An observer moves towards a stationary source | vedclass

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(B) The source of sound is stationary,so the wavelength of the sound waves emitted by the source remains unchanged as $\lambda$.The apparent frequency

Vedclass · Accepted Answer

$1.2f, \lambda$

Vedclass · Answer

(B) The source of sound is stationary,so the wavelength of the sound waves emitted by the source remains unchanged as $\lambda$.The apparent frequency $f'$ heard by an observer moving towards a stationary source is given by the Doppler effect formula:$f' = f \left( \frac{v + v_o}{v} \right)$where $v$ is the speed of sound and $v_o$ is the speed of the observer.Given that the observer moves with a speed $v_o = v/5$,we substitute this into the formula:$f' = f \left( \frac{v + v/5}{v} \right) = f \left( \frac{1.2v}{v} \right) = 1.2f$Since the source is stationary,the wavelength $\lambda$ does not change for the observer.Therefore,the apparent frequency is $1.2f$ and the wavelength is $\lambda$.

An observer moves towards a stationary source of sound with a speed $1/5^{th}$ of the speed of sound. The wavelength and frequency of the source emitted are $\lambda$ and $f$ respectively. The apparent frequency and wavelength recorded by the observer are respectively:

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