What are the wavelength, frequency, time period and amplitude of a sound wave?

Wavelength(λ): Wavelength is defined as the distance between two consecutive compressions or rarefactions of a sound wave. 

Frequency(v): Frequency is the number of complete oscillations per unit time.

Time period(T): The time taken by two consecutive compressions or rarefactions to cross a fixed point is called the time period of the sound wave.

Amplitude(A): The magnitude of the maximum disturbance in the medium on either side of the mean value is called the amplitude of the wave.

Sound moves through a medium from the point of generation to the listener. When an object vibrates, it sets the particles of the medium around it vibrating. The particles do not travel all the way from the vibrating object to the ear. A particle of the medium in contact with the vibrating object is first displaced from its equilibrium position. It then exerts a force on the adjacent particle. As a result of which the adjacent particle gets displaced from its position of rest. After displacing the adjacent particle the first particle comes back to its original position. This process continues in the medium till the sound reaches your ear. 

The moon has no atmosphere or material medium through which sound can travel. Hence, the sound produced by our body cannot be propagated while we are on the surface of the moon. 

When the hammer is beaten on a school bell, it begins to vibrate and produces sound. We are able to feel the vibrations, if we gently touch the bell. Therefore, we can say that sound is produced by a vibrating body.

Mechanical waves is characterised by the motion of the particles of the medium. Sound needs a material medium like air, water, steel, etc. for its propagation. Hence, sound waves are called mechanical waves.