3- In a charge free region for which H=5 cos(10"t-6y)a, A/m =μo, &=&&,, σ =0, Find: a) J and D b) ε, 4- In a certain region with μ=μo, &= 6.250, σ =0, the magnetic field of an EM wave is H = 0.6 cos ẞx cos(107t)a, A/m Using Maxwell's equation, find: a) B b) E