Elasticity is defined as the property of materials by which a body regains its original (position) shape and size when the external deforming forces are withdrawn. All solid, liquid and gaseous materials possess this property. The material possesses this property due to its intermolecular force.
Due to the change of molecular distances inter molecular force will change. As the distance decreases, the force of attraction will increase. But when the force of attraction will be maximum, then if the distance decreases more, the force of repulsive will act and time will come when force of attraction will be equal to force of repulsion – at this time molecular force will be zero.
During the formation of matter the spherical molecules stay close to each other with small vacant space between the molecules. This vacant space is called inter molecular space. This space is in the order of 10-9m to 10-10m. Being separated by this distance. There exists a force of attraction between the molecules. This force is called intermolecular force. This force is electrical in nature.