Speed of sound in air is `320 m//s` . A pipe closed at one end has a length of `1 m` and there is another pipe open at both ends having a length of `1.6 m` . Neglecting end corrections, both the air columns in the pipes can resonate for sound of frequency

Options

A. `80 H_(Z)`
B. `240 h_(Z)`
C. `320 h_(Z)`
D. `400 H_(Z)`

Answer

D

Explanation

Closed pipe
fundamental frequency is
`f_(1) = (nu)/ (4l)= (320) / (4xx1) = 80 H_(Z)`
other frequencies are
`3 f_(1) : 5 f_(1)` etc. or `240 H_(Z)`, `400 H_(Z)` etc.
Open pipe fundamental frequency is
`f_(1) = (nu)/ (2l)= (320)/(2 xx 1.6) = 100 H_(Z)` Other frequencies are`f_(1) : 3 f_(1) : 4 f_(1)` etc . or `200 H_(Z)` , `300 H_(Z)` and `400 H_(Z)` etc. So, then resonate at `400 H_(Z)`.