(a) Glass is more elastic than rubber because for a given applied force per unit area, the strain produced in glass is much smaller than the strain produced in rubber.

There is no perfectly elastic body but quartz fibre and Phosphor bronze are examples of near perfect elastic bodies. If a body does not regain its original configuration at all after the deforming force is removed, it is called perfectly plastic body. Examples of near perfect plastic bodies are wax, putty etc.

rubber

Answer. By this definition, steel is more elastic than rubber (gold) because steel comes back to its original shape faster than rubber (gold) when the deforming forces are removed.

Steel is more elastic as Young modulus of elasticity less than Alumnium. So Aluminium exhibits more stiffness comparing to steel and it is brittle too. One can easily observe this property from aluminum foils used in house hold use seldom reusable as it can not return back to its orginal plain shape.

Elastic limit, maximum stress or force per unit area within a solid material that can arise before the onset of permanent deformation. When stresses up to the elastic limit are removed, the material resumes its original size and shape. Stresses beyond the elastic limit cause a material to yield or flow.

Elasticity of steel is more than that of copper and so for equal applied force, the elongation of steel spring is less than that of copper for same initial length. Glass is more elastic than rubber because for a given applied force per unit area, the strain produced in glass is much smaller than produced in rubber.

Steel is more elastic than copper, brass and aluminium . Because of this reason steel is preferred in heavy duty, machines and in structural designs.

Answer: A good spring will be that in which a large restoring force is developed on being deformed. This in turn depends on the elasticity of the material of the spring. Since Young’s modulus for steel is more than that of copper, therefore the springs made of steel and not of copper.

Sound travels more quickly in mediums that have a high degree of elasticity because when the particles are compressed, the quickly spread out again. Solid materials are usually more elastic than liquids or gases, so compressions and rarefactions travel very well in solids.

*Elastic Limit* :the maximum extent to which a solid may be stretched without permanent alteration of size or shape. *Elastic Fatigue* :It is the property of an elastic body by virtue of which its behaviour becomes elastic under the action of repeated alternating deforming force.