Physics 3 — Electricity & Magnetism

The payoff: light

continues from lesson 4 — values defined earlier in the course stay live here

A changing E makes B; a changing B makes E; the disturbance feeds itself and propagates at exactly c = 1/√(μ₀ε₀). Maxwell computed that speed, recognized the number, and discovered light was electromagnetic:

eps_{0} = 8.854 \cdot 10^{-12}

permittivity of free space (F/m)

c_{wave} = \frac{1}{\sqrt{\mu_{0} \cdot eps_{0}}}

2.998 \times 10^{8}

the speed his equations predicted (m/s)

✓ pass

\mathrm{abs}\left(c_{wave} - 299800000\right) < 1000000

it is the measured speed of light

Where next: Physics 4 leaves fields for heat and flow — thermodynamics and fluids.