Observer A is at rest. Source `S_(1)` is moving towards observer A and source `S_(2)` is moving away from observer A. velocity of sound is `330(m)/(sec)`. `beta`= beat frequency heard per second by A. Approximate value of `beta` is:

Answer

2

Explanation

`beta=33((330)/(330-10)-(330)/(330+10))`
`=33(330(2xx10))/((330)^(2)-(10)^(2))`
if `(330)^(2)-(10)^(2)=(330)^(2)`
then `beta=33xx(20)/(330)=2Hz`