Electrostatics AdvancedHardQuestion 31494
Question
The self-energy of a point charge (formal calculation) is:
- AZero
- Bkq²/r → 0 as r → 0
- CInfinite (divergent)Correct
- Dkq²/r₀ where r₀ is classical electron radius
Correct answer
Infinite (divergent)
Explanation
Self-energy = energy to assemble a point charge from infinity = ∫₀^∞ field energy = (½ε₀)(kq/r)² × 4πr²dr → diverges as r → 0. This UV divergence is a foundational problem in classical electrodynamics, resolved only in quantum field theory (renormalisation).