A pipe of length 85 cm is closed from one end.Find the number of possible natural oscillations of air columm in the pipe whose frequencies lie bnelow 1250 Hz.The velocity of sound in air is 340 `m//s`.

Options

A. `12`
B. `8`
C. `6`
D. `4`

Answer

C

Explanation

For closed organ pipe `f = ((2n + 1)v)/(4l), (n = 0,1,2"……..")`
`((2n + 1)v)/(4l) lt 1250`
`(2n + 1) lt 1250 xx (4 xx 0.85)/(340)`
`(2n + 1) lt 12.5`
`2n lt 11.50`
`n lt 5.25`
So `n = 0, 1, 2, 3"………"5`
So we have `6` possibileties