Question

Describe how the doppler effect explains why a siren has a lower pitch as a fire engine moves away from you. How does the frequency of a wave relate to the energy of the wave? Write your answers out in your own words please :))

Answer 1

The Doppler effect is the change in sound or light that occurs whenever there is motion between the source and its observer. The siren of the fire engine has a lower pitch as it moves away because the waves are now spread out causing a lower frequency and a lower pitch. High-frequency sound waves have a higher pitch and higher energy than low-frequency waves. 

Answer 2

Answer:

Sirens lower pitch when the fire engine moves away:

When the fire engine(the source) moves away from the listener, there is a change or decrease in frequency, f of the sound produced by the fire engine.

Because, when there is a change in the distance, d between the listener and the source of the sound there is always a change in the frequency or the pitch of the sound. As the source of the sound comprises a given field in which the intensity of the sound produced is much more effective, then the person standing outside that field.

Source of the Sound, when the source is leaving:

• f₁=a/a+U,
• And the sound pitch will be low,  f₁∠f.

Sound source approaching towards the listener:

• fa=f×(a/a-U),

• And the pitch of the sound will be of high value as, f∠fa.

Explanation:

Doppler effect:

"The Doppler effect is the change in the frequency,f level between the listener and the source. As the difference between the intensity or level of frequency,f is due to the increase and decrease of the distance between the listener and the source."