An air column in a pipe of length 1 m and closed at one end, will be in resonace with a vibrating tuning fork of frequency 250 Hz, if the length of the column is
[v = 330 m/s]

Options

A. `33 cm, 66 cm`
B. `33 cm , 99 cm `
C. `16.5 cm, 33 cm`
D. `33 cm , 132 cm`

Answer

B

Explanation

For a closed pipe,
`f = n (v/(4L)) " where " n = 1,3,5,....`
` :. L = (nv)/(4f) `
`:. " For " n = 1, L_(1) = (330 xx 100)/(4 xx 250) = 33 ` cm
`n = 2, L_(2) = 66` cm
` n = 3, L_(3) = 99` cm
` n= 4, L_(4) = 132` cm,......, etc.
Thus , the possible lengths are 33 cm and 99 cm as `L_(2) " and " L_(4)` are not possible.