In one metre long open pipe what is the harmonic of resonance obtained with a tuning fork of frequency 480 Hz

Options

A. First
B. Second
C. Third
D. Fourth

Answer

C

Explanation

For an open pipe or length l, the frequency v is given by

`v=v'.(v)/(2l)`
where v is velocity of sound, v' the overtone.
Given, v = 480 Hz, l = 1 m
v = 330 m/s
`v'=(n(2l))/(v)`
`=(480xx2xx1)/(330)=2.9~~3`
Hence, this is the second overtone or third harmonic.