Wavelength from wave speed and frequency determined from displacement-time graph

Steps:

• Identify the period T from the graph as the time for one complete displacement cycle, approximately 0.018 s.
• Calculate frequency f = 1/T ≈ 56 Hz.
• Use the formula λ = v / f, where v = 340 m/s, to get λ ≈ 6 m.
• Compare to options to select the closest match.

Why A is correct:

• λ = v / f directly yields 6 m using the graph's period and sound speed formula.

Why the others are wrong:

• B underestimates λ by assuming a shorter period (higher f) than shown.
• C overestimates λ by assuming a longer period (lower f) than the graph indicates.
• D greatly overestimates λ by doubling the assumed period.

Final answer: A