QJEEM18Phe037: JEE Main 2018 Physics - Class 11 JEEM18Phe037 Solution: A tuning fork vibrates with frequency 256 H z and gives one…

Question

Verified Solution • 2025–26 Session moderate

A tuning fork vibrates with frequency

256

H z

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 =

\frac{N υ}{2 ℓ}

Here n = 255 Hz

N = 3

υ

= 340 m/s

∴

255 =

\frac{3 \times 340}{2 \times ℓ}

\Rightarrow

ℓ

=

\frac{3 \times 340}{2 \times 255} = 2 m

∴

ℓ

= 2m or 200 cm

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