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#energy transport

2 public questions tagged with this topic.

What makes electromagnetic waves capable of carrying energy from one place to another?

**Energy in EM wave** equally divided between electric and magnetic fields, energy density u = ½ ε₀ E² + B²/(2μ₀) = ε₀ E² = B²/μ₀, average u_avg = ½ ε₀ E₀², intensity I = c u_avg = ½ c ε₀ E₀² = E₀ B₀/(2μ₀) = c B₀²/(2μ₀), radiation pressure p = I/c for absorption, 2I/c for reflection. The document highlights that electromagnetic waves carry energy due to their oscillating electric and magnetic fields, as seen in applications like radio signals. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Their oscillating electric and magnetic fields,

Ref: NCERT > Physics Book > Electromagnetic Waves > Energy, Intensity and Momentum of EM Waves

What physical principle explains why electromagnetic waves can carry energy over long distances?

**Poynting vector** S = E×B/μ₀ gives energy flow (W/m²), magnitude S = E B/μ₀, average = E₀ B₀/(2μ₀) = intensity, direction of propagation, showing energy transport perpendicular to E and B. The oscillating electric and magnetic fields of electromagnetic waves carry energy in the form of electromagnetic energy flux, described by the Poynting vector, enabling long-distance energy transfer. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Oscillating electric and magnetic fields, illustrating EM wave transverse nature and Maxwell's displacemen

Ref: NCERT > Physics Book > Electromagnetic Waves > Energy, Intensity and Momentum of EM Waves