Practice question
Question
An electromagnetic wave in vacuum has an electric field amplitude of \( 30 \, \text{V/m} \). What is
the magnetic field amplitude? (Given \( c = 3 \times 10^8 \, \text{m/s} \))
Explanation
**Relationship E and B** in EM wave E₀ = c B₀, B₀ = E₀/c, for vacuum. Fields sustain each other via Maxwell's equations ∇×E = -∂B/∂t, ∇×B = μ₀ ε₀ ∂E/∂t, time-varying E produces B and vice versa, self-sustaining propagation without medium, speed c. Using B₀ = (E₀/c) , we have B₀ = (30/3 × 10⁸) = 1 × 10⁻⁷ T . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 1 × 10⁻⁷ T, illustrating EM wave transverse nature and Maxwell's displacement current concept.
Discussion
Comments
Please log in to join the discussion.
Login to commentNo comments yet. Be the first to start the discussion.