Asingle sports fan is capable of yelling at an intensity level of 80 decibels from a given distance. if 10,000 similar fans were all yelling from the same distance, which of the following will be the closest to the observed intensity level?
(a) 84 decibels
(b) 120 decibels
(c) 160 decibels
(d) 320 decibels

The correct answer is part 'c' 160 dB

Explanation:

When noise levels of different intensities are superimposed the resultant intensity is given by the equation

where,

is the intensity of a general sound level

Since we have 10000 fans each producing sound of 80dB thus the resultant intensity is given using the above formula as

≈ 22¢

Explanation:

240 / 1000 = 0.240 kV

0.240 kV(2.5 A)(3 hr) = 1.8 kW•hr

1.8 kW•hr($0.12/kW•hr) = $0.216