A sound source of frequency 600 Hz is moving towards an observer with velocity 20m/s. The speed of sound is 340m/s. The frequency heard by observer will bea)630.5hzb)30hzc)637.5hzd)63.5 HzCorrect answer is option 'C'. Can you explain this answer?

Question

Answer

F(s)/F(l) = [V+V(s)]/[V+V(l)]
V = velocity of sound = 340m/s
V(l) = velocity of listener = 0
F(l) = frequency heard by listener = ?
V(s) = velocity of source = -20m/s (because, it's source to listener)
F(s) = frequency of source = 600hz
By putting these values in the above formula and solving we get,
F(l) = 637.5 Hz.
Hence C is correct.

Answer

Given:
Frequency of sound source = 600 Hz
Velocity of sound = 340 m/s
Velocity of observer = 20 m/s
The frequency heard by observer = ?

Formula used:
The formula used to find the frequency heard by an observer when both the sound source and observer are in motion is given by:
f' = f ((v+u)/(v±vs))
where,
f' = Frequency heard by the observer
f = Frequency of sound source
v = Velocity of sound
u = Velocity of observer
vs = Velocity of sound in the medium

Calculation:
Given, f = 600 Hz
v = 340 m/s
u = 20 m/s
vs = v
Using the above formula,
f' = f ((v+u)/(v±vs))
f' = 600 ((340+20)/(340±340))
f' = 600 ((360)/(0))
As the denominator is zero, we use the positive sign in the denominator as the observer is moving towards the sound source.
f' = 600 x 360/340
f' = 637.5 Hz
Hence, the frequency heard by the observer is 637.5 Hz.

Therefore, the correct answer is option (c) 637.5 Hz.

Answer

Frequency heard by observer = apparent frequency= original frequency (V-Vobs) divided by V-Vs
V velocity of sound
Vobs Velocity of observer
Vs Velocity of source

Answer

[V+V(l)] /F(l) = [V+V(s)] /F(s)
V=velocity of sound =340m/s
V(l)=velocity of listener =0
F(l)=frequency heard by listener=?
V(s) =velocity of source=-20m/s(coz,it's source to listener)
F(s) =frequency of source=600hz

Answer

F=(340-20)/340*600
f=32/34*600
f= 637.5 Hz
hence option C is correct

Answer

How can you. tell
637.5hz
please. explain me
please help me

Answer

A)630.5hz

Answer

F(s)/F(l) = [V+V(s)]/[V+V(l)]
V = velocity of sound = 340m/s
V(l) = velocity of listener = 0
F(l) = frequency heard by listener = ?
V(s) = velocity of source = -20m/s (because, it's source to listener)
F(s) = frequency of source = 600hz
By putting these values in the above formula and solving we get,
F(l) = 637.5 Hz.
Hence C is correct.

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