PX157 - A1 - introduction

elementary charge: $e \approx 1.6022 \times 10^{- 15} C$
the natural unit of charge - invariant and close to one of the basic S units, ie: $A = C s^{- 1}$
quantized, ie: $q = k e$ , $k \in Z$
total charge is conserved in an isolated system: $\sum_{i = 1}^{N} q_{i} = 0$
- eg: $n^{0} \to p^{+} + e^{-} + {\bar{ν}}_{e}$ , charge: $0 \to (+ e) + (- e) + 0$