the equation of a sound wave is y=0.0015sin(62.4x+316 t).find the wavelength of this wave
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Answer:
PHYSICS
The pressure variation in a sound wave in air is given by
ΔP=12sin(8.18x−2700t+π/4)N/m
2
Find the displacement amplitude. Density of air = 1.29kg/m
3
Give answer in terms of 10
−5
m
December 20, 2019avatar
Abhisri Waswani
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ANSWER
Given - ΔP=12sin(8.18x−2700t+π/4) ,
comparing this equation with , ΔP=Δp
m
sin(kx−ωt+ϕ) ,
we get , Δp
m
=12Pa ,
ω=2700 ,
or 2πf=2700 ,
or f=2700/2π
and k=8.18 ,
or 2π/λ=8.18 ,
or λ=2π/8.18 ,
therefore v=fλ=
2π
2700
.
8.18
2π
=330m/s
The relation between pressure amplitude Δp
m
and displacement amplitude A (maximum value of displacement ) is given by ,
Δp
m
=(vdω)A ,
where v= speed of sound in air ,
d= density of medium (air) ,
ω= angular frequency ,
given v=330m/s,d=1.29kg/m
3
,ω=2700rad/s,Δp
m
=12Pa ,
now Δp
m
=(vdω)A ,
or A=
vdω
Δp
m
=
330×1.29×2700
12
=1.04×10
−5
m