Characteristics of wave motion
(i) A wave is produced due to periodic disturbance at a point in a medium. Due to wave propagation in a medium, the particles of medium vibrate periodically about their mean positions.
(ii) When a wave travels in a medium, energy is transferred without the physical transfer of matter or without the flow of the medium as a whole. For a mechanical wave, energy is transferred through the vibrations of the medium particles about their mean positions.
(iii) The energy transfer in the medium takes place with a constant speed which depends on the nature of the medium.
(iv) If there is more than one wave travelling through a medium, each wave moves as though others are not present and, therefore, the total displacement at any point at a given time is obtained by the algebraic sum of the corresponding displacements of the individual waves. This is called the principle of superposition. This principle helps us to explain the phenomenon such as interference of waves, reflection of waves, formation of standing waves, beats, etc.
Distinction between the light and sound waves:
|Light waves||Sound Waves|
|1. These are electromagnetic radiations||1. These are mechanical waves|
|2. They can travel in vacuum||2. They require a material medium tom propagate|
|3. The speed of light waves is very high ( 3×108 m/s in air)||3. The speed of sound waves is low (330 m/sin air)|
|4. The wave length of visible light is very small of the order 10-6 m||4. The wave length of sound waves is in the range of 10-2 m to 10 m|
|5. These waves are transverse||5. These waves are longitudinal|