The formula Ep = 12kx^2 applies only when:

  1. the deformation is plastic
  2. the material has broken
  3. the material obeys Hooke's law (within the limit of proportionality)
  4. the force is zero
Answer

C) the material obeys Hooke's law (within the limit of proportionality)

It comes from a straight-line graph. SLO P-11-B-28 · Application

Physics MCQ · More Deformation of Solids MCQs · Practise