Final answer:
The sound level for a noise with an intensity of 9.9 × 10-5 watts/m2 is approximately 79.95 dB, which can be rounded up to 80.00 dB.
Step-by-step explanation:
To find the sound level in decibels (dB) for a noise with an intensity of 9.9 × 10-5 watts/m2, we can use the formula for sound level in decibels, which is:
ß = 10 × log10(I/I0)
where ß is the sound level in decibels, I is the sound intensity in watts per meter squared, and I0 is the reference sound intensity, commonly taken as 10-12 W/m2 (the threshold of hearing).
Substituting the given values into this formula, we get:
ß = 10 × log10(9.9 × 10-5 W/m2 / 10-12 W/m2)
ß = 10 × log10(9.9 × 107)
ß = 10 × (log109.9 + 7)
ß ≈ 10 × (0.995 + 7)
ß ≈ 10 × 7.995
ß ≈ 79.95 dB
Therefore, we can round up and say that the correct answer is C. 80.00 dB.