A pipe of length 85 cm is closed one end. Find the number of possible natural oscillationsof air column in the pipe whose frequencies lie below 1250 Hz. The velocity of sound in air is 340 m/s.

Options

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

Answer

C

Explanation

Length of pipe =85 cm=0.85 cm
Frequency of oscillation of air column in closed organ pipe is given by,
`f=((2n-1)v)/(4L)impliesf=((2n-1)v)/(4L) le1250`
`implies((2n-1)times340)/(0.85 times4)le1250implies 2n-1 le 12.5 approx 6`