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#electric field amplitude

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EM Wave Characteristics - Transverse Nature and E/B Ratio

In electromagnetic wave theory, what is the relationship between the electric and magnetic field amplitudes in vacuum?

**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. The electric and magnetic field amplitudes are related by the speed of light in vacuum, where E₀ = B₀ c , or equivalently B₀ = (E₀/c) , ensuring energy balance in the wave. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields E₀ = B₀ c, illustrating EM wave transverse nature and Maxwell's displacement curr

Ref: NCERT > Physics Book > Electromagnetic Waves > EM Wave Characteristics - Transverse Nature and E/B Ratio

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EM Wave Characteristics - Transverse Nature and E/B Ratio

An electromagnetic wave in vacuum has a magnetic field amplitude of \( B_0 = 4 \times 10^{-8} \, \text{T} \). What is th

**EM wave in vacuum** transverse, E and B perpendicular to propagation and to each other, E×B along propagation, in phase, E/B = c =3×10⁸ m/s, c =1/√(μ₀ ε₀), μ₀=4π×10⁻⁷ H/m, ε₀=8.85×10⁻¹² F/m. For E₀=45 V/m, B₀=E₀/c=45/3×10⁸=1.5×10⁻⁷ T=150 nT, illustrating B much smaller than E. Using E₀ = B₀ c , we have E₀ = (4 × 10⁻⁸) × (3 × 10⁸) = 12 V/m . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 12 V/m, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > EM Wave Characteristics - Transverse Nature and E/B Ratio

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