contestada

A traveling electromagnetic wave in a vacuum has an electric field amplitude of 57.9 V/m. Calculate the intensity S of this wave. Then, determine the amount of energy U that flows through area of 0.0223 m 2 over an interval of 18.5 s, assuming that the area is perpendicular to the direction of wave propagation.

Respuesta :

ajeigbeibraheem

Answer:

Intensity S = 4.446 W/m²

Amount of Energy U = 1.834 J

Explanation:

Given that:

[tex]E_{max[/tex] = 57.9 V/m

Area A = 0.0223 m²

Time t = 18.5 s

Then; Intensity (S) = [tex]\frac{(E_{max})^2}{2 \ \mu_o \ C}[/tex]

where;

[tex]\mu_o = 4 \pi *10 ^{-7}[/tex]

[tex]C = 3*10^8[/tex]

∴ S = [tex]\frac{(57.9)^2}{2*(4 \pi *10^{-7})*(3*10^8 )}[/tex]

S = 4.446 W/m²

Energy flow U = S*A*t

U = 4.446×0.0223×18.5

U = 1.834 J