Understanding Material Stiffness and Elastic Deformation

The question asks about the property of a material that describes its resistance to elastic deformation. Let's break down what elastic deformation means and then look at the options provided.

Elastic Deformation: When a material is subjected to a load or force, it changes shape or size. If this deformation is temporary and the material returns to its original shape and size after the load is removed, it is called elastic deformation. This is like stretching a rubber band – it deforms but springs back.

Now let's consider the options:

• Stiffness: Stiffness is a measure of a material's resistance to elastic deformation. A stiff material requires a large force to produce a small elastic deformation. Think of steel versus rubber; steel is much stiffer.
• Resilience: Resilience is the ability of a material to absorb energy elastically and then release it when unloaded. It is the energy absorbed per unit volume within the elastic limit.
• Hardness: Hardness is the resistance of a material to plastic deformation, typically by indentation or scratching. This is different from elastic deformation, which is temporary.
• Ductility: Ductility is the ability of a material to deform plastically under tensile stress before fracturing. Ductile materials can be drawn into wires.

Comparing these definitions, the property specifically describing the resistance to elastic deformation is stiffness.

In simpler terms, when you push or pull on a material, how much it stretches or bends elastically for a given force tells you about its stiffness. A material that doesn't stretch or bend much under load (within its elastic limit) is considered stiff.

Therefore, the correct term for the resistance of a material to elastic deformation is stiffness.