The intensity level of a power mower at a distance of 1.0 m is 100 dB. You wake up one morning to find that four of your neighbors are mowing their lawn 20 m from your open bedroom window. What is the intensity level in your bedroom?
A) 80 dB
B) 104 dB
C) 400 dB
D) 50 dB
E) 40 dB

Question

Quizplus · Accepted Answer

The intensity level decreases by 20 dB for every tenfold increase in distance. At 20 m, the intensity level is 80 dB for one mower. With four mowers, the intensity level increases by 6 dB, resulting in 86 dB.

The Intensity Level of a Power Mower at a Distance