Properties of sound
A sound wave is a mechanical wave (or mechanical vibration) that transit through media such as gas (air), liquid (water), and solid (wood).
Quality Of Sound
A sound or a sound wave is defined as the energy produced due to the vibrations of particles in a medium. When any medium produces a disturbance or vibrations, it causes a movement in the air particles which produces sound waves. Molecules in the air vibrate about a certain average position and create compressions and rarefactions. This is called pitch which is defined as the frequency of sound. The frequency is defined as the number of oscillations in pressure per second.
Categories of Sound Wave
People perceive sound in different ways, like a medico student takes sound as vibration produced by objects reaching the human eardrum. A physicist perceives sound as vibration produced by an object, which produces disturbances in nearby air molecules that travel further. Both of them describe it as vibration generated by an object, the difference is one talks about how it is received and other deals with how it travels and propagates across various mediums.
![### Sound Intensity and Echoes
**Question 11:** If 1 bug makes a sound of 8 dB, then what will 25 bugs sound like?
**Question 12:** If 4 bugs make a sound of 14 dB, then what will 25 bugs sound like?
**Question 13:** Explain echoes.
### Answer Structure
1. **Understanding Sound Intensity:**
- Sound intensity is measured in decibels (dB).
- The decibel scale is logarithmic, meaning that each incremental increase represents a tenfold increase in sound intensity.
2. **Calculating the Sound of Multiple Sources:**
- To calculate the combined sound intensity of multiple sources, we need to understand how decibels add up due to the logarithmic nature of the scale.
- **Formula for Combined Sound Intensity:**
If \( L_1 \) and \( L_2 \) are the sound levels in decibels for two separate sound sources, the total sound level \( L_{total} \) can be calculated using:
\[ L_{total} = 10 \cdot \log_{10}(10^{L_1/10} + 10^{L_2/10}) \]
3. **Example Calculation for Question 11:**
- **Given:** 1 bug = 8 dB
- **Find:** Sound intensity of 25 bugs.
Combining the sound of 25 identical sources, each at 8 dB:
\[ L_{total} = 10 \cdot \log_{10}(25 \cdot 10^{8/10}) \]
\[ L_{total} \approx 10 \cdot \log_{10}(25 \cdot 6.3096) \]
\[ L_{total} \approx 10 \cdot \log_{10}(157.74) \]
\[ L_{total} \approx 10 \cdot 2.198 \]
\[ L_{total} \approx 21.98 \ dB \]
4. **Example Calculation for Question 12:**
- **Given:** 4 bugs = 14 dB
- **Find:** Sound intensity of 25 bugs.
First, find the sound intensity per bug:
\[ L_1 = 14 \ dB](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fe822ee96-b072-4314-a719-51b641a0dd5d%2F40ab66bb-2661-48a5-a8d9-36e211d7df89%2Fb6w58gp_processed.jpeg&w=3840&q=75)
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