In: Physics
The average intensity of a particular TV station
The intensity of the signal, I = 3.0 * 10-13 W/m2
The Diameter, D = 70 cm = 0.77 m
So radius, r = 0.385 m
Area, A = ?r2 = 0.4657 m2
Power, P = IA = 0.4657*3 * 10-13 = 1.3971*10^-13 W
a)
Time, t = 7 hours = 14400 s
Energy = power * time = 2.012 * 10-9 J
b) The amplitude of electric field is
Emax = ?[2c?o I]
= ?[2(3.0 x10^8 m/s)(4? x 10^-7 H/m)(3.0 x10^-13 W/m2)]
= 1.504 x10^-5 V/m
The amplitude of magnetic field is
Bmax = Emax/c
= ( 1.504 x10^-5 V/m)/(3.0 x10^8 m/s)
= 5.013 x10^-14 T