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Waves and Sound — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsWaves and Sound1 Mark
MCQ
A source and an observer are moving towards each other with a speed equal to $\frac{v}{2}$ where $v$ is the speed of sound. The source is emitting sound of frequency $n$. The frequency heard by the observer will be
  • A
    Zero
  • B
    $n$
  • C
    $\frac{n}{3}$
  • ✓
    $3 n$
✓

Answer

Correct option: D.
$3 n$
(d)$n^{\prime}=n\left(\frac{v+v_0}{v-v_s}\right)=n\left(\frac{v+v / 2}{v-v / 2}\right)=3 n$

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