Wave parameters on a displacement-time graph

Steps:

• Examine the graph axes: vertical shows water height (displacement), horizontal shows time.
• Identify p as the maximum vertical extent from equilibrium, representing peak displacement.
• Identify q as the horizontal distance for one complete wave cycle, representing the period.
• Rule out spatial terms like wavelength, as the graph lacks distance data.

Why A is correct:

• In wave terminology, displacement is the height variation, and period is the time for one cycle; the graph directly measures these as p (max displacement) and q (time interval).

Why the others are wrong:

• B and D include wavelength, a spatial distance between wave crests, unmeasurable on a time-only graph.
• C uses "amplitude" for p, but the graph labels it as displacement (height), not the technical amplitude term.

Final answer: A