Question

For a sound wave travelling towards `+x` direction, sinusoidal longitudinal displacement `epsi` at a certain time is given as a function of `x` (Fig). If bulk modulus of air is `B=5xx10^5(N)/(m^2)`, the variation of pressure excess will be
A.
B.
C.
D.

Answer 1

Correct Answer - A
`epsi=Asin(kx-omegat)`
`P_(ex)=-B(depsi)/(dx)=-Bakcos(kx-omegat)`
Amplitude of `P_(ex)` is
`Bak=(5xx10^5)(10^-4)((2pi)/(0.2))`
`=5pixx10^2Pa`