A cell phone transmits 2.0 W of power at 380 MHz in a spherical pattern.What is the rms value of the electric field on the electron in the receiving antenna,located 3.0 km away?

Question

Quizplus · Accepted Answer

We can use the formula:

E = sqrt[(P/(4πr^2))(120π)]

where P is the transmitted power (2.0 W), r is the distance from the transmitter to the receiving antenna (3.0 km or 3.0 x 10^3 m), and 120π is the impedance of free space.

Plugging in the values, we get:

E = sqrt[(2.0/(4π(3.0 x 10^3)^2))(120π)]
E = 2.6 x 10^-3 V/m (or 2.6 μV/m)

Therefore, the answer is D.

A Cell Phone Transmits 2