Maxwell's equations predict the existence of which phenomenon?

• A. Quantum tunneling
• B. Black holes
• C. Neutrino oscillations
• D. Electromagnetic waves

Answer: (D)

Maxwell's equations show that time-varying electric and magnetic fields can sustain each other and propagate through space as waves. In free space, combining the curl equations leads to a wave equation for the electric field, ∇^2 E = μ0 ε0 ∂^2 E/∂t^2, which describes waves traveling at the speed c = 1/√(μ0 ε0). This predicts electromagnetic waves—radiation that can move through vacuum with E and B fields oscillating perpendicular to each other and to the direction of travel. The other phenomena listed—quantum tunneling, black holes, and neutrino oscillations—arise from quantum mechanics, general relativity, or particle physics, not from classical electromagnetism. So the phenomenon Maxwell's equations predict is electromagnetic waves.