Which term would you use to describe the ability to deform unusually by stretching along its length?

• A. Elasticity
• B. Plasticity
• C. Ductility
• D. Toughness

Answer: (C)

Ductility describes a material’s ability to undergo significant plastic deformation by elongating under tensile force, often being drawn into a wire. This makes it the best fit for describing stretching along its length, since ductile materials can be stretched into long, narrow shapes without breaking. Elasticity would only show reversible changes that snap back when the load is removed, not permanent elongation. Plasticity is a broader idea of permanent deformation in general, but ductility specifically highlights elongation into a wire. Toughness is about how much energy a material can absorb before fracturing, not about how far it can be stretched. For example, copper is highly ductile and suitable for wires, while brittle materials show low ductility and tend to crack rather than elongate.