Question

A sitar wire and a tabla when sounded together give four beats/s. What do we conclude from this? As the tabla membrane is tightened, the beat rate may decrease or increase. Explain.

Answer 1

Let v₁ and v₂ be the frequencies of the sitar wire and the tabla membrane respectively. Since in this case 4 beats/s are heard,

v₁ = v₂ ± 4

On tightening the tabla membrane, its frequency increases. Now there are two possibilities :

(i) If v₁ < v2 , the number of beats increases on tightening the membrane.

(ii) If v₁ > v₂ , the number of beats decreases on tightening the membrane.