91Ó°ÊÓ

The speed of sound is \(v = 344\;{\rm{m/s}}\).

The speed of the source is \({v_s} = 10\;{\rm{m/s}}\)

The speed of the observer is zero.

The Doppler shift is the shift in actual frequency and the apparent frequency due to relative motion between the source and the listener.

The apparent frequency from Doppler Effect is,

\(\begin{array}{c}f' = f\left( {\frac{{v - {v_o}}}{{v - {v_s}}}} \right)\\\frac{{f'}}{f} = \left( {\frac{{v - {v_o}}}{{v - {v_s}}}} \right)\end{array}\)

Now, plugging the values,

\(\begin{array}{c}\frac{{f'}}{f} = \left( {\frac{{344 - 0}}{{344 - 10}}} \right)\\\frac{{f'}}{f} = \frac{{344}}{{334}}\\\frac{{f'}}{f} = 1.0299\end{array}\)

The shift is,

\(\begin{array}{c}\frac{{f' - f}}{f} \times 100\% \\ = \left( {\frac{{f'}}{f} - 1} \right) \times 100\% \\ = \left( {1.0299 - 1} \right) \times 100\% \\ = 2.99\% \end{array}\)