**Question 12**

**State and explain Hooke’s law. Define longitudinal stress, longitudinal strain and Young’s modulus.**

Hooke’s law states that the force required to extend or compress a spring by a distance is directly proportional to that distance. In other words, the more you stretch or compress a spring, the more force it will require. This relationship is known as the spring constant, and it is a measure of the stiffness of the spring. Hooke’s law is used to describe the behaviour of springs and other elastic materials.

**Longitudinal stress:**The stress that occurs when a force is applied in the longitudinal direction of a material, causing it to elongate or compress.**Longitudinal strain:**The resulting deformation of a material caused by the application of longitudinal stress.**Young’s modulus:**A measure of the stiffness of a material, defined as the ratio of longitudinal stress to longitudinal strain.