Hysteresis in rubber band force-extension graph

Steps:

• Examine the graph: loading curve shows extension with increasing force; unloading curve returns to zero extension at zero force.
• Identify if unloading reaches original length: it does, indicating elastic behavior.
• Check for straight-line proportionality: curve is nonlinear, so not Hooke's law.
• Note shaded area: likely the loop between loading and unloading, representing energy loss, not just extension work.

Why C is correct:

• Elastic deformation means the material returns to its original shape after force removal; the graph shows unloading to zero extension, confirming elasticity per the definition of elastic limit.

Why the others are wrong:

• A: Hooke's law requires a straight line through origin (F = kx); the nonlinear curve violates this.
• B: Unloading curve reaches zero extension at zero force, so it returns to original length.
• D: Shaded area is the hysteresis loop (energy dissipated as heat); work in extending is only under loading curve.

Final answer: C