Velocity of sound in air is `320 m//s`. The resonant pipe shown in Fig. 7.81 cannot vibrate with a sound of frequency .

Options

A. `80 Hz`
B. `240 Hz`
C. `320 Hz`
D. `400 Hz`

Answer

C

Explanation

` f = (v)/( 4 l) = (320)/( 4) Hz = 80 Hz`
Since even harmonics cannot be present therefore `320 Hz`
`(= 4 xx 80)` is ruled out.