Skip to content

#electromagnetic wave generation

2 public questions tagged with this topic.

What is the significance of Maxwell's displacement current in the context of electromagnetic waves?

**Displacement current** I_d = ε₀ dΦ_E/dt, Φ_E = ∫ E·dA electric flux (V·m), ε₀=8.85×10⁻¹² F/m, ensures continuity of current in charging capacitor where conduction current stops between plates, I_d equals conduction current in wires, 3 A conduction ⇒ 3 A displacement, maintaining Ampere's law ∮ B·dl = μ₀(I_c+I_d). The document explains that displacement current leads to the generation of a magnetic field from a changing electric field, which, combined with Faraday's law, results in the propagation of electromagnetic waves. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification

Ref: NCERT > Physics Book > Electromagnetic Waves > Displacement Current and Ampere-Maxwell Law

Which of the following cannot produce electromagnetic waves?

**Hertz experiment** used induction coil connected to two rods with gap, spark produced oscillating charge, emitted EM wave, received by loop with gap sparking when E induced, measured wavelength by standing wave, demonstrated EM wave properties, validating Maxwell. Electromagnetic waves are produced by accelerated charges. Stationary charges produce only electrostatic fields, not time-varying fields required for EM waves. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields A charge moving with uniform velocity, illustrating EM wave transverse natu

Ref: NCERT > Physics Book > Electromagnetic Waves > Production of EM Waves and Hertz Experiment