State Hooke's Law, with graphical representation.

Hint:Hooke's Law, or law of elasticity is the fundamental principle behind spring scale, the manometer, balance wheel of the mechanical clock and many other crucial things in mechanics.

Complete step by step answer:
1. Hooke’s Law was given by the scientist Robert Hooke.
2. It states that within the elastic limit, stress developed is directly proportional to the strain produced in the body. Hence, Stress = k × strain, where k is the proportionality constant, and is called modulus of elasticity.
3. For instance, consider a body on which we apply an external force. As a result, stress is developed in the body, which in turn develops a strain (deformation) in the body.
4. Hence, because of stress, strain is consequently produced in the body. According to Hooke's Law, if strain increases, then the stress will increase and vice versa.
5. This law is applicable to all elastic materials. It is not applicable to plastic deformation.
This is the graphical representation of Hooke’s Law-
 6. As stated above, Hooke’s law is followed up to the point C. That is, strain and stress are directly proportional to each other.
7. After that point, plasticity comes into play, hence Hooke’s Law I not followed there. The point F is the ultimate fracture point, where the material breaks.



Note:Most of the students get confused between Hooke’s law and restoring force so always remember that Hooke’s law is one of the types of restoring force and always remember it’s formula. It helps in solving various numerical problems.