The energy stored in a material when it is deformed elastically is known as:

The correct answer, which identifies the energy stored in a material when it undergoes elastic deformation, is strain energy. When a material is deformed elastically, it means that it returns to its original shape once the applied load is removed. During this process, energy is absorbed and stored in the material's molecular structure as it stretches or compresses.

Strain energy is specifically associated with this reversible change. It is quantified by the material's modulus of elasticity and the extent of deformation. Understanding strain energy is crucial in fields such as mechanical engineering, structural engineering, and material science, as it helps in predicting how materials behave under different loading conditions.

Potential energy refers to the energy held by an object due to its position relative to other objects, while kinetic energy pertains to the energy of motion. Thermal energy relates to the temperature of an object and the energy contained within its internal structure. Although all these forms of energy are important in different contexts, they do not specifically relate to the energy stored during elastic deformation.