a mobile base in an urban environment has the power of 15 microW at 175 m. If the propagation follows an inverse cube power law, what is a reasonable power value in microWatt distance 0.7 km from base station

Power P at distance 0.7 km is: 0.234 µW

Explanation:

We know that

inverse cube-power law.

Thus Power, P = c / d³

Substituting we have

15 µW = c / (175 m)³

c = (15 µW) x (175 m)³

Then finally Power value at 0.7 km.

Will be

P = c / d³

P = ((15 µW) x (175 m)³) / (700 m)³

= (15 µW) x (175 / 700)³

= (15 µW) x (0.25)³

=(15 µW) x (0.015625)

P = 0.234 µW

answer; i do believe its (d) modem;

check the image attached

some main parts enter backspace caps lock shift and ctrl