Electromagnetic Waves NEET MCQs

Maxwell-Ampere law: ∮ B · dl = μ₀(I_c + ε₀dΦ_E/dt)

Displacement current: I_d = ε₀dΦ_E/dt = ε₀A(dE/dt)

Speed in vacuum: c = 1/√(μ₀ε₀) = 3.0 x 10⁸ m s^-1

Speed in medium: v = 1/√(με) = c/√(Kμ_r)

Field relation: E₀/B₀ = E/B = c in vacuum

Wave equation: E = E₀ sin(kz - ωt), B = B₀ sin(kz - ωt)

Wavelength-frequency: c = νλ, k = 2π/λ, ω = 2πν

Energy density: u = (1/2)ε₀E² + B²/(2μ₀), and average electric energy = average magnetic energy

Intensity: I = <S> = (1/2)ε₀cE₀² = (1/2)cB₀²/μ₀

Radiation pressure: p = I/c for perfect absorber, p = 2I/c for perfect reflector

Spectrum order: Radio > Microwave > Infrared > Visible > Ultraviolet > X-ray > Gamma ray by wavelength