An observer is approaching with a speed $v$ towards a stationary source emitting sound waves of wavelength $\lambda_0$. The wavelength shift detected by the observer is (Take $c$ as the speed of sound).

An observer starts moving with uniform acceleration $a$ toward a stationary sound source emitting a whistle of frequency $n$. As the observer approaches the source,the apparent frequency $n'$ heard by the observer varies with time $t$ as:

Two sources $A$ and $B$ are sounding notes of frequency $660 \, Hz$. $A$ listener moves from $A$ to $B$ with a constant velocity $u$. If the speed of sound is $330 \, m/s$,what must be the value of $u$ so that he hears $8$ beats per second?

$A$ train is approaching a platform with a speed of $10 \,ms^{-1}$ while blowing a whistle of frequency $340 \,Hz$. What is the frequency of the whistle heard by a stationary observer on the platform (in $\,Hz$)? (Given speed of sound $= 340 \,ms^{-1}$)

$A$ car sounding its horn at $480\,Hz$ moves towards a high wall at a speed of $20\,m/s$. If the speed of sound is $340\,m/s,$ the frequency of the reflected sound heard by the passenger sitting in the car will be the nearest to ..... $Hz$.

$A$ train sounding a whistle of frequency $510 \,Hz$ approaches a station at $72 \,km/hr$. The frequency of the note heard by an observer on the platform as the train $(1)$ approaches the station and then $(2)$ recedes from the station are respectively (in hertz) (velocity of sound in air $= 320 \,m/s$).