David Sang and Graham Jones Solutions for Chapter: Kirchhoff's Laws, Exercise 6: Questions

Use the idea of the energy gained and lost by a IC charge to explain why two$6 \mathrm{V}$ batteries connected together in series can give an e.m.f. of $12 \mathrm{V}$ or $0 \mathrm{V}$, but connected in parallel they give an e.m.f. of $6 \mathrm{V}$$.$

Apply Kirchhoff's laws to the circuit shown in Figure to determine the current that will be shown by the ammeters ${\mathrm{A}}_1, {\mathrm{A}}_2$ and ${\mathrm{A}}_3.$