Solving Sound Intensities | W/m^2 and dB

In summary, the conversation is about solving two problems related to sound intensity. The first problem involves finding the intensity level of a sound given its intensity and the second problem involves using the inverse square law to find the intensity level of a siren at a certain distance. The person asking for help is advised to do some reading and look up the equations and concepts related to sound intensity.
  • #1
Huskies213
34
0
Can anyone help me with how you would solve these? i am lost...

1.) Soudn 1 has an intensity of 380 W/m^2. Sound 2 has an intensity level of 2.5 dB greater than the intensity level of soudn 1. What is the intensity level of sound 2?

2.) A siren produces a soudn of 120 dB at 2m. Find the intensity level of the siren at 12m.
 
Physics news on Phys.org
  • #2
What have you tried to do so far?
 
  • #3
1) What is the definition of a decibel in regards to sound intensity?

2) What does this question have to do with the inverse square law?
 
  • #4
Re

Can anyone help ? I am lost
 
  • #5
You need to do some reading. I gave you two very large hints with the questions I asked you. Look up the equation for calculating decibels from the sound intensity. Also, look up the inverse square law.
 

1. What is the difference between sound intensity in W/m^2 and dB?

Sound intensity is a measure of the amount of sound energy that passes through a given area in a specified amount of time. It is measured in watts per square meter (W/m^2). dB, or decibel, is a unit used to measure the intensity of sound relative to a reference level. It is a logarithmic scale that is useful for comparing sound levels. While sound intensity is an absolute measure, dB is a relative measure that takes into account the sensitivity of human hearing.

2. How do you convert from W/m^2 to dB?

To convert from W/m^2 to dB, you can use the formula dB = 10 log (I/1x10^-12), where I is the sound intensity in W/m^2. This formula is based on the reference sound intensity of 1x10^-12 W/m^2, which is the threshold of human hearing. By taking the logarithm of the ratio between the sound intensity and the reference level, we can express the intensity in terms of decibels.

3. What is the 3dB rule in sound intensity?

The 3dB rule in sound intensity states that a change of 3 decibels represents a doubling or halving of sound intensity. This means that if the sound intensity increases by 3dB, the sound will be twice as intense. Similarly, a decrease of 3dB represents a halving of sound intensity. This rule is important in understanding the relative loudness of different sound levels.

4. How is sound intensity measured?

Sound intensity can be measured using a sound level meter, which consists of a microphone to capture the sound waves and a display to show the measured sound level in decibels. The microphone converts the sound waves into electrical signals, which are then amplified and displayed as a reading in dB. The measurement of sound intensity can also be done using mathematical calculations based on the distance from the sound source and the sound pressure level.

5. Can sound intensity be harmful to humans?

Yes, sound intensity can be harmful to humans if it exceeds certain levels. Prolonged exposure to high sound intensities can lead to hearing loss and other health issues. The Occupational Safety and Health Administration (OSHA) has set a limit of 90dB for an 8-hour workday to protect workers from noise-induced hearing loss. The maximum recommended exposure to sound levels above 140dB is only a few minutes before it can cause permanent hearing damage.

Similar threads

Sound dampened through an object
    • Introductory Physics Homework Help
Replies
23
Views
790
Max velocity of a vibrating loud speaker membrane given sound intensity
    • Introductory Physics Homework Help
Replies
4
Views
1K
Calculating τ by knowing I is proportional to A^2
    • Introductory Physics Homework Help
Replies
8
Views
2K
Ratio of Intensities of 2 sounds
    • Introductory Physics Homework Help
Replies
5
Views
2K
Sound intensity of a thunderbolt
    • Introductory Physics Homework Help
Replies
1
Views
829
Calculating the power output from a persons mouth
    • Introductory Physics Homework Help
Replies
3
Views
1K
Calculating Sound Intensity and Pressure Variation at a Distance
    • Introductory Physics Homework Help
Replies
4
Views
1K
Audio interference of sound waves from two speakers
    • Introductory Physics Homework Help
Replies
19
Views
3K
Sound Intensity (Level) - Hearing Aid
    • Introductory Physics Homework Help
Replies
5
Views
2K
Calculation for finding distance with regard to sound intensity
    • Introductory Physics Homework Help
Replies
18
Views
2K

Hot Threads

Recent Insights

Back
Top