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A 5-watt source sends out waves in air a...

A 5-watt source sends out waves in air at frequency 1000 Hz. Deduce the intensity at a 100-m distance, assuming spherical distribution. If `v= 350 m s^(-1)` and `rho= 1.3 kg m^(-3)`, deduce the displacement amplitude.

Text Solution

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`I=("power")/("area")=("power")/(4pi r^2)`
`I=(5)/(4pi(100)^2)=4xx10^(-5)Wm^(-2)`
`I=2pi^2 f^2 A^2 rho v`
`A=(1)/(pi f)sqrt((I)/(2rho v))`
`A=(1)/(3.14xx1000)sqrt((4xx10^(-5))/(2xx1.3xx350))=6.67xx10^(-8)` m
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