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14.Waves and Sound
normal
A sound-source is moving in a circle and an observer is outside the circle at $O$ as shown in figure. If the frequencies as heard by the listener are $\nu _1, \nu _2$ and $\nu _3$ when the source is at $A, B$ and $C$ position, respectively, then
A
${\nu _1} = {\nu _2} > {\nu _3}$
B
${\nu _2} > {\nu _3} > {\nu _1}$
C
${\nu _1} > {\nu _2} > {\nu _3}$
D
${\nu _1} > {\nu _3} > {\nu _2}$
Solution
$\mathrm{n}^{\prime}=\mathrm{n}\left(\frac{\mathrm{v}}{\mathrm{v} \pm \mathrm{v}_{\mathrm{s}}}\right)$ for $\mathrm{n}_{\mathrm{A}}=\mathrm{n}\left(\frac{\mathrm{v}}{\mathrm{v}-\mathrm{v}_{\mathrm{s}}}\right)$
$\mathrm{n}_{\mathrm{B}}=\mathrm{n}\left(\frac{\mathrm{v}}{\mathrm{v}+\mathrm{v}_{\mathrm{s}}}\right)$
$\mathrm{n}_{\mathrm{C}}=\mathrm{n}$ (no dopler)
Standard 11
Physics
