What are .beats. ? Explain their production. State the necessary conditions for the production of beats.

Explanation

When two sound waves of .nearly. equal frequencies are produced simultaneously, then the intensity of the resultant sound produced by their super position increases and decreases alternately with time. This phenomenon of rise and fall in the intensity of sound is called the beat. Explanation :
The phenomenon of beats is a particular example of the interference of sound. When two sound sources are sounded together two waves travel in the medium. If these two waves meet at a point in the same phase then the intensity of sound at that point is maximum but if they meet in opposite phases then the intensity of sound is minimum. The essential conditions for production of beats are:
(i) The amplitudes of two waves should be nearly equal.
(ii) The difference in frequencies of two sources must be less than 10.