Physics / Foundations
Describe travelling disturbances with frequency, wavelength and amplitude.
A wave transfers energy through a travelling disturbance. In a transverse wave the oscillation is perpendicular to travel; in a longitudinal wave it is parallel.
Frequency counts cycles per second. Wavelength is the distance between points in the same phase, and period is the time for one cycle. Amplitude describes the maximum displacement, not the distance a wave travels.
Shake one end of a rope and a disturbance travels along it, while a marked point mainly moves up and down. The wave transports energy without requiring that point to travel to the far end. In sound, particles oscillate back and forth along the direction of propagation.
Amplitude is the greatest displacement from the resting position. Wavelength separates equivalent positions, such as neighbouring crests. Frequency counts cycles each second, while period times one cycle. A large amplitude does not by itself imply high frequency.
If ten crests pass a point each second and consecutive crests are 0.5 m apart, the pattern advances at 10 × 0.5 = 5 m/s. In one unchanged medium, increasing frequency usually shortens wavelength rather than simply increasing wave speed. Label which conditions remain fixed.
No. A taller wave has greater amplitude; speed depends on the medium and wave conditions, not amplitude alone in the simple model.
Wave speed equals frequency times wavelength.
Period and frequency are reciprocals.
A wave has frequency 5 Hz and wavelength 2 m. What is its speed?
v = 5 × 2 = 10 m/s.
Keep string tension fixed, increase frequency and observe how wavelength changes.
Follow one marked point and then follow a crest. Comparing those motions helps separate particle oscillation from wave travel.
Maximum displacement from equilibrium
Amplitude measures how far a point oscillates from its equilibrium position.
10 m/s
v = 5 × 2 = 10 m/s.
0.25 s
T = 1/4 = 0.25 s.