Question

A radio antenna broadcasts a 1.0 MHz radio wave with 30 kW of power. Assume that the radiation is emitted uniformly in all directions. Part A What is the wave's intensity 33 km from the antenna? Express your answer in watts per meter squared. II = nothing W/m2 Request Answer Part B What is the electric field amplitude at this distance? Express your answer in volts per meter. EE = nothing V/m

Answer 1

Answer:

a) intensity  $= 2.19 \times 10^{-6} W/m^2$

b) E = 0.0406 V/m

Explanation:

given data:

Power =  30 kW

R = 33×10^3 M

1) Intensity is given as

$Intensity I = \frac{P}{4\times \pi \times r^2}$

$= \frac{30 \times 10^3}{4\times 3.14 \times (33\times10^3)^2}$

$= 2.19 \times 10^{-6} W/m^2$

2) electric field is given as

$I = 1/2 \times \epsilon \times c \times E^2$

Solving for E

$E = \sqrt{\frac{2I}{\epsilon c}}$

$E =\sqrt{\frac{2\times 2.19 \times 10^{-6}}{8.85\times 10^{-12} 3\times 10^8}}$

E = 0.0406 V/m