Question

Draw a curve showing density or pressure variations with respect to distance for a disturbance produced by sound. Mark the position of compression and rarefaction on this curve. Also, define wavelength and time period using this curve.

Answer 1

1. In the below diagrams, C represents the compression region(regions of high pressure) and R represents the rarefaction region(regions of low pressure)
2. A maximum compression region corresponds to a crest(maximum upward displacement point in a wave) since the pressure and density are maximum. Similarly, the maximum expanded region is equivalent to a trough.
3. Wavelength: As seen in the third diagram, the distance between two consecutive crests or troughs is termed wavelength. In density and pressure diagrams the distance between consecutive compressed regions or expanded regions is termed wavelength.
4. Time period: Time period is defined as the time taken by the wave to complete one cycle i.e, time taken from one crest to the next crest or one trough to the next trough.