Doppler effect, source and receiver in different media

In summary, the conversation discusses the calculation of the frequency of a sound wave emitted by a submarine and caught by a helicopter in different media. The use of the Doppler shift formula is questioned due to the change in wave speed between media. The question remains on how to account for this change and accurately calculate the received frequency.
  • #1
nikolafmf
114
0
Hello,

For convenience, we can say that a submarine at some depth in sea emits sound wave which refracts from the surface of the sea and is caught by a helicopter at some height above the sea. If we know the speeds of the submarine and the helicopter and the frequency of the emitted wave (and, of course, the speed of the sound in water and air), how are we going to calculate the frequency of the received wave? I know how to use the Doppler shift's formulas when the wave travels all the time in a same media. But, when it changes media, it also changes its speed. How can we account for that?


Nikola
 
Physics news on Phys.org
  • #2
Frequency is not afected by passing between media.
 
  • #3
A.T. said:
Frequency is not afected by passing between media.

Yes, I know that. But in the formula for Doppler effect, wave speed occurs, as in the first formula here: http://en.wikipedia.org/wiki/Doppler_effect#General. And speed do changes by passing between media. So, how can I calculate received frequency?
 

1. What is the Doppler effect?

The Doppler effect is the perceived change in frequency of a wave due to the relative motion of the source and the receiver. This effect is commonly observed in sound waves, such as the change in pitch of a siren as it approaches and then passes by an observer.

2. How does the Doppler effect affect the perception of sound in different media?

The Doppler effect is dependent on the speed of sound in a given medium. In a medium with a higher speed of sound, such as water, the perceived change in frequency will be less than in a medium with a lower speed of sound, such as air. This means that the pitch of a sound will change less in water than in air as the source and receiver move relative to each other.

3. Can the Doppler effect be observed in light waves?

Yes, the Doppler effect can also be observed in light waves. This is known as the redshift and blueshift effect, where the wavelength of light from a moving source appears longer (redshift) or shorter (blueshift) to an observer. This effect is commonly used in astronomy to measure the motion of stars and galaxies.

4. How does the Doppler effect impact the accuracy of measurements?

The Doppler effect must be taken into account when making precise measurements, such as in radar or sonar systems. Failure to account for the relative motion of the source and receiver can result in inaccurate measurements. In some cases, the Doppler effect can be used to improve accuracy, such as in Doppler radar for weather forecasting.

5. Can the Doppler effect be used to measure the speed of an object?

Yes, the Doppler effect can be used to measure the speed of an object by measuring the change in frequency of a wave emitted by the object. This is commonly used in police radar guns to measure the speed of moving vehicles. However, this method is dependent on the accuracy of the speed of sound in the medium and the angle of the object's motion relative to the source and receiver.

Similar threads

I Formula for Doppler effect in moving medium?
    • Classical Physics
Replies
16
Views
1K
I Classical waves and the Doppler shift
    • Classical Physics
Replies
5
Views
1K
B Help with understanding the Doppler effect
    • Classical Physics
2
Replies
64
Views
5K
I Dispersion Relation in Different Media
    • Classical Physics
Replies
3
Views
489
I Analog TV reception in a spacecraft moving relative to the Earth
    • Classical Physics
Replies
9
Views
647
Where Can I Find Doppler Effect Sound Samples for Specific Scenarios?
    • STEM Educators and Teaching
Replies
1
Views
1K
Range of frequency heard by observer related to Doppler effect
    • Introductory Physics Homework Help
Replies
8
Views
201
I Deriving Doppler Effect Frequency w/ Stationary Person & Moving Source
    • Mechanics
Replies
3
Views
707
Submarine communications and RF skin depth
    • Electrical Engineering
Replies
6
Views
218
Exploring the Doppler Effect: Frequency & Distance
    • Classical Physics
Replies
3
Views
2K

Hot Threads

Recent Insights

Back
Top