9.36 Given the total electromagnetic energy + H+B) dy W- - (E D+H show from Maxwell's equations that aw at 49.37 In air, Ecos(12mx) sin(10" -ε (Ex H) dS- E-J dv ay)a, V/m. Find H and a. 9:38 An AM radio signal propagating in free space has E E, sin(1200πt - Bz)a, Determine ẞ and n. E₁ H = sin(1200mtßz)a, 11 9.39 An antenna radiates in free space and 12 sin H => cos(2 X 10"t - Br)a, mA/m T Find the corresponding E in terms of ẞ. Section 9.6-Time-Varying Potentials 9.40 In free space (p, =0,J = 0), show that A = Но (cos 8 a, sin a)-) 4πr Problems