A sound source is releasing a signal of constant frequency 330 Hz. f& $λ$ are frequency and wavelength observed by an observer. The velocity of sound in air is 330 $m s^{- 1}$ .
Column-I Column-II
P The observer & source move towards each other. 1 $λ = 1 m, f > 330 Hz$
Q
The observer and source are stationary, wind is
blowing towards source from observer.
2 $λ = 1 m, f = 330 Hz$
R
The source is stationary, wind is blowing from source to
observer and observer is moving away from the source.
3 $λ < 1 m, f > 330 Hz$
S
The source is stationary and observer is moving
towards source.
4 $λ = 1 m, f < 330 Hz$

Question

A sound source is releasing a signal of constant frequency 330 Hz. f& $λ$ are frequency and wavelength observed by an observer. The velocity of sound in air is 330 $m s^{- 1}$ .

Column-I		Column-II
P	The observer & source move towards each other.	1	$λ = 1 m, f > 330 Hz$
Q	The observer and source are stationary, wind is blowing towards source from observer.	2	$λ = 1 m, f = 330 Hz$
R	The source is stationary, wind is blowing from source to observer and observer is moving away from the source.	3	$λ < 1 m, f > 330 Hz$
S	The source is stationary and observer is moving towards source.	4	$λ = 1 m, f < 330 Hz$

Infinity Learn · Accepted Answer

λ$$=vf=330330=1mP$$ : As source and observer are moving towards each other f′$$=f0u+u0u-usFrequency$$ increases and wavelength decreases.Q : As source and observer are at rest $$vO=0$$ and $$vS=0$$ wind is blowing from source to observer moving away from $$source=$$ f′$$=f0u+uw+u0u+uw-us=f0Frequency$$ remain same and wavelength also remain same.R : Observer is moving towards stationary $$source=$$  f′$$=f0u+uw-u0u+uwFrequency$$ decreases and wavelength remain same.S :  f′$$=f0u+u0uFrequency$$ increases and wavelength remain same.

Doppler's effect

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