The length of the string of a musical instrument is $90 \;cm$ and has a fundamental frequency of $120 \;Hz$. Where (In $cm$) should it be pressed to produce fundamental frequency of $180 \;Hz ?$
A$80$
B$75$
C$60$
D$45$
NEET 2020, Medium
Download our app for free and get started
C$60$
c Frequency of stretched string
$n =\frac{1}{2 \ell} \sqrt{\frac{ T }{ m }}$
If $T$ and $m$ are constant
$n \propto \frac{1}{\ell}$
$\frac{ n ^{\prime}}{ n }=\frac{\ell}{\ell^{\prime}}$
$\frac{180}{120}=\frac{90}{\ell}$
$\ell=60 cm$
Download our app
and get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
A wave in a string has an amplitude of $2\,\, cm.$ The wave travels in the $+ve$ direction of $x-$ axis with a speed of $128\,\, m/s$ and it is noted that $5$ complete waves fit in $4\,\, m$ length of the string. The equation describing the wave is
A train moves towards a stationary observer with speed $34 m/s$. The train sounds a whistle and its frequency registered by the observer is ${f_1}$. If the train’s speed is reduced to $17\, m/s$, the frequency registered is ${f_2}$. If the speed of sound is 340 m/s then the ratio ${f_1}/{f_2}$ is
A wire of density $8 \times 10^3\,kg / m ^3$ is stretched between two clamps $0.5\,m$ apart. The extension developed in the wire is $3.2 \times 10^{-4}\,m$. If $Y =8 \times 10^{10}\,N / m ^2$, the fundamental frequency of vibration in the wire will be $......\,Hz$.
A man stands in front of a hillock and fires a gun. He hears an echo after $1.5\, sec$. The distance of the hillock from the man is ...... $m$ (velocity of sound in air is $330\, m/s$)
A source of sound $S$ having frequency $f.$ Wind is blowing from source to observer $O$ with velocity $u$. If speed of sound with respect to air is $C,$ the wavelength of sound detected by $O$ is:
In a transverse wave the distance between a crest and neighbouring trough at the same instant is $4.0\, cm$ and the distance between a crest and trough at the same place is $1 .0\, cm$ . The next crest appears at the same place after a time interval of $0.4\,s$. The maximum speed of the vibrating particles in the medium is
The length of a sonometer wire is $0.75\, m$ and density $9 \times 10^3\, kg/m^3$. It can bear a stress of $8.1 \times 10^8\, N/m^2$ without exceeding the elastic limit. What is the fundamental frequency that can be produced in the wire .... $Hz$ ?
A transverse wave is given by $y = A\sin 2\pi \left( {\frac{t}{T} - \frac{x}{\lambda }} \right)$. The maximum particle velocity is equal to $4$ times the wave velocity when