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A detector is released from rest over a source of sound of frequency $f = 10^3 \,\,Hz$. The frequency observed by the detector at time $t$ is plotted in the graph. The speed of sound in air is $(g = 10 \,\,m/s^2)$ ... $m/s$
An observer is riding on a bicycle and moving towards a hill at $18\,km\,h ^{-1}$. He hears a sound from a source at some distance behind him directly as well as after its reflection from the hill. If the original frequency of the sound as emitted by source is $640\,\,Hz$ and velocity of the sound in air is $320\,m / s$, the beat frequency between the two sounds heard by observer will be $...Hz$.
A string of length $1 \mathrm{~m}$ and mass $2 \times 10^{-5} \mathrm{~kg}$ is under tension $\mathrm{T}$. when the string vibrates, two successive harmonics are found to occur at frequencies $750 \mathrm{~Hz}$ and $1000 \mathrm{~Hz}$. The value of tension $\mathrm{T}$ is. . . . . . .Newton.
The transverse displacement in a streched string is given by
$y = 0.06 \sin \, \left( {\frac{{2\pi }}{3}x} \right)\cos \,(120\pi t)$
where $x$ and $y$ are in $m$ and $t$ is in $s$. The length of the string is $1.5\, m$ and its mass is $3.0 \times 10^{-2} \,kg$, then tension in string is ..... $N$
In an experiment with sonometer when a mass of $180\,g$ is attached to the string, it vibrates with fundamental frequency of $30\,Hz$. When a mass $m$ is attached, the string vibrates with fundamental frequency of $50\,Hz$. The value of $m$ is $.........\,g$.
Speed of a transverse wave on a straight wire (mass $6.0\; \mathrm{g}$, length $60\; \mathrm{cm}$ and area of cross-section $1.0\; \mathrm{mm}^{2}$ ) is $90\; \mathrm{ms}^{-1} .$ If the Young's modulus of wire is $16 \times 10^{11}\; \mathrm{Nm}^{-2},$ the extension of wire over its natural length is
Ten tuning forks are arranged in increasing order of frequency in such a way that any two consecutive tuning forks produce $4$ beats per second. The highest frequency is twice that of the lowest. Possible highest and lowest frequencies (in $Hz$ ) are ................
A person standing at a distance of $6\,\, m$ from a source of sound receives sound wave in two ways, one directly from the source and other after reflection from a rigid boundary as shown in the figure. The maximum wavelength for which, the person will receive maximum sound intensity, is .... $m$
$S_1$ and $S_2$ are two identical sound sources of frequency $656 \ Hz$. The source $S_1$ is located at $O$ and $S_2$ moves anti$-$clockwise with a uniform speed $4 \sqrt{2} \ ms ^{-1}$ on a circular path around $O$, as shown in the figure. There are three points $P, Q$ and $R$ on this path such that $P$ and $R$ are diametrically opposite while $Q$ is equidistant from them. A sound detector is placed at point $P$. The source $S_1$ can move along direction $O P.[$Given: The speed of sound in air is $324 \ ms ^{-1} ]$
$(1)$ When only $S_2$ is emitting sound and it is $Q$, the frequency of sound measured by the detector in $Hz$ is $. . . . .$
$(2)$ Consider both sources emitting sound. When $S_2$ is at $R$ and $S_1$ approaches the detector with a speed $4 \ ms ^{-1}$, the beat frequency measured by the detector is $Hz$.