Question 157: Waves

Question

A tuning fork vibrates with frequency $256$ $Hz$ and gives one beat per second with the third normal mode of vibration of an open pipe. What is the length of the pipe ? (Speed of sound in air is $340\,m{s^{ - 1}}$)

Accepted Answer

The tuning fork vibrates with frequency 256 Hz and give one beat per second So,  the organ pipe will have frequency (256 $ \pm $ 1) Hr.
For open organ pipe,
Frequency n = ${{N\upsilon } \over {2\ell }}$
Here n = 255 Hz
N = 3
$\upsilon $ = 340 m/s
$	herefore\,\,\,\,$ 255 = ${{3 	imes 340} \over {2 	imes \ell }}$
$ \Rightarrow $$\,\,\,\,$  $\ell $  = ${{3 	imes 340} \over {2 	imes 255}} = 2\,m$
$	herefore\,\,\,\,$  $\ell $ = 2m or 200 cm

Answer

$220$ $cm$

Answer

$190$ $cm$

Answer

$180$ $cm$

Answer

$200$ $cm$

Waves

A tuning fork vibrates with frequency 256 Hz and gives one beat per second with the third normal mode of vibration of an open pipe. What is the length of the pipe ? (Speed of sound in air is 340\,m{s^{ - 1}})

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