Calculating Sound Levels in dB: How to Convert Intensity to Decibels

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In summary, to calculate dB with I, you can use the formula dB = 10log<sub>10</sub>(I/I<sub>0</sub>). The reference intensity in dB calculations is 10<sup>-12</sup> W/m<sup>2</sup>, which is the lowest level of sound that the human ear can detect. dB can be used to compare different types of sounds, but it measures intensity, not pitch or quality. There is no limit to the range of values for dB, as it is a logarithmic scale. To convert dB to a linear scale, use the formula I = I<sub>0</sub> 10<sup>(dB/10)</sup>.
  • #1
RedPhoenix
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Homework Statement



Calculate the sound level in decibels of a sound wave that has an intensity of 4.00u "W/m2.

Homework Equations



dB = 10log(I/Io)

The Attempt at a Solution



dB = 10log(4/1E-12) = 126.02 db

Book says 66db. It vaguely covers this topic, not sure if I had missed something or not.
 
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  • #2
That's 4.00 micro-watts per meter squared, or 4.00 * 10^-6 W/m^2. It isn't 4 W/m^2..
 
  • #3
ideasrule said:
That's 4.00 micro-watts per meter squared, or 4.00 * 10^-6 W/m^2. It isn't 4 W/m^2..


pft... I completely overlooked that. Its getting late!
 

Related to Calculating Sound Levels in dB: How to Convert Intensity to Decibels

1. How do I calculate dB with I?

To calculate dB with I, use the formula dB = 10log10(I/I0) where I is the intensity of the sound in watts per square meter and I0 is the reference intensity of 10-12 W/m2.

2. What is the reference intensity in dB calculations?

The reference intensity is the lowest level of sound that the human ear can detect, which is 10-12 W/m2.

3. Can I use dB to compare different types of sounds?

Yes, dB is a unit of measurement for sound intensity and can be used to compare different types of sounds. However, it should be noted that dB measures the intensity of sound, not the pitch or quality.

4. Is there a limit to the range of values for dB?

No, there is no limit to the range of values for dB. It is a logarithmic scale, so the values can range from -∞ to ∞ depending on the intensity of the sound.

5. How do I convert dB to a linear scale?

To convert dB to a linear scale, use the formula I = I0 10(dB/10) where I is the intensity in watts per square meter. This will give you the linear scale value of the sound intensity.

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