A vibrating string of certain length l under a tension T reasonates with a mode corresponding to fir

English

Gujarati

Hindi

14.Waves and Sound

hard

A vibrating string of certain length $l$ under a tension $T$ reasonates with a mode corresponding to the first overtone (third harmonic) of an air column of length $75$ $cm$ inside a tube closed at one end. The string also generates $4$ beats per second when excited along with a tuning fork of frequency $n$. Now when the tension of the string is slightly increased the number of beats reduces to $2$ per second. Assuming the velocity of sound in air to be $340$ $m/s$, the frequency $n$ of the tuning fork in $Hz $ is

A

$344$

B

$336$

C

$117.3$

D

$109.3$

Solution

$n = \frac{{3v}}{{4l}} = \frac{{3 \times 340}}{{4 \times \frac{{75}}{{100}}}} = 340{\mkern 1mu} {\rm{\,Hz}}$

Shring Fork Beats

$340$ $344$ or $336$ $4$

$T \uparrow $ $2$

Standard 11

Physics

Share

Similar Questions

A standing wave exists in a string of length $150\ cm$ , which is fixed at both ends with rigid supports . The displacement amplitude of a point at a distance of $10\ cm$ from one of the ends is $5\sqrt 3\ mm$ . The nearest distance between the two points, within the same loop and havin displacment amplitude equal to $5\sqrt 3\ mm$ is $10\ cm$ . Find the maximum displacement amplitude of the particles in the string …. $mm$

hard

A tuning fork vibrating with a sonometer having a wire of length $20 \,cm$ produces $5$ beats per second. The beats frequency does not change if the length of the wire is changed to $21 \,cm$. The frequency of the tuning fork must be ………… $Hz$

medium

A pulse or a wave train travels along a stretched string and reaches the fixed end of the string. It will be reflected back with

easy

A string is rigidly tied at two ends and its equation of vibration is given by $y = \cos 2\pi \,t\sin \sin \pi x.$ Then minimum length of string is …. $m$

medium

A string $2.0\, m$ long and fixed at its end is driven by a $240\, Hz$ vibrator. The string vibrates in its third harmonic mode. The speed of the wave and its fundamental frequency is

medium

(JEE MAIN-2019)