What is the Doppler effect? Write its example and explain how its analysis can be performed.
(N/A) The Doppler effect is the phenomenon where the observed frequency of a wave changes due to the relative motion between the source of the wave and the observer.
Example: The pitch (or frequency) of the whistle of a fast-moving train appears to decrease as it recedes away from an observer. Conversely,when an observer approaches a stationary source of sound at high speed,the pitch of the sound heard appears to be higher than the actual frequency of the source.
Analysis: The Doppler effect is a wave phenomenon applicable to both sound and electromagnetic waves. We analyze the frequency changes under three primary conditions:
$(1)$ The observer is stationary,but the source is moving.
$(2)$ The observer is moving,but the source is stationary.
$(3)$ Both the observer and the source are moving relative to the medium.
Example: The pitch (or frequency) of the whistle of a fast-moving train appears to decrease as it recedes away from an observer. Conversely,when an observer approaches a stationary source of sound at high speed,the pitch of the sound heard appears to be higher than the actual frequency of the source.
Analysis: The Doppler effect is a wave phenomenon applicable to both sound and electromagnetic waves. We analyze the frequency changes under three primary conditions:
$(1)$ The observer is stationary,but the source is moving.
$(2)$ The observer is moving,but the source is stationary.
$(3)$ Both the observer and the source are moving relative to the medium.
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Similar Questions
$A$ source of sound emits waves with frequency $f \, Hz$ and speed $V \, m/s$. Two observers move away from this source in opposite directions,each with a speed $0.2V$ relative to the source. The ratio of frequencies heard by the two observers will be
Easy
View SolutionStatement $-1$: Due to the motion of the listener,the frequency of the sound waves (as received by the listener) emitted by a stationary source is affected.
Statement $-2$: Due to the motion of the source,the wavelength of the sound waves (emitted by the source) as received by a stationary listener is affected.
Statement $-3$: If the receiver and the source are both moving,the observed frequency must be different from the original frequency of the source.
Treat the motion of the source or listener as always along the line joining them for all the above cases.
Statement $-2$: Due to the motion of the source,the wavelength of the sound waves (emitted by the source) as received by a stationary listener is affected.
Statement $-3$: If the receiver and the source are both moving,the observed frequency must be different from the original frequency of the source.
Treat the motion of the source or listener as always along the line joining them for all the above cases.
Medium
View SolutionThe driver of a car travelling with a speed $V_1 \ m/s$ towards a wall sounds a siren of frequency $n \ Hz$. If the velocity of sound in air is $V \ m/s$,then the frequency of sound reflected from the wall and as heard by the driver,in $Hz$,is
An engine moving towards a wall with a velocity $50 \ m/s$ emits a note of $1.2 \ kHz$. The speed of sound in air is $350 \ m/s$. The frequency of the note after reflection from the wall as heard by the driver of the engine is: (in $kHz$)
DifficultKCET 2007
View SolutionAn engine sounding a whistle of frequency $1152 \ Hz$ is receding from a stationary observer at $72 \ km/h$. If the velocity of sound in air is $340 \ m/s$,then the frequency of the note heard by the observer is: (in $Hz$)
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