Where Does the Intensity of Sound Waves Go in Complete Silence?

In summary, the conversation discusses the concept of intensity in relation to sound waves and destructive interference. It is explained that at the point of complete destructive interference, there will be no resultant wave propagation and therefore no intensity or sound. The concept of intensity is further clarified as a measure of energy transfer per unit area and terms like "lost" do not apply in this case. It is also mentioned that the air particles at the point of interference exchange momentum and raise each other's kinetic energy, but the resulting temperature increase is negligible.
  • #1
oreo
81
2
If we set two speakers far apart, giving identical sound waves having intensity of threshold of pain, in such a way that at midway between them, there is complete destructive interference. Would there any intensity of sound there in complete silence? If not, then where is "lost" intensity gone? Would that " silence" cause any pain?
 
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  • #2
Intensity is the rate at which a wave transfers energy per unit area. If there is complete destructive interference midway between the speakers, then there will be no resultant wave propagation there, so the rate of energy transfer also equals 0(silence). Intensity is a relation between the characteristic properties of a wave (in this case power and area), and as such terms like "lost" do not apply to it in this case. Since the waves cancel each other midway, you can say that the air particles simply exchange some momentum and raise each other's kinetic energy of vibration over there. Whether that silence causes discomfort or not is entirely up to the listener.
 
  • #3
Intensity is the rate at which a wave transfers energy per unit area. If there is complete destructive interference midway between the speakers, then there will be no resultant wave propagation there, so the rate of energy transfer also equals 0(silence). Intensity is a relation between the characteristic properties of a wave (in this case power and area), and as such terms like "lost" do not apply to it in this case. Since the waves cancel each other midway, you can say that the air particles simply exchange some momentum and raise each other's kinetic energy of vibration over there. Whether that silence causes discomfort or not is entirely up to the listener.
 
  • #4
PWiz said:
Intensity is the rate at which a wave transfers energy per unit area. If there is complete destructive interference midway between the speakers, then there will be no resultant wave propagation there, so the rate of energy transfer also equals 0(silence). Intensity is a relation between the characteristic properties of a wave (in this case power and area), and as such terms like "lost" do not apply to it in this case. Since the waves cancel each other midway, you can say that the air particles simply exchange some momentum and raise each other's kinetic energy of vibration over there. Whether that silence causes discomfort or not is entirely up to the listener.
So if they increase each other's kinetic energy then the temperature of that area should increase! Isn't it?
 
  • #5
By a negligible amount, yes.
 
  • #6
PWiz said:
By a negligible amount, yes.
Thanks for clarification
 
  • #7
If you shout for 8 years, the energy could heat up a cup of coffee. So you can imagine by how little the temperature will rise in this case.
 

1. What is sound intensity?

Sound intensity refers to the amount of energy that is transmitted through sound waves per unit of time. It is a measure of how loud or soft a sound is perceived to be.

2. How is sound intensity measured?

Sound intensity is typically measured in units of decibels (dB). A decibel is a logarithmic unit that compares the intensity of a sound wave to a reference level. The higher the decibel level, the louder the sound.

3. What factors affect the intensity of sound waves?

The intensity of sound waves can be affected by various factors such as the amplitude of the sound wave, distance from the sound source, and the medium through which the sound is traveling. Other factors include the frequency and direction of the sound wave.

4. How does sound intensity affect human hearing?

Exposure to high levels of sound intensity can cause damage to the ear and lead to hearing loss. The human ear has a limited range of sound intensity that it can handle without causing harm. Prolonged exposure to loud sounds can also cause temporary or permanent hearing loss.

5. Can sound intensity be manipulated or controlled?

Yes, sound intensity can be manipulated and controlled through various methods such as adjusting the distance from the sound source, using sound-absorbing materials, or using devices such as earplugs or noise-cancelling headphones. However, it is important to be aware of potential risks and to always protect one's hearing when exposed to loud sounds.

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