain curve.