A 100-kW radio station emits EM waves in all directions from an antenna on top of a mountain. What is the intensity of the signal at a distance of 10 km?
A. 8 × 10?5 W/m2
B. 8 × 10?6 W/m2
C. 3 × 10?3 W/m2
D. 0.8 W/m2
E. 2.5 × 10?5 W/m2
Answer: A
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