Practice question

**Charging capacitor** conduction current in wires equals displacement current between plates because dQ/dt = I_c = ε₀ A dE/dt = ε₀ dΦ_E/dt = I_d, preserving charge conservation, magnetic field between plates due to I_d, same as that due to conduction current. In a capacitor, the displacement current i_d equals the conduction current in the connecting wires, so i_d = (dQ/dt) = 1.2 A . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 1.2 A, illustrating EM wave transverse nature and Maxwell's displacement current concept.