An electronically driven loudspeaker is placed near the open end of a resonance column apparatus. The length of air column in the tube is 80 cm. The frequency of the loudspeaker can be varied between 20 Hz and 2 kHz. Find the frequencies at which the column will resonate. Speed of sound in air `= 320 m s^-1`

Answer

A, B, C

Explanation

the resoN/Ance colun apparatus is equivalent to a closed organ pipe.
Here `I=80cm=80xx10^-2`
mv=320m/s`
`rarr n_0=v/(4I)=320/(4xx50x10^-2)=100Hz`
So the frequency of the other harmonies are odd multiple of `n_0`
`=(2n+1)100Hz`
According to the question the harmonic should be betwen 20 Hz nd2kHz`
So, n=(0,1,2,3,4,5,.....9)`