Question

Why are sound waves in air characterized as longitudinal?

Answer 1

Hint- Here, we will proceed by defining mechanical waves under which a sound wave falls. Then, we will be discussing the types of mechanical ways i.e., Transverse waves and Longitudinal waves.

Complete step-by-step solution -
Sound travels as waves of energy, but, unlike light, the waves transmit energy by changing the motion of particles.
A mechanical wave is a wave that is not capable of transmitting its energy through a vacuum. Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave. Sound waves are incapable of traveling through a vacuum.
Mechanical waves are of two types -
(1) Transverse waves –The waves having vibrations of the medium perpendicular to the direction of the propagation of waves are known as transverse waves.
(2) Longitudinal waves - The waves having vibrations of the medium parallel to the direction of the propagation of waves are known as longitudinal waves.
Longitudinal waves are waves in which the motion of the individual particles of the medium is in a direction that is parallel to the direction of energy transport. A longitudinal wave can be created in a slinky if the slinky is stretched out in a horizontal direction and the first coils of the slinky are vibrated horizontally. In such a case, each individual coil of the medium is set into vibrational motion in directions parallel to the direction that the energy is transported.
The vibrations of the object set particles in the surrounding medium in vibrational motion, thus transporting energy through the medium. For a sound wave traveling through air, the vibrations of the particles are best described as longitudinal.
Sound waves in air (and any fluid medium) are longitudinal waves because particles of the medium through which the sound is transported vibrate parallel to the direction in which the sound wave moves.

Note- Sound wave can be described by five characteristics which includes wavelength, amplitude, time period, frequency and velocity or speed The minimum distance in which a sound wave repeats itself is called its wavelength. It is the length of one complete wave. The number of complete waves or cycles produced in one second is called frequency of the wave.