Wave motion Summary:
1. Simple harmonic motion (SHM) is a kind of vibratory motion in which acceleration of the body is directly proportional to the displacement from equilibrium position and always directed towards the equilibrium position.
2. The motion of mass attached to spring and that of simple pendulum is SHM.
3. The kind of waves which require a medium for their propagation are called mechanical waves.
4. Transverse waves are the kind of mechanical waves in which particles of the medium vibrate about their mean position perpendicular to the direction of propagation of the waves.
5. Compressional waves are those mechanical waves in which particles of the medium vibrate about the equilibrium position in the direction of propagation of the waves.
6. Wave is a source of transferring energy from one place to another.
7. The wave speed (v) of a wave is equal to the product of frequency (f) and wavelength…………………………….. 
8. When waves enter from one medium to another, a part of it is reflected in the same medium while the other medium. This phenomenon is called refraction of waves. The wave speed and wavelength of a wave change in the second medium but frequency does not change.
9.The bending of waves around obstacles is called diffraction.
10. When particles of medium are subjected to two or more than two waves simultaneously, the effect being produced is called interference.
11. When two identical waves pass through a medium along the same line in opposite directions, then stationary waves are produced at certain frequencies.