Which is more elastic iron or rubber why?

This is a common misconception - iron is actually more elastic than rubber! Here's why:Elasticity refers to a material's ability to return to its original shape and size after deformation forces are removed, not just its ability to stretch.Iron:- Can withstand much greater stress before permanent deformation- Returns completely to original dimensions when stress is removed within elastic limit- Has higher Young's modulus (measure of stiffness)Rubber:- Can stretch much more (higher strain) but doesn't fully return to original dimensions- Exhibits hysteresis - some energy is lost as heat during deformation-recovery cycle- Undergoes permanent deformation more easilySo while rubber is more flexible and can undergo larger deformations, iron is more elastic because it better maintains its original structure after stress removal. This is why steel is used in springs and structural applications where reliable recovery from stress is crucial.

From my materials science background, the key distinction is:Iron has a steep stress-strain curve - it requires significant force to cause small deformations, but it returns completely to its original shape when that force is removed (within its elastic limit).Rubber has a shallow stress-strain curve - it deforms easily under small forces, but doesn't fully recover its original dimensions due to its polymer chain structure slipping and not completely returning.The modulus of elasticity (Young's modulus) for steel is about 200 GPa, while for rubber it's only 0.01-0.1 GPa. This higher modulus indicates greater stiffness and better elastic behavior in iron.In practical terms: if you stretch a rubber band multiple times, it becomes permanently longer. If you bend an iron rod within its elastic limit, it springs back perfectly every time. That perfect recovery makes iron the more elastic material.