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NEET Sample Paper NEET Sample Test Paper-54

  • question_answer
    The velocity of the sound in a stationary medium is 'a'. A sound source is moving with a velocity 'b' toward a stationary observer. If the frequency of sound sources is n, then the fractional change in the frequency as heard by the observer is-

    A) \[\frac{a}{a-b}\]                        

    B) \[\frac{b}{a-b}\]

    C) \[\frac{a}{b}\,n\]                                   

    D) \[\frac{a+b}{a}\,\]

    Correct Answer: B

    Solution :

    \[n'=n\,\left( \frac{V}{V-{{V}_{S}}} \right)\] \[\Delta n\,\,=\,\,n'-n\] \[=\,\,\,n\frac{V}{v-{{v}_{s}}}-n\] \[=\,\,\,n\left( \frac{{{V}_{S}}}{V-{{V}_{S}}} \right)\] \[\frac{\Delta n}{n}\,\,=\,\,\frac{b}{a-b}\]


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