The equation of a travelling sound wave is 
where 
is measured in 10-5 m, 
in second and 
in metre. (a) Find the ratio of the displacement amplitude of the particles to the wavelength of the wave. (b) Find the ratio of the velocity amplitude of the particles to the wave speed.
Given:
Equation of a travelling sound wave is 
, where 
is measured in 10−5 m
in second,
in metre.
Comparing the given equation with the wave equation, we find:
(a) We have:
⇒
So, required ratio:
(b) Let 
be the velocity amplitude of the wave.
Velocity 
⇒
Amplitude 
Wavelength: 
Time period: 
Wave speed: 
Required ratio
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