Which statement best describes the Modulus of Elasticity?

• A. The ratio of stress to strain
• B. The energy stored per unit volume
• C. The measure of resistance to elastic deformation
• D. The mass density of the material

Answer: (C)

Modulus of Elasticity represents how stiff a material is—how strongly it resists elastic, or reversible, deformation under load. In the linear elastic range, stress and strain follow Hooke’s law, sigma = E * epsilon, so a larger modulus means the material deforms less for the same applied stress. Describing it as the measure of resistance to elastic deformation communicates this physical property directly: it’s about stiffness, not about energy stored or mass. The energy-per-volume idea is a different concept (the energy stored depends on both stress and strain), and mass density has no direct relation to how a material deforms elastically. So describing it as the resistance to elastic deformation best captures what the modulus tells you about the material.