### Question Description

Assignment

• In any calculation question, you need to show you step-by-step calculations and unit for credits.

1. Can you use sound level meter to distinguish between a sound and a noise? Why?

2. Why high frequency noise is usually more annoying and damaging to human’s hearing than low frequency?

3. Why narrow frequency bands or pure tones of sound have more harmful effects to hearing than broadband noise, given two having the same sound power level?

4. Exposure to vibration can cause vibration white finger disease, also known as Raynaud's Syndrome. In addition to acceleration (meters / second2) that can be measured with accelerometers, what other parameters be used to monitor vibration exposure? List at least two.

5. If the lower limit of human hearing is 20 Hz and the speed of sound in air is 1100 ft/sec, what is the wavelength of the sound wave at a frequency of 20 Hz?

6. What’s different between sound pressure and sound pressure level? There are several different units used for sound pressure. Please list at least 4 different units

7. The pain threshold of sound to human is about 140 dB. Please convert 140 dB to the sound pressure and with 4 different units you list in question 6

8. There are two machines producing the following pairs of dB, what is the combined SPL for each pair?

Pair 1: 80 dB and 86 dB

Pair 2: 90 dB and 96 dB

Pair 3: 96 dB and 102 dB

Pair 4: 90 dB and 103 dB

9. in your own words, what change patterns can you conclude from the calculations in question 8? List at least two common patterns

10. You work as an EHS manager at ABC company. The boss asked you to determine if it is possible to relocate one of four machines in a room, so that workers can’t be exposed to more than 85 dB, and the company can save \$\$\$\$ for Hearing Conservation program. The boss also wants the rearrangement having highest productivity (unfortunately, the louder machine the higher productivity). The four machine can produce 75, 79, 81, and 83 dB, respectively.Show your calculation to your boss!

Do you need an answer to this or any other questions?