Question

Which of the following factors can bring about a change in the elastic properties of a material?
A. Length of the material
B. Change in temperature
C. Presence of impurities
D. None of the above

Answer 1

Let us understand the concept of elasticity first. Elasticity is the ability of a body to return to its original size and shape when the deforming force is removed. The elasticity of materials is described by a stress–strain curve.

Complete step by step answer:
A small piece of rubber and a large piece of rubber have the same elastic modulus. All materials have an elastic limit beyond which, if continuous stress is applied, they're going to start losing their ability to exhibit perfect elastic behaviour and begin deforming.

For example: while constructing a bridge, a load of traffic that it can withstand should be adequately measured beforehand. To prevent the problem of bending under force the elastic behaviour of the material used must be considered. Plasticity or plastic deformation is the opposite of elastic deformation and is defined as unrecoverable strain.

Temperature: Because the temperature increases, intermolecular forces decrease, leading to a decrease within the elasticity.

Impurities: Counting on the character of the impurities, the elasticity of an object can either increase or decrease. For example: When potassium is added to gold, the elastic property of gold increases. When carbon is added to molten iron, the elastic property of iron decreases provided the carbon content should be quite 1% in iron.

Therefore option B and C are correct.

Note: When one talks about elasticity then it does not mean that if a particle is stretched highly then it is elastic but elasticity means how easily a particle gains it's position after removal of external force. That's why steel is more elastic than rubber though rubber is more stretchable than steel.