Question

Which wave property determines loudness and pitch, and what is the nature of sound waves?

Answer 1

Sound is a wave and waves described by various properties. That can be frequency of wave, amplitude of wave, wavelength of wave. From these properties loudness and pitch is dependent.

Complete step by step solution:
Loudness of a sound depends on its amplitude.
If the amplitude of a sound is huge, then the sound produced will also be loud.
The wave is described by a number of properties. One such property is amplitude. The amplitude of a wave is the highest displacement of a particle from its rest position. In other words, the amplitude is the distance from the rest position to the crest or, the distance between the rest position and the trough position.

The wavelength is another property of a wave. The wavelength of a wave is basically the length of one complete wave cycle. The wavelength is measured as the distance from crest to crest or from trough to trough. In simple words, the wavelength of a wave is measured as the distance from a point on a wave to the adjacent point on the next cycle of the wave. Pitch of a sound depends on its frequency.

A sound is considered as a high pitch sound when frequency of sound is high. The number of waves that passes a fixed point in a given amount of time is the wave frequency. Frequency can be measured by counting the number of crests which are high points of waves that pass the fixed point in one second. The higher the number is, the greater the frequency of the waves. The SI unit for wave frequency is the hertz (Hz), where one hertz equals to 1 wave passing a fixed point in one second. Sound waves are the mechanical, longitudinal wave.

As a mechanical wave, sound requires a medium. So, sound cannot propagate through a vacuum. Therefore there is no sound in outer space.

And as a longitudinal wave, sound is a rapid variation in pressure that propagates. Regions of above normal pressure are called compressions or condensations and regions of below normal pressure are called rarefactions or dilations.

Note: We have to remember that sound is a longitudinal wave and waves have different properties. So please remember what property is responsible for what quantities.