Simple question

Question

There are 100 cars in a motor match. If all the motors produce 100db noise level, the sound intensity level produced by one car at the same time is ___?

A)1db;  

B)15db;

C) 80db;

D)200db;

Answer 1

the decibel scale is logarithmic, not linear, meaning that

10 dB increase corresponds to a 10-fold increase in sound intensity

20 dB increase corresponds to a 100-fold increase in intensity

what that means for this scenario is that the sound level of 100 cars is 20 dB higher than the sound level of one car, so the end value here is

100 dB (total) - 20 dB (increase) = 80 dB (sound level of one car)

so the sound intensity level produced by one car is 80 dB