Question 195: 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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