i have a problem i have been wrestling for past day. Radiowave transmitter on earth radiates sinusoidal waves with whole power of(adsbygoogle = window.adsbygoogle || []).push({}); 50kW. we have to presume that radiation is equally distributed to upper surface. And i have to find amplitude ofEandB100 kmfrom earth.

I derived equation that involvesPandE.P=E^2 * sigma0 * c

But thatPis probably power of one wave. And to get power of one wave I thought it is logical to divide whole P with semisphere with radii of 100 km.

and after that calculated E and got 3*10^-5 V/m, but book has different answer, after getting E it is easy to calculate B because B = E/c. any suggestions?

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# Electromagnetic waves

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