What is the stress vs strain equation used to determine the relationship between the applied force and resulting deformation in a material?

The stress vs strain equation, also known as Hooke's Law, is used to determine the relationship between the applied force and resulting deformation in a material. It is expressed as stress E strain, where stress is the force applied to the material, strain is the resulting deformation, and E is the material's Young's Modulus, which represents its stiffness.