Types of waves:
A wave is a disturbance in a medium which carries energy without a net movement of particles. A sound wave is a mechanical wave why because a mechanical wave cannot be transmitted in a vacuum.
Types of waves
There are two types of mechanical waves.
  • Longitudinal wave
  • Transverse wave
Longitudinal wave:
The wave that vibrates in the direction of the motion is called a longitudinal wave. Sound waves are longitudinal because the particles of the medium vibrate in the direction which is parallel to the direction of the propagation of the sound waves. The particles in the medium oscillate to and fro in the case of longitudinal waves.
Transverse waves:
A transverse wave is a wave which is produced when the particles of the medium oscillate in a direction that is perpendicular to the direction of the propagation of the wave. The particles in a transverse wave oscillate in an up and down motion. For example, light waves are transverse in nature.
Important terms to describe sound waves
A Sound wave can be described by its
  • Wavelength
  • Frequency
  • Time period
  • Amplitude
  • Speed
The distance between the two consecutive compressions or the two consecutive rarefactions is called the wavelength.
It is denoted by a Greek letter lambda(λ), and its unit is \(metre(m)\) .
The number of oscillations an object takes per second is called its frequency. It is denoted by the letter F.
The SI unit of frequency is \(Hertz(Hz)\) .
Time period:
The time taken for one complete oscillation of a sound wave is called the time period of the sound wave.
It is denoted by the letter T, and its unit is \(second(s)\) .
The maximum displacement of a particle of the medium from the mean position is called the amplitude of the wave.
Amplitude defines the loudness of sound.
It is denoted by the letter A, and its unit is \(metre(m)\) .
The distance travelled by a wave in one second is called the speed or velocity of the wave.
It is denoted by the letter v, and its unit is \(metre per second \)\((m/s)\) .