Question

Three source of sound of equal intensities have frequencies 251, 252 and 253 Hz respectively. When sounded together, the number of beats heard per second will be

• A. 3
• B. 2
• C. 1
• D. none of thesr

Answer 1

The correct option is C 1

$f_1=251$, $f_2=252$, $f_3=253$,

$F_1=\delta f_{1,2}=\delta f_{2,3}=1Hz$,

$F_2=\delta f_{1,3}=2Hz$

observed beat brequency,

$F_2-F_1=1Hz$

option "C" is correct.