posted by HelpPlease on .
If a large housefly 3 m away from you makes a noise of 43 dB, what is the noise level of 1200 flies at that distance, assuming interference has a negligible effect?
Noise level of 1200 flies = ??dB
HELP: Using the formula for decibels and the given information, you can calculate the ratio I / I0 for 1 fly.
HELP: If you assume that 1200 flies make 1200 times as much noise as 1 fly, what is I / I0 for 1200 flies?
1200 flies will have 1200 times the sound power or one at the same distance
10 log(10)1200 = 3.1 x 10 = 31 dB more than 43 db, or 74 dB
I don't understand the last hint.