Question

The intensity I (in watts per square meter) of a television signal at a distance of k kilometers is described by the equation I =180/d^2. Find the intensity if the signal at a distance of 5 kilometers.

Answer 1

3.6 x 10^-5 watts per m²

1) Since the formula of the intensity of a beam of light, is

`I=(k)/(d^2)\Rightarrow I=(180)/(d^2)`

2) And the distance given is 5 km, then we need to convert that to meters 5 km=5000 meters then we can write:

`\begin{gathered} I=(180)/(5000^2) \\ I=3.6*10^(-5) \end{gathered}`

3) Then the Intensity of that TV 3.6 x 10^-5 watts, per m²