Displacement-time graph shows shortening oscillation periods

Steps:

• Examine the graph: particle displacement oscillates sinusoidally over time.
• Identify peaks: successive peaks occur closer together as time progresses.
• Measure intervals: time between peaks (period T) decreases.
• Calculate frequency: f = 1/T, so decreasing T means increasing f.

Why B is correct:

• Frequency f is oscillations per second; graph's compressing cycles directly show f rising per the wave equation y = A sin(2πft + φ).

Why the others are wrong:

• A: Amplitude is peak displacement height; graph shows no increasing height.
• C: Period T is time per cycle; shortening intervals mean T decreases.
• D: Speed v = fλ requires spatial data; time graph alone shows no velocity change.

Final answer: B