Waves on a string and pipes play an important role in music. String instruments produce sound by vibration of the string and wind instruments produce sound by vibration of sound waves in the pipe. In this section we will discuss, how the different modes of vibrations are produced in these instruments. Almost all the musical instruments that produce music can be grouped in three major classes.

1. String instruments: - produce musical sounds by vibrating strings. Examples: piano, guitar, violin, flute, cello.

2. Wind instruments: - Produce musical sounds when wind is blown into or through a tube.
Examples: clarinet, flute, trumpets and saxophones.

3. Percussion instruments:- Produce musical sounds when struck by something.

Key terms

• The property of light travelling in a straight line is called as the rectilinear propagation of light.