Velocity of sound in air is `320 m s^(–1)`. A pipe closed at one end has a length of 1 m. Neglecting end correction, the air column in the pipe cannot resonate with sound of frequency

Options

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

Answer

A

Explanation

For a pipe closed at one end
`f = (nV)/(4l) " where " n = 1, 3, 5, ...`
For ` n = 1, f_(1) = V/(4l) = 320/(4l) = 320 /(4 xx 1) =80 ` Hz
For ` n = 3, f_(2) = 3f_(1) = 240 ` Hz
For `n = 5, f_(5) = 5f_(1) = 80 xx 5 = 400 ` Hz
Hence we cannot get resonance for 320 Hz.