Question

Three sound waves of equal amplitudes have frequencies $(v-1),v,(v+1)$. They superpose to give beats. The number of beats produced per second will be

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

The correct option is B

$2$

Explanation:

1. The beat frequency is equal to the complete value of the alteration in the frequency of the two waves. The count of beats per second is equivalent to the difference in frequencies of two waves is called beat frequency.
2. Mathematically $\left|{\mathrm{f}}_2-{\mathrm{f}}_1\right|\mathrm{where}{\mathrm{f}}_2\mathrm{is}\mathrm{upper}\mathrm{frequency}\mathrm{and}{\mathrm{f}}_1\mathrm{is}\mathrm{lower}\mathrm{frequency}$
3. Beat produced between $(v-1)andvis1.$
4. Beat produced between $vandv+1is1.$
5. Beat produced between $(v-1)and(v+1)$ is between $(v-1)and(v+1)is2$.
6. Therefore, the number of beats produced per second will be $2$.

Hence, the correct option is (B).