Embibe Experts Solutions for Chapter: Sound Waves, Exercise 3: Exercise-3

Two successive resonant frequencies in an open organ pipe are $1944$ and $2592 \mathrm{Hz}$. If the speed of sound in air $324{ \mathrm{m} \mathrm{s}}^{-1}$, The length of tube is $l$ then value of $4l$ is ?

Two tunning fork having frequency. $300\mathrm{Hz}$ & $305\mathrm{Hz}$ produce beat phenomena. Then how many beats produce in $1\sec$.

Two sitar strings $A$ and$B$ playing the note 'Dha' are slightly out of tune and produce beats of frequency $5\mathrm{Hz}$. The tension of the string $B$ is slightly increased and the beat frequency is found to decrease to $3\mathrm{Hz}$. What is the original frequency of $B$ if the frequency of $A$ is $427\mathrm{Hz}$ ?

A source of sound of frequency $256\mathrm{Hz}$ is moving rapidly towards a wall with a velocity of $5 \mathrm{m} {\mathrm{s}}^{-1}$. How many beats per second will be heard by the observer on source it self if sound travels at a speed of $330 \mathrm{m} {\mathrm{s}}^{-1}$?

A person going away from a factory on his scooter at a speed of $36 \mathrm{km} {\mathrm{hr}}^{-1}$ listens to the siren of the factory. If the actual frequency of the siren is $700 \mathrm{Hz}$ and a wind is blowing along the direction of the scooter at $36 \mathrm{km} {\mathrm{hr}}^{-1}$, If the observed frequency heard by the person is $f_0$ then $\frac{f_0}{170}$ is. (Given speed of sound $=340 \mathrm{m} {\mathrm{s}}^{-1}$)

A car has two horns having a difference in frequency of $180\mathrm{Hz}$. The car is approaching a stationary observer with a speed of $60{ \mathrm{m} \mathrm{s}}^{-1}$. Calculate the difference in frequencies in $\left(\mathrm{Hz}\right)$ of the notes as heard by the observer, if velocity of sound in air is $330 \mathrm{m} {\mathrm{s}}^{-1}$.

A train approaching a hill at a speed of $40 \mathrm{km} {\mathrm{h}}^{-1}$ sounds a whistle of frequency $580 \mathrm{Hz}$ when it is at a distance of $1 \mathrm{km}$ from a hill. A wind with a speed of $40 \mathrm{km} {\mathrm{h}}^{-1}$ is blowing in the direction of motion of the train. Find the distance (in $\mathrm{km}$) from the hill at which the echo from the hill is heard by the driver. (Velocity of sound in air$=1200 \mathrm{km} {\mathrm{h}}^{-1}$)

A train of length $l$ is moving with a constant speed $v$ along a circular track of radius$R$, the engine of the train emits a whistle of frequency $f_0$. If the frequency heard by a guard at the rear end of the train is $n{f}_0$ then$n$ is :