# 8. A large explosion is heard by two people. The first is located 10 meters away and the second is located 40 meters away. By which factor is the intensity of the second observer compared to the first?

a.) 16
b.) 4
c.) 1/4
d) 1/16
e.) 1/900

Ever heard of the inverse square law? If "intensity" means power per area, the inverse square law applies. The second observer is four timnes farther away.

## To determine the factor by which the intensity of the second observer is compared to the first, we can use the inverse square law.

According to the inverse square law, the intensity of a sound or any other form of energy decreases with the square of the distance. This means that as the distance from the source doubles, the intensity decreases to one-fourth (1/4) of the original intensity.

In this case, the second observer is located four times farther away from the explosion than the first observer. Therefore, the intensity of the sound heard by the second observer would be 1/4 or one-fourth of the intensity heard by the first observer.

So, the correct answer is option c) 1/4.