Question

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

• A. $2$
• B. $1$
• C. $4$
• D. $3$

Answer 1

The correct option is A $2$

The formula for the beat frequency is $f_b=f_2-f_1$

Where $f_1$ and $f_2$ are the frequency of two waves.

Now

$f_b=f_2-f_1$

$f_b=(n+1)-(n-1)$

$f_b=(n+1-n+1)$

$f_b=2$

Thus the number of beats produced per second will be $2$.