Question

Consider a cell phone that emits electromagnetic radiation with a frequency of 1.0 GHz and with a power of 80 W.

(a) What is the electric field amplitude at a distance 1190 m away from the phone? Assume it radiates as a point source.

(b) If your ear is only about 10 cm from the source of radiation, what is the electric field amplitude at your ear as you use the phone? Again assume the phone radiates as a point source.

(c) If the phone can be turned on and stays transmitting for 2 h before discharging the battery, how much energy can be stored in the battery?

Answer 1

Given, emitted frequency = 1.0GHz Power radiated, p = 80w (6) have, Eman Average Poynting vector, sa 2 Mol toe Eman The distance em 7 = 1190 power radiated at a away from SX Atror from the phone is P = p to e Eman X 40 or 2 2P 47 82 x toc 2 x 80 41 x (1190) x 8.854x70\x3x108 3.385 1. Enau = 0.058 v/m () Given, so= 10 cm 0.10 m The electric field (amplitude) at at your ear is
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