If the signal strength from an omnidirectional radio source is 100 mW at 10 meters,how strong will it be at 30 meters,ignoring absorptive attenuation?
A) about 30 mW
B) about 11 mW
C) about 4 mW
D) about 0.1 mW

Question

Quizplus · Accepted Answer

The signal strength decreases with the square of the distance from the source, according to the inverse square law. So, at 30 meters (3 times the distance), the strength is $ \frac{1}{3^2} = \frac{1}{9} $ of the original strength, which is approximately 11 mW.

If the Signal Strength from an Omnidirectional Radio Source Is