List of top Physics Questions on doppler effect asked in TS EAMCET

If a source of sound initially at rest is moving away from a stationery observer with an acceleration of $11~ms^{-2}$, then the time taken for the frequency of sound heard by the observer to become 10% less than the frequency of source is (Speed of sound in air $=330~ms^{-1}$)}

A source of sound of frequency $660\text{ Hz}$ and an observer are moving towards each other with speeds of $31\text{ kmph}$ and $23\text{ kmph}$ respectively. If the wind blows with a speed of $5\text{ kmph}$ from observer towards the source, then the frequency of the sound heard by the observer is: (Speed of sound in air $=340\text{ ms}^{-1}$)