A Level Physics Practice Exam

What represents the oscillation of a medium in longitudinal waves?

1. Wavelength

2. Node

3. Crest

4. Compression and rarefaction

The correct answer is: Compression and rarefaction

In longitudinal waves, the oscillation of the medium occurs through alternating regions of compression and rarefaction. Compression refers to the areas where the particles of the medium are pushed closer together, resulting in increased pressure and density. Conversely, rarefaction is the region where the particles are spread apart, leading to a decrease in pressure and density. This back-and-forth movement through these areas generates the characteristic waveform of longitudinal waves, such as sound waves. The amplitude and frequency of these compressions and rarefactions define the wave’s energy and pitch, respectively. Understanding this concept is crucial in differentiating how longitudinal waves operate compared to transverse waves, which involve oscillations that move perpendicular to the direction of the wave's travel.