A siren emitting a sound of frequency 800Hz moves away from an observer towards a cliff at a speed of 15ms−1. Then, the frequency of sound that the observer hears in the echo reflected from the cliff is (Take velocity of sound in air =330ms−1)
765Hz
800Hz
838Hz
885Hz
A
800Hz
B
765Hz
C
885Hz
D
838Hz
Open in App
Solution
Verified by Toppr
The general formula for apparent frequency is f′=v±uOv∓uSf
As observer is at rest so uO=0
Since the source moves towards cliff, i.e., effectively the source moves towards the observer (the sound being heard through echo), so uS taken as −uS=15m/s
Thus, f′=vv−uSf=330330−15800=838Hz
Was this answer helpful?
37
Similar Questions
Q1
A siren emitting a sound of frequency 800Hz moves away from an observer towards a cliff at a speed of 15ms−1. Then, the frequency of sound that the observer hears in the echo reflected from the cliff is (Take velocity of sound in air =330ms−1)
View Solution
Q2
A siren producing a sound of frequency 750Hz moves away from an observer at rest towards a cliff at a speed of 30m/s. The frequency of echo heard by the observer reflected from the cliff is [speed of sound in air =330m/s)
View Solution
Q3
A siren producing a sound of frequency 750Hz moves away from an observer at rest towards a cliff at a speed of 30m/s. The frequency of echo heard by the observer reflected from the cliff is
[speed of sound in air =330m/s)
View Solution
Q4
A siren emitting a sound of frequency 100 HZ moves away from you towards a cliff at a speed of 10m/s. The frequency of sound, you hear coming directly from the siren, is [take speed of sound in air =330m/s]
View Solution
Q5
A siren emits sound of frequency 1000Hz, it moves away from the observer towards a cliff with a speed of 10ms−1. Then, the frequency of sound heard by observer coming directly from the siren is :