1. The sound wave can also be called as elastic wave and medium is needed for their propagation. Their velocity is different for different media.

2. The velocity of sound waves depends on the property of inertia and coefficient of elasticity of that medium.

3. In this type of motion the energy is transferred from one point to other by the propagation of disturbance in the medium. The motion of disturbance is called the wave motion.

4. In simple harmonic wave the particles of the medium execute simple harmonic motion. Each particles of the medium executes simple motion at all the times, though the phase of its vibratioe classified in two type;

a) Transverse wave

b) Longitudinal waven depends on its position and time. On the basis of the particles, waves ar

Transverse wave :The particles of the medium vibrate in a direction perpendicular to the direction of wave. Their polarization is possible, example: vibration of the string, the surface of solid and liquid.





Longitudinal wave : Vibration of the particles of the medium are in the direction of wave propagation. Wave proceeds in form of compression and rarefaction. At places of compression the pressure and density are maximum, while at places of rarefaction those are minimum.

Example: Sound wave, waves is gases, wave is solid.





2. Some important points related with the wave motion.

(i) Amplitude: The maximum displacement of a vibrating particle of the medium from the mar position.

(ii)Time period (T) : The time taken by the particle to complete one vibration.

(iii)Frequency: The number of infraction in one second by the particle n=1/t



(iv) Wavelength (2) : The distance between two consecution particles infracting in the same phase

Or

The distance between two consecutine creets or trough
Or
The distance between two consecutine compressions or rarefaction

here v is the nelocity of wave. is the wave propagation vector which is written as:
being the unit vector along direction of wave propagation, then



3. Equation of the progressine simple harmonic wane.

(1) The equation of a wane moving along the direction of positine
where 'a' is the amplitude, is the phase difference and 'y' is the displacement of a particle.

(ii)The equation of a progressine wane moving along the direction of negative x - axis is

(iii) The general equation of wane moving along x- axis is: