Waves - Result Question 77

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79. A source and an observer move away from each other, with a velocity of $10 m / s$ with respect to ground. If the observer finds the frequency of sound coming from the source as $1950 Hz$, then original frequency of source is (velocity of sound in air $=340 m / s$ )

======= ####79. A source and an observer move away from each other, with a velocity of $10 m / s$ with respect to ground. If the observer finds the frequency of sound coming from the source as $1950 Hz$, then original frequency of source is (velocity of sound in air $=340 m / s$ )

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/waves/waves—result-question-77.md (a) $1950 Hz$

(b) $2068 Hz$

(c) $2132 Hz$

(d) $2486 Hz$

[2001]

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Answer:

Correct Answer: 79. (b)

Solution:

  1. (b) According to Doppler’s effect

$ n^{\prime}=(\frac{v-v_0}{v-v_s}) n=(\frac{340-10}{340+10}) n=\frac{330}{350} \times 1950 $

$ ={ }^{`} 068 Hz $