Question

a radio antenna broadcasts a 1.0 MHz radio wav e with 21 kW of power. Assume that the radiation is emitted uniformly in all directions. What is the waves intensity 25 km from the antenna

Answer 1

`I=2.67* 10^(-6)\ W/m`

Step-by-step explanation:

Given that,

Frequency of a radio antenna is 1 MHz

Power, P = 21 kW

We need to find the the waves intensity 25 km from the antenna . The object emits intenisty evenly in all direction. It can be given by :

`I=(P)/(4\pi r^2)\\\\I=(21* 10^3)/(4\pi (25000)^2)\\\\I=2.67* 10^(-6)\ W/m`

So, the wave intensity 25 km from the antenna is
`2.67* 10^(-6)\ W/m`.